Science.gov

Sample records for composite pavements

  1. Energy harvesting in pavement from passing vehicles with piezoelectric composite plate for ice melting

    NASA Astrophysics Data System (ADS)

    Faisal, Farjana; Wu, Nan; Kapoor, Kartik

    2016-04-01

    An energy harvester in the road pavement made from a piezoelectric composite plate is designed and studied to collect energy from the passing vehicles for the ice melting aim. Piezoelectric material has the ability to produce electric charge on its surface when strain takes place due to any external loading. Based on this property, a rectangular composite plate harvester is developed consisting of piezoelectric material as the energy generation coating layer and A514 steel as the substrate layer to realize the energy harvesting process from the variable pressure generated in the road pavement by passing vehicles. Based on Westergaards stress model, a numerical model is developed to calculate the three dimensional stress distribution in the pavement. Numerical simulations are conducted to study the optimization of various parameters of the harvester, such as depth of the harvester in the pavement, length and width as well as thicknesses of piezoelectric layer and the substrate. By taking in to consideration the maximum stress that can be sustained by both of the piezoelectric material and also the substrate material, an optimum design of the piezoelectric couple composite plate energy harvester is suggested. It is seen that the maximum output power, which can be generated by a single patch of 0.2m*0.2m*0.0026m dimension with a vehicle passing at 22.2 m/s, can reach up to 23.36 W. With the well-designed pavement energy harvesters, it is feasible to collect enough energy to rise the temperature of the ice with the thickness of 1cm covering a 5m width road by 20 degree Celsius within 2.5 hours. This technique can be applied to melt the ice on the roads and bridges especially in cold countries.

  2. A fiber-reinforced composite structure for the repair of thermally cracked bituminous pavements

    NASA Astrophysics Data System (ADS)

    Frantzen, Jeffrey Alan

    1998-10-01

    The apparatus under development in this project is a structural component or beam fabricated from a fiber reinforced plastic composite (FRPC). The FRPC beam is a structural repair component intended to bridge a deteriorated thermal crack in full depth bituminous pavements or partial depth bituminous pavements over portland cement concrete. The bridging action provided by the FRPC beam is intended to minimize roughness through the repaired area for up to five years, eliminate reappearance of the deteriorated crack, and provide a controlled expansion crack that can be treated with standard sealing techniques. This apparatus is designed for maintenance use as a field expedient, semi-permanent repair using tools that are commonly available at the Area Maintenance level. Three FRPC beams were constructed for field trial in a thermally cracked, full depth bituminous pavement on US-36 east of Hiawatha, Kansas. Each of the beams were instrumented with bonded metal foil strain gages and field installation by KDOT Maintenance forces was done in August and September of 1997. The FRPC beams have been evaluated since installation and this evaluation will continue for up to five years. Evaluation of the beams has been accomplished through static load tests using the strain gage instrumentation and Falling Weight Deflectometer measurements. The FRPC beams have performed satisfactorily as of the date of writing.

  3. Pavement management

    SciTech Connect

    Ross, F.R.; Connor, B.; Lytton, R.L.; Darter, M.I.; Shahin, M.Y.

    1982-01-01

    The 11 papers in this report deal with the following areas: effect of pavement roughness on vehicle fuel consumption; rational seasonal load restrictions and overload permits; state-level pavement monitoring program; data requirements for long-term monitoring of pavements as a basis for development of multiple regression relations; simplified pavement management at the network level; combined priority programming of maintenance and rehabilitation for pavement networks; Arizona pavement management system: Phase 2-verification of performance prediction models and development of data base; overview of paver pavement management system; economic analysis of field implementation of paver pavement management system; development of a statewide pavement maintenance management system; and, prediction of pavement maintenance expenditure by using a statistical cost function.

  4. Size and composition of airborne particles from pavement wear, tires, and traction sanding.

    PubMed

    Kupiainen, Kaarle J; Tervahattu, Heikki; Räisänen, Mika; Mäkelä, Timo; Aurela, Minna; Hillamo, Risto

    2005-02-01

    Mineral matter is an important component of airborne particles in urban areas. In northern cities of the world, mineral matter dominates PM10 during spring because of enhanced road abrasion caused by the use of antiskid methods, including studded tires and traction sanding. In this study, factors that affect formation of abrasion components of springtime road dust were assessed. Effects of traction sanding and tires on concentrations, mass size distribution, and composition of the particles were studied in a test facility. Lowest particle concentrations were observed in tests without traction sanding. The concentrations increased when traction sand was introduced and continued to increase as a function of the amount of aggregate dispersed. Emissions were additionally affected by type of tire, properties of traction sand aggregate, and driving speed. Aggregates with high fragmentation resistance and coarse grain size distribution had the lowest emissions. Over 90% of PM10 was mineral particles. Mineralogy of the dust and source apportionment showed that they originated from both traction sand and pavement aggregates. The remaining portion was mostly carbonaceous and originated from tires and road bitumen. Mass size distributions were dominated by coarse particles. Contribution of fine and submicron size ranges were approximately 15 and 10% in PM10, respectively. PMID:15757329

  5. Influence of mixture composition on the noise and frictional characteristics of flexible pavements

    NASA Astrophysics Data System (ADS)

    Kowalski, Karol J.

    Both traffic noise and wet pavement-tire friction are mainly affected by the tire/pavement interaction. Existing laboratory test methods allow for evaluation of polishing resistance of the aggregates only. Currently, there is no generally accepted standardized laboratory test method to address noise related issues and the overall frictional properties of pavements (including macrotexture). In this research, which included both laboratory and field components, friction and noise properties of the flexible (asphalt) pavements were investigated. As a part of this study, a laboratory device to polish asphalt specimens was developed and the procedure to evaluate mixture frictional properties was proposed. Following this procedure, forty-six different Superpave mixtures (each utilizing a different aggregate blends), one stone matrix asphalt (SMA) mixture and one porous friction course (PFC) mixture were tested. Six of the above mixes (four Superpave mixtures, SMA mixture and PFC mixture) were selected for laboratory noise testing. This testing was performed using a one-of-a-kind tester called the Tire/Pavement Test Apparatus (TPTA). In addition, the field sections constructed using Superpave, SMA and PFC mixtures were also periodically tested for friction and noise. Field measurements included testing of total of 23 different asphalt and two concrete pavements. The field friction testing was performed using both portable CTM and DFT devices and the (ASTM E 274) locked wheel friction trailer. The laboratory friction testing was performed using CTM and DFT devices only. The results of both field and laboratory friction measurements were used to develop an International Friction Index (IFI)-based frictional requirement for laboratory friction measurements. The results collected in the course of the study indicate that the IFI-based flag values could be successfully used in place of SN-based flag values to characterize frictional characteristics of pavements.

  6. Advanced self-healing asphalt composites in the pavement performance field: mechanisms at the nano level and new repairing methodologies.

    PubMed

    Agzenai, Yahya; Pozuelo, Javier; Sanz, Javier; Perez, Ignacio; Baselga, Juan

    2015-01-01

    In an effort to give a global view of this field of research, in this mini-review we highlight the most recent publications and patents focusing on modified asphalt pavements that contain certain reinforcing nanoparticles which impart desirable thermal, electrical and mechanical properties. In response to the increasing cost of asphalt binder and road maintenance, there is a need to look for alternative technologies and new asphalt composites, able to self-repair, for preserving and renewing the existing pavements. First, we will focus on the self-healing property of asphalt, the evidences that support that healing takes place immediately after the contact between the faces of a crack, and how the amount of healing can be measured in both the laboratory and the field. Next we review the hypothetical mechanisms of healing to understand the material behaviour and establish models to quantify the damage-healing process. Thereafter, we outline different technologies, nanotechnologies and methodologies used for self-healing paying particular attention to embedded micro-capsules, new nano-materials like carbon nanotubes and nano-fibres, ionomers, and microwave and induction heating processes. PMID:25479339

  7. Pavement evaluation and rehabilitation

    SciTech Connect

    Ali, N.A.; Khosla, N.P.; Johnson, E.G.; Hicks, R.G.; Uzan, J.

    1987-01-01

    The 20 papers in this report deal with the following areas: determination of layer moduli using a falling weight deflectometer; evaluation of effect of uncrushed base layers on pavement performance; the effect of contact area shape and pressure distribution on multilayer systems response; sensitivity analysis of selected backcalculation procedures; performance of a full-scale pavement design experiment in Jamaica; subsealing and load-transfer restoration; development of a demonstration prototype expert system for concrete pavement evaluation; numerical assessment of pavement test sections; development of a distress index and rehabilitation criteria for continuously reinforced concrete pavements using discriminant analysis; a mechanistic model for thermally induced reflection cracking of portland cement concrete pavement with reinforced asphalt concrete overlay; New Mexico study of interlayers used in reflective crack control; status of the South Dakota profilometer; incorporating the effects of tread pattern in a dynamic tire excitation mechanism; external methods for evaluating shock absorbers for road-roughness measurements; factor analysis of pavement distresses for surface condition predictions; development of a utility evaluation for nondestructive-testing equipment used on asphalt-concrete pavements; estimating the life of asphalt overlays using long-term pavement performance data; present serviceability-roughness correlations using rating panel data; video image distress analysis technique for Idaho transportation department pavement-management system; acceptability of shock absorbers for road roughness-measuring trailers.

  8. Pavement condition data analysis

    SciTech Connect

    Zaniewski, J.P.; Hudson, S.W.; Hudson, W.R.

    1987-07-01

    This paper describes a computer methodology for analyzing pavement condition data to define inputs for pavement management systems. This system of programs was developed during a Federal Highway Administration research project. In the project, eight state highway departments were studied to determine the types of pavement condition data collected, procedures used for collecting data, the inputs to the states' pavement management systems, and computer programs used by the states to analyze raw pavement condition data. Several of the programs were assembled into the Method for Analyzing Pavement Condition, MAPCON, during a project performed at Pennsylvania State University. These and other existing or new programs (a total of 18) were identified, tested, modified, and incorporated onto a MS/DOS microcomputer system. MAPCON guides the user through selection of analysis method, raw data entry, and data analysis.

  9. Asphalt in Pavement Maintenance.

    ERIC Educational Resources Information Center

    Asphalt Inst., College Park, MD.

    Maintenance methods that can be used equally well in all regions of the country have been developed for the use of asphalt in pavement maintenance. Specific information covering methods, equipment and terminology that applies to the use of asphalt in the maintenance of all types of pavement structures, including shoulders, is provided. In many…

  10. Study on Flexible Pavement Failures in Soft Soil Tropical Regions

    NASA Astrophysics Data System (ADS)

    Jayakumar, M.; Chee Soon, Lee

    2015-04-01

    Road network system experienced rapid upgrowth since ages ago and it started developing in Malaysia during the colonization of British due to its significant impacts in transportation field. Flexible pavement, the major road network in Malaysia, has been deteriorating by various types of distresses which cause descending serviceability of the pavement structure. This paper discusses the pavement condition assessment carried out in Sarawak and Sabah, Malaysia to have design solutions for flexible pavement failures. Field tests were conducted to examine the subgrade strength of existing roads in Sarawak at various failure locations, to assess the impact of subgrade strength on pavement failures. Research outcomes from field condition assessment and subgrade testing showed that the critical causes of pavement failures are inadequate design and maintenance of drainage system and shoulder cross fall, along with inadequate pavement thickness provided by may be assuming the conservative value of soil strength at optimum moisture content, whereas the exiting and expected subgrade strengths at equilibrium moisture content are far below. Our further research shows that stabilized existing recycled asphalt and base materials to use as a sub-base along with bitumen stabilized open graded base in the pavement composition may be a viable solution for pavement failures.

  11. Pavement management practices. Final report

    SciTech Connect

    Peterson, D.E.

    1987-11-01

    This synthesis will be of interest to pavement designers, maintenance engineers, and others responsible for the management of highway pavements. Information is presented on pavement management systems - the established, documented procedures used to treat all activities involved in providing and sustaining pavements in an acceptable condition. As highway agencies focus more attention on maintenance and rehabilitation of highway networks, the use of some form of a pavement management system becomes increasingly important. This report of the Transportation Research Board describes the features, applicability, and used of a pavement management system and recommends five general steps for implementing a new pavement management system or improving an existing system.

  12. Pervious Pavement System Evaluation

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, grade...

  13. Dynamic pavement deflection

    NASA Astrophysics Data System (ADS)

    Rand, D. W.; Jacobs, K. M.

    1981-06-01

    Dynamic pavement deflection measurements for bituminous concrete pavements of two and three-quarter, five and seven-eights, and seven and one-half inches in thickness under moving axle loads of 15,000, 18,000, and 22,000 pounds were obtained at speeds of 10, 25 and 45 miles per hour. The results were analyzed and compared to Benkelman beam measurements. The data indicate that slow moving loads have greater adverse effect (larger deflections) on the pavement than the high speed loads. The results also show that the bituminous pavement undergoes numerous vertical fluctuations and bending as the front and rear axles approached the point of measurement. The magnitude of the vertical displacement was measured via the means of an accelerometer and double integrator. When values of the dynamic deflections were in the magnitude of 0.07 through 0.10 inches, there was evidence of pavement failure. When the deflection values were above 0.10 inches pavement failures were distinct.

  14. Evaluation of pavement texture

    NASA Astrophysics Data System (ADS)

    Henry, J. J.; Wambold, J. C.; Huihua, X.

    1984-10-01

    A system for pavement macrotexture measurement was evaluated. The system utilizes the principle of depolarization of reflected polarized light. The output of the system, the depolarized light number (DPN), is compared with other measures of pavement texture: sand-patch mean texture depth (MTD), British pendulum number (BPN), and outflow meter time (OFT) for 22 asphalt concrete sites and 5 portland cement concrete sites. The prediction of texture data from simultaneous measurements of ribbed and blank-tire skid resistance data was investigated. Using the two-tire data, it is possible to predict sand-patch mean texture depth (MTD) and Bristish pendulum number (BPN). Comparison of the two-tire data at accident sites demonstrates the potential to screen for wet weather accident sites by means of pavement surveys with the two tires.

  15. High altitude premium pavements

    NASA Astrophysics Data System (ADS)

    Abel, F.; Proctor, J.

    1980-02-01

    The effect on performance that various additives and, or compaction had on the performance of pavements was evaluated. The following additives were evaluated: Anti-stripping additives, ground scrap rubber and carbon black. Samples were also evaluated at approximately 0, 3, 10 and 15% voids to determine the effect compaction had on the performance of the pavement. The resilient modulus, effect of water on cohesion of compacted bituminous mixtures and an accelerated moisture damage test was performed on each design mix. Most of the additives did not show significant, if any, improvement in the laboratory test results. The best improvement in laboratory test results came from the anti-stripping asphalt additives, which is one of the least costly and simplest to include in the pavement mixture.

  16. Pervious Pavement System Evaluation

    EPA Science Inventory

    Pervious pavement is a low impact development stormwater control. The Urban Watershed Management Branch of the U.S. Environmental Protection Agency in Edison, NJ, is evaluating concrete pavers as a popular implementation. The pollutant removal of a bench-scale permeable interlo...

  17. Geotextiles in Flexible Pavement Construction

    ERIC Educational Resources Information Center

    Alungbe, Gabriel D.

    2004-01-01

    People everywhere in the developed world regularly drive on paved roads. Learning about the construction techniques and materials used in paving benefits technology and construction students. This article discusses the use of geosynthetic textiles in pavement construction. It presents background on pavements and describes geotextiles and drainage…

  18. Pavement recycling. Executive summary and report

    SciTech Connect

    1995-10-01

    The Federal Highway Administration (FHWA) initiated Demonstration Project 39 (DP 39) Recycling Asphalt Pavements in June 1976. The project showed that asphalt pavement recycling was a technically viable rehabitation technique, and it was estimated that the use of reclaimed asphalt pavement (RAP) would amount to approximately 15 percent of the total hot-mix asphalt (HMA) production by the mid-1980s. It was expected that most of the asphalt pavement removed would be reused in new pavement construction or overlays.

  19. Pervious Pavement System Evaluation- Abstract

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  20. Pavement management using hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Ayalew, Balehager; Gomez, Richard B.; Roper, William E.; Carrasco, Oscar

    2003-08-01

    Public Works facilities require up-to-date information on the health status of the road network they maintain. However, roadway maintenance and rehabilitation involves the greatest portion of a municipality's annual operating budget. Government officials use various technologies such as a pavement management system to assist in making better decisions about their roadways systems, pavement condition, history, and projects. Traditionally, manual surveying has served as the method of obtaining this information. To better assist in decision-making, a regionally specific spectral library for urban areas is being developed and used in conjunction with hyperspecrtal imaging, to map urban materials and pavement conditions. A Geographical Information and Positioning System (GIS/GPS) will also be implemented to overlay relative locations. This paper will examine the benefits of using hyperspectral imaging over traditional methods of roadway maintenance and rehabilitation for pavement management applications. In doing so, we will identify spatial and spectral requirements for successful large-scale road feature extraction.

  1. Quantifying Evaporation in a Permeable Pavement System

    EPA Science Inventory

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  2. Pervious Pavement System Evaluation-Poster

    EPA Science Inventory

    Pervious pavement is a low impact development stormwater control. The Environmental Protection Agency's Urban Watershed Management Branch is evaluating interlocking concrete pavingstone pervious pavement systems. The pavingstones themselves are impermeable, but the spaces between...

  3. Solar-reflective coating as a cooling overlay for asphalt pavement

    NASA Astrophysics Data System (ADS)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2011-11-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  4. Solar-reflective coating as a cooling overlay for asphalt pavement

    NASA Astrophysics Data System (ADS)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2012-04-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  5. Impact of pavement conditions on crash severity.

    PubMed

    Li, Yingfeng; Liu, Chunxiao; Ding, Liang

    2013-10-01

    Pavement condition has been known as a key factor related to ride quality, but it is less clear how exactly pavement conditions are related to traffic crashes. The researchers used Geographic Information System (GIS) to link Texas Department of Transportation (TxDOT) Crash Record Information System (CRIS) data and Pavement Management Information System (PMIS) data, which provided an opportunity to examine the impact of pavement conditions on traffic crashes in depth. The study analyzed the correlation between several key pavement condition ratings or scores and crash severity based on a large number of crashes in Texas between 2008 and 2009. The results in general suggested that poor pavement condition scores and ratings were associated with proportionally more severe crashes, but very poor pavement conditions were actually associated with less severe crashes. Very good pavement conditions might induce speeding behaviors and therefore could have caused more severe crashes, especially on non-freeway arterials and during favorable driving conditions. In addition, the results showed that the effects of pavement conditions on crash severity were more evident for passenger vehicles than for commercial vehicles. These results provide insights on how pavement conditions may have contributed to crashes, which may be valuable for safety improvement during pavement design and maintenance. Readers should notice that, although the study found statistically significant effects of pavement variables on crash severity, the effects were rather minor in reality as suggested by frequency analyses. PMID:23892046

  6. Teaching Methodology of Flexible Pavement Materials and Pavement Systems

    ERIC Educational Resources Information Center

    Mehta, Yusuf; Najafi, Fazil

    2004-01-01

    Flexible pavement materials exhibit complex mechanical behavior, in the sense, that they not only show stress and temperature dependency but also are sensitive to moisture conditions. This complex behavior presents a great challenge to the faculty in bringing across the level of complexity and providing the concepts needed to understand them. The…

  7. Pavement thickness evaluation using ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Harris, Dwayne Arthur

    Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement management and design. Much of the time this information is missing, out of date, or unknown for highway sections. Current technologies for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement thickness information; however, it is also time consuming, labor intensive, intrusive to traffic, destructive, and limited in coverage. FWD provides nondestructive estimates of both a surface thickness and total pavement structure thickness, including pavement, base and sub-base. On the other hand, FWD is intrusive to traffic and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement surface course thickness estimates with excellent data coverage at highway speed. Yet, disadvantages include the pavement thickness estimation being affected by the electrical properties of the pavement, limitations of the system utilized, and heavy post processing of the data. Nevertheless, GPR has been successfully utilized by a number of departments of transportation (DOTs) for pavement thickness evaluation. This research presents the GPR thickness evaluation methods, develops GPRPAVZ the software used to implement the methodologies, and addresses the quality of GPR pavement thickness evaluation.

  8. Mechanistic interpretation of nondestructive pavement testing deflections

    NASA Astrophysics Data System (ADS)

    Hoffman, M. S.

    1980-06-01

    A method is proposed for the backcalculation of material properties in flexible pavements based on the interpretation of surface deflection measurements. ILLI-PAVE, a stress dependent finite element pavement model, was used to generate data for developing algorithms and nomographs for deflection basin interpretation. Over 11,000 deflection measurements for 24 different flexible pavement sections were collected and analyzed. Deflections were measured using the Benkelman Beam, the IDOT Road Rater, the Falling Weight Deflectometer, and an accelerometer to measure deflections under moving trucks. Loading mode effects on pavement response were investigated using dynamic and viscous pavement models. The factors controlling the pavement response to different loading modes were explained and identified. Correlations between different devices were developed. The proposed evaluation procedure is illustrated for three different flexible pavements using deflection data collected on several testing dates.

  9. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  10. Evolution of desert pavements and the vesicular layer in soils of the Transantarctic Mountains

    NASA Astrophysics Data System (ADS)

    Bockheim, James G.

    2010-06-01

    Compared to mid-latitude deserts, the properties, formation and evolution of desert pavements and the underlying vesicular layer in Antarctica are poorly understood. This study examines the desert pavements and the vesicular layer from seven soil chronosequences in the Transantarctic Mountains that have developed on two contrasting parent materials: sandstone-dolerite and granite-gneiss. The pavement density commonly ranges from 63 to 92% with a median value of 80% and does not vary significantly with time of exposure or parent material composition. The dominant size range of clasts decreases with time of exposure, ranging from 16-64 mm on Holocene and late Quaternary surfaces to 8-16 mm on surfaces of middle Quaternary and older age. The proportion of clasts with ventifaction increases progressively through time from 20% on drifts of Holocene and late Quaternary age to 35% on Miocene-aged drifts. Desert varnish forms rapidly, especially on dolerite clasts, with nearly 100% cover on surfaces of early Quaternary and older age. Macropitting occurs only on clasts that have been exposed since the Miocene. A pavement development index, based on predominant clast-size class, pavement density, and the proportion of clasts with ventifaction, varnish, and pits, readily differentiated pavements according to relative age. From these findings we judge that desert pavements initially form from a surficial concentration of boulders during till deposition followed by a short period of deflation and a longer period of progressive chemical and physical weathering of surface clasts. The vesicular layer that underlies the desert pavement averages 4 cm in thickness and is enriched in silt, which is contributed primarily by weathering rather than eolian deposition. A comparison is made between desert pavement properties in mid-latitude deserts and Antarctic deserts.

  11. Continuous monitoring of mining induced strain in a road pavement using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Nosenzo, Giorgio; Whelan, B. E.; Brunton, M.; Kay, Daryl; Buys, Henk

    2013-06-01

    This paper describes the application of fiber Bragg grating (FBG) based sensors for monitoring road pavement strains caused by mining induced ground subsidence as a result of underground longwall coal mining beneath a major highway in New South Wales, Australia. After a lengthy planning period, the risks to the highway pavement were successfully managed by the highway authority and the mining company through a technical committee. The technical committee comprised representatives of the mining company, the highway authority and specialists in the fields of pavement engineering, geotechnical engineering and subsidence. An important component of the management strategy is the installation of a total of 840 strain and temperature sensors in the highway pavement using FBG arrays encapsulated in glass-fiber composite cables. The sensors and associated demodulation equipment provide continuous strain measurements along the pavement, enabling on-going monitoring of the effects of mining subsidence on the pavement and timely implementation of planned mitigation and response measures to ensure the safety and serviceability of the highway throughout the mining period.

  12. Continuous monitoring of mining induced strain in a road pavement using fibre Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Whelan, B. E.; Brunton, M.; Nosenzo, Giorgio; Kay, Daryl; Buys, Henk

    2012-02-01

    This paper describes the application of Fibre Bragg Grating (FBG) based sensors for monitoring road pavement strains caused by mining induced ground subsidence as a result of underground longwall coal mining beneath a major highway in New South Wales, Australia. After a lengthy planning period, the risks to the highway pavement were successfully managed by the highway authority and the mining company through a technical committee. The technical committee comprised representatives of the mining company, the highway authority and specialists in the fields of pavement engineering, geotechnical engineering and subsidence. An important component of the management strategy is the installation of a total of 840 strain and temperature sensors in the highway pavement using FBG arrays encapsulated in glass-fibre composite cables. The sensors and associated demodulation equipment provide continuous strain measurements along the pavement, enabling on-going monitoring of the effects of mining subsidence on the pavement and timely implementation of planned mitigation and response measures to ensure the safety and serviceability of the highway throughout the mining period.

  13. Asphalt pavement aging and temperature dependent properties using functionally graded viscoelastic model

    NASA Astrophysics Data System (ADS)

    Dave, Eshan V.

    Asphalt concrete pavements are inherently graded viscoelastic structures. Oxidative aging of asphalt binder and temperature cycling due to climatic conditions being the major cause of non-homogeneity. Current pavement analysis and simulation procedures dwell on the use of layered approach to account for these non-homogeneities. The conventional finite-element modeling (FEM) technique discretizes the problem domain into smaller elements, each with a unique constitutive property. However the assignment of unique material property description to an element in the FEM approach makes it an unattractive choice for simulation of problems with material non-homogeneities. Specialized elements such as "graded elements" allow for non-homogenous material property definitions within an element. This dissertation describes the development of graded viscoelastic finite element analysis method and its application for analysis of asphalt concrete pavements. Results show that the present research improves efficiency and accuracy of simulations for asphalt pavement systems. Some of the practical implications of this work include the new technique's capability for accurate analysis and design of asphalt pavements and overlay systems and for the determination of pavement performance with varying climatic conditions and amount of in-service age. Other application areas include simulation of functionally graded fiber-reinforced concrete, geotechnical materials, metal and metal composites at high temperatures, polymers, and several other naturally existing and engineered materials.

  14. Environmental history recorded in aeolian deposits under stone pavements, Mojave Desert, USA

    NASA Astrophysics Data System (ADS)

    Dietze, Michael; Dietze, Elisabeth; Lomax, Johanna; Fuchs, Markus; Kleber, Arno; Wells, Stephen G.

    2016-01-01

    Reconstructing the evolution of arid landscapes is challenged by limited availability of appropriate environmental archives. A widespread surface feature - stone pavement - traps aeolian fines and forms a special accretionary archive. Seven stone pavement-covered sections on basalt flows in the eastern Mojave Desert are condensed into a composite section, comprising five sedimentological units supported by an OSL-based chronology. Three of the units are of accretionary nature and each is covered by a stone pavement. They were deposited > 50.9-36.6 ka, < 36.6-14.2 ka and < 14.2 ka, and they are intimately coupled with the history of nearby Lake Mojave, which advances the current understanding of regional aeolian activity. End-member modeling analysis of grain-size distributions yielded seven sediment transport regimes. The accretionary system operates in two modes: A) episodic formation of a stone pavement by lateral processes once a vesicular horizon has formed on a barren surface; and B) accretion of dust and eventual burial of the clast layer. These findings improve current concepts about stone pavement evolution and their environmental proxy function in arid landscapes. Stone pavement-covered accretionary deposits are a new key archive that allows quantifying the relative importance of dust accretion, slope processes, soil formation and vegetation cover.

  15. Pervious Pavement System Evaluation-Paper

    EPA Science Inventory

    The use of a pervious pavement can be effective as a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete paver systems as a type of porous pavement. Although the pavers are impermeable, the spaces between the pave...

  16. Predicting pavement distress in oil field areas

    SciTech Connect

    Mason, J.M.; Scullion, T.; Stampley, B.E.

    1984-05-01

    A study on oil field traffic characteristics was performed and a procedure was developed for assessing current and future effects of oil field truck traffic on surface-treated (stage construction type) pavements. A computer program calculates several types of pavement distress and serviceability parameters to evaluate pavement performance under various axle load repetitions. Stepwise regression analysis of 132 surface-treated pavement sections led to the development of individual distress equations for rutting, raveling, flushing, alligator cracking, patching, longitudinal and transverse cracking, and failures (potholes). The versatility of the program provides a means of anticipating early pavement failures due to increased axle load repetitions. The program also provides the basic framework for computing the effects of other ''special-use'' truck traffic demands.

  17. Predicting pavement distress in oil field areas

    SciTech Connect

    Mason, J.M.; Scullion, T.; Stampley, B.E.

    1983-05-01

    A study on oil field traffic characteristics was performed and a procedure was developed for assessing current and future effects of oil field truck traffic on surface-treated (stage construction type) pavements. A computer program calculates several types of pavement distress and serviceability parameters to evaluate pavement performance under various axle load repetitions. Stepwise regression analysis of 132 surface-treated pavement sections led to the development of individual distress equations for rutting, raveling, flushing, alligator cracking, patching, longitudinal and transverse cracking, and failures (potholes). The versatility of the program provides a means of anticipating early pavement failures due to increased axle load repetitions. The program also provides the basic framework for computing the effects of other ''special-use'' truck traffic demands.

  18. Pavement distress detection and severity analysis

    NASA Astrophysics Data System (ADS)

    Salari, E.; Bao, G.

    2011-03-01

    Automatic recognition of road distresses has been an important research area since it reduces economic loses before cracks and potholes become too severe. Existing systems for automated pavement defect detection commonly require special devices such as lights, lasers, etc, which dramatically increase the cost and limit the system to certain applications. Therefore, in this paper, a low cost automatic pavement distress evaluation approach is proposed. This method can provide real-time pavement distress detection as well as evaluation results based on the color images captured from a camera installed on a survey vehicle. The entire process consists of two main parts: pavement surface extraction followed by pavement distress detection and classification. In the first part, a novel color segmentation method based on a feed forward neural network is applied to separate the road surface from the background. In the second part, a thresholding technique based on probabilistic relaxation is utilized to separate distresses from the road surface. Then, by inputting the geometrical parameters obtained from the detected distresses into a neural network based pavement distress classifier, the defects can be classified into different types. Simulation results are given to show that the proposed method is both effective and reliable on a variety of pavement images.

  19. Pavement crack characteristic detection based on sparse representation

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoming; Huang, Jianping; Liu, Wanyu; Xu, Mantao

    2012-12-01

    Pavement crack detection plays an important role in pavement maintaining and management. The three-dimensional (3D) pavement crack detection technique based on laser is a recent trend due to its ability of discriminating dark areas, which are not caused by pavement distress such as tire marks, oil spills and shadows. In the field of 3D pavement crack detection, the most important thing is the accurate extraction of cracks in individual pavement profile without destroying pavement profile. So after analyzing the pavement profile signal characteristics and the changeability of pavement crack characteristics, a new method based on the sparse representation is developed to decompose pavement profile signal into a summation of the mainly pavement profile and cracks. Based on the characteristics of the pavement profile signal and crack, the mixed dictionary is constructed with an over-complete exponential function and an over-complete trapezoidal membership function, and the signal is separated by learning in this mixed dictionary with a matching pursuit algorithm. Some experiments were conducted and promising results were obtained, showing that we can detect the pavement crack efficiently and achieve a good separation of crack from pavement profile without destroying pavement profile.

  20. Assessment of highway pavements using GPR

    NASA Astrophysics Data System (ADS)

    Plati, Christina; Loizos, Andreas

    2015-04-01

    Highway infrastructure is a prerequisite for a functioning economy and social life. Highways, often prone to congestion and disruption, are one of the aspects of a modern transport network that require maximum efficiency if an integrated transport network, and sustainable mobility, is to be achieved. Assessing the condition of highway structures, to plan subsequent maintenance, is essential to allow the long-term functioning of a road network. Optimizing the methods used for such assessment will lead to better information being obtained about the road and underlying ground conditions. The condition of highway structures will be affected by a number of factors, including the properties of the highway pavement, the supporting sub-base and the subgrade (natural ground), and the ability to obtain good information about the entire road structure, from pavement to subgrade, allows appropriate maintenance programs to be planned. The maintenance of highway pavements causes considerable cost and in many cases obstruction to traffic flow. In this situation, methods that provide information on the present condition of pavement structure non-destructively and economically are of great interest. It has been shown that Ground-Penetrating-Radar (GPR), which is a Non Destructive Technique (NDT), can deliver information that is useful for the planning of pavement maintenance activities. More specifically GPR is used by pavement engineers in order to determine physical properties and characteristics of the pavement structure, information that is valuable for the assessment of pavement condition. This work gives an overview on the practical application of GPR using examples from highway asphalt pavements monitoring. The presented individual applications of GPR pavement diagnostics concern structure homogeneity, thickness of pavement layers, dielectric properties of asphalt materials etc. It is worthwhile mentioning that a number of applications are standard procedures, either

  1. Permeable Pavement Research - Edison, New Jersey

    EPA Science Inventory

    This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

  2. Pervious Pavement System Evaluation- Abstract 1

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  3. Reducing traffic noise with quieter pavements

    NASA Astrophysics Data System (ADS)

    Donavan, Paul

    2005-09-01

    In recent years, interest has increased in the use of pavement type to reduce traffic noise. This has been driven by public concern over noise from freeways and state transportation agencies' interest in using pavement instead of sound walls to mitigate traffic noise. Beginnings of the recent interest go back to 1998 with the formation of the Institute for Safe, Quiet & Durable Highways at Purdue University and the initiation long-term research by the California Department of Transportation (Caltrans) on the effectiveness of quieter pavements. In 2002, the State of Arizona announced plans to overlay 115 miles of concrete freeway in the greater Phoenix area with a quieter asphalt rubber surface. This turned into the first Quiet Pavement Pilot Program in partnership between Federal Highway Administration (FHWA) and the Arizona Department of Transportation. Since that time, the FHWA in cooperation with the American Association of State Highway Transportation Agencies conducted a fact finding ``Scan'' tour in Europe to evaluate their quiet pavement technology and policy. This was followed by the first comparative tire/pavement noise testing in the US and Europe using the same procedures and test tires. The results, issues, and future directions surrounding these activities will be discussed.

  4. Fusing complementary images for pavement cracking measurements

    NASA Astrophysics Data System (ADS)

    Yao, Ming; Zhao, Zuyun; Yao, Xun; Xu, Bugao

    2015-02-01

    Cracking is a major pavement distress that jeopardizes road serviceability and traffic safety. Automated pavement distress survey (APDS) systems have been developed using digital imaging technology to replace human surveys for more timely and accurate inspections. Most APDS systems require special lighting devices to illuminate pavements and prevent shadows of roadside objects that distort cracks in the image. Most artificial lighting devices are laser based, and are either hazardous to unprotected people or require dedicated power supplies on the vehicle. This study was aimed to develop a new imaging system that can scan pavement surface at highway speed and determine the level of severity of pavement cracking without using any artificial lighting. The new system consists of dual line-scan cameras that are installed side by side to scan the same pavement area as the vehicle moves. Cameras are controlled with different exposure settings so that both sunlit and shadowed areas can be visible in two separate images. The paired images contain complementary details useful for reconstructing an image in which the shadows are eliminated. This paper intends to present (1) the design of the dual line-scan camera system, (2) a new calibration method for line-scan cameras to rectify and register paired images, (3) a customized image-fusion algorithm that merges the multi-exposure images into one shadow-free image for crack detection, and (4) the results of the field tests on a selected road over a long period.

  5. Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions

    PubMed Central

    Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results. PMID:24027444

  6. POROUS PAVEMENT. PHASE I. DESIGN AND OPERATIONAL CRITERIA

    EPA Science Inventory

    Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

  7. Spills on Flat Inclined Pavements

    SciTech Connect

    Simmons, Carver S.; Keller, Jason M.; Hylden, Jeff L.

    2004-03-01

    This report describes the general spill phenomenology for liquid spills occurring on relatively impermeable surfaces such as concrete or asphalt pavement and the development and application of a model to describe the time evolution of such spills. The discussion assumes evaporation and degradation are negligible and a homogeneous surface. In such an instance, the inherent interfacial properties determine the spatial extent of liquid spreading with the initial flow being controlled by the release rate of the spill and by the liquids resistance to flow as characterized by its viscosity. A variety of spill scenarios were simulated and successful implementation of the model was achieved. A linear relationship between spill area and spill volume was confirmed. The simulations showed spill rate had little effect on the final spill area. Slope had an insignificant effect on the final spill area, but did modify spill shape considerably. However, a fluid sink on the edge of the simulation domain, representing a storm drain, resulted in a substantial decrease in spill area. A bona fide effort to determine the accuracy of the model and its calculations remain, but comparison against observations from a simple experiment showed the model to correctly determine the spill area and general shape under the conditions considered. Further model verification in the form of comparison against small scale spill experiments are needed to confirm the models validity.

  8. Overview of the Arizona Quiet Pavement Program

    NASA Astrophysics Data System (ADS)

    Donavan, Paul; Scofield, Larry

    2005-09-01

    The Arizona Quiet Pavement Pilot Program (QP3) was initially implemented to reduce highway related traffic noise by overlaying most of the Phoenix metropolitan area Portland cement concrete pavement with a one inch thick asphalt rubber friction coarse. With FHWA support, this program represents the first time that pavement surface type has been allowed as a noise mitigation strategy on federally funded projects. As a condition of using pavement type as a noise mitigation strategy, ADOT developed a ten-year, $3.8 million research program to evaluate the noise reduction performance over time. Historically, pavement surface type was not considered a permanent solution. As a result, the research program was designed to specifically address this issue. Noise performance is being evaluated through three means: (1) conventional roadside testing within the roadway corridor (e.g., far field measurements within the right-of-way) (2) the use of near field measurements, both close proximity (CPX) and sound intensity (SI); and (3) far field measurements obtained beyond the noise barriers within the surrounding neighborhoods. This paper provides an overview of the program development, presents the research conducted to support the decision to overlay the urban freeway, and the status of current research.

  9. ACAA pavement manual. Recommended practice: Coal fly ash in pozzolanic stabilized mixtures for flexible pavement systems

    SciTech Connect

    Not Available

    1991-01-01

    The purpose of this manual is to guide pavement design engineers, materials engineers, and construction managers in the design and construction of flexible pavement systems in which low- to high-strength Pozzolanic Stabilized Mixtures' ( PSMs') serve as base layers. A PSM incorporates coal fly ash in combination with activators, aggregates and water. Each of three design methods is useful for determining the thickness of a PSM base layer for a flexible pavement system: Method A - American Association of State Highway and Transportation Officials (AASHTO) flexible pavement design procedures, using structural layer coefficients; Method B - Mechanistic pavement design procedures, using resilient modulus values for the pavement layers; and Method C - A combination of Method A and Method B, using mechanistic design concepts for determining pavement layer coefficients. PSMs offer several advantages: PSMs are strong, durable mixtures using locally available materials; PSMs are economically competitive with properly engineered full-depth asphalt or crushed stone base courses; PSMs are suited to stabilizing recycled base mixtures; and PSMs are placed and compacted with conventional construction equipment. To provide the needed guidance for capturing the long-term service and cost-saving features of a PSM design, this manual details the following: a procedure for proportioning PSMs; thickness design procedures which include base layer and asphalt wearing course; and proven techniques for PSM mixing and base layer construction.

  10. Breaking/cracking and seating concrete pavements. Final report

    SciTech Connect

    Thompson, M.R.

    1989-03-01

    This synthesis will be of interest to pavement designers, maintenance engineers, and others interested in reducing reflection cracking of asphalt overlays on portland cement concrete (PCC) pavement. Information is presented on the technique of breaking or cracking of the concrete pavement into small segments before overlaying with asphalt concrete. Asphalt concrete overlays on existing PCC pavements are subject to reflection cracking induced by thermal movements of PCC pavement. The report of the Transportation Research Board discusses the technique of breaking/cracking and seating of the existing PCC before an overlay as a means to reduce or eliminate reflection cracking.

  11. Quantitative analysis of microtubule orientation in interdigitated leaf pavement cells.

    PubMed

    Akita, Kae; Higaki, Takumi; Kutsuna, Natsumaro; Hasezawa, Seiichiro

    2015-01-01

    Leaf pavement cells are shaped like a jigsaw puzzle in most dicotyledon species. Molecular genetic studies have identified several genes required for pavement cells morphogenesis and proposed that microtubules play crucial roles in the interdigitation of pavement cells. In this study, we performed quantitative analysis of cortical microtubule orientation in leaf pavement cells in Arabidopsis thaliana. We captured confocal images of cortical microtubules in cotyledon leaf epidermis expressing GFP-tubulinβ and quantitatively evaluated the microtubule orientations relative to the pavement cell growth axis using original image processing techniques. Our results showed that microtubules kept parallel orientations to the growth axis during pavement cell growth. In addition, we showed that immersion treatment of seed cotyledons in solutions containing tubulin polymerization and depolymerization inhibitors decreased pavement cell complexity. Treatment with oryzalin and colchicine inhibited the symmetric division of guard mother cells. PMID:26039484

  12. Studies of the effect of aging of ``quiet'' pavements on tire/pavement noise

    NASA Astrophysics Data System (ADS)

    Reyff, James A.; Donavan, Paul

    2005-09-01

    One of the issues with using quieter pavements to abate traffic noise is their continued acoustic performance over the life cycle of the surface. Aging effects can be assessed in two manners: (1) long term monitoring of the noise performance of an individual section of roadway; (2) measurement of multiple sections of pavement of the same construction, but different ages. Long term monitoring of Interstate 80 near Davis (I-80 Davis) began in 1998, just prior to the placement of a dense graded leveling course and open graded asphalt overlay. The pavement surface is now approaching 7 years old and continues to show a traffic noise reduction of about 5 dBA over the existing condition. As support of the Arizona Quiet Pavement Program (QPPP), similarly constructed sections of asphalt rubber friction course (ARFC) on Arizona's interstate highways were measured for tire/pavement performance using the close proximity (CPX) method and the on-board sound intensity method. The construction dates for the pavements ranged from 1988 to 1999. The total range in noise level was 7 dB with some indication of degrading performance with age.

  13. Permeable pavement research – Edison, New Jersey

    EPA Science Inventory

    These are the slides for the New York City Concrete Promotional Council Pervious Concrete Seminar presentation. The basis for the project, the monitoring design and some preliminary monitoring data from the permeable pavement parking lot at the Edison Environmental Center are pre...

  14. Pavement management and weigh-in-motion. Transportation research record

    SciTech Connect

    Cation, K.A.; Shahin, M.Y.; Scullion, T.; Lytton, R.L.; Butt, A.A.

    1987-01-01

    The 15 papers in the report deal with the following areas: development of a preventive maintenance algorithm for use in pavement-management systems; pavement-performance prediction model using the Markov Process; roadway modeling and data conversion for a transportation-facilities information system; development of a methodology to estimate pavement maintenance and repair costs for different ranges of pavement-condition index; new techniques for modeling pavement deterioration; pavement management at the local government level; a comprehensive ranking system for local-agency pavement management; expert system as a part of pavement management; MAPCON: a pavement-evaluation data-analysis computer system; a microcomputer procedure to analyze axle load limits and pavement damage responsibility; selected results from the first three years of the Oregon automatic monitoring demonstration project; automated acquisition of truck-tire pressure data; calibration and accuracy testing of weigh-in-motion systems; accuracy and tolerances of weigh-in-motion systems; on-site calibration of weigh-in-motion systems.

  15. Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

    PubMed Central

    Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S.; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

  16. MODELING PAVEMENT DETERIORATION PROCESSES BY POISSON HIDDEN MARKOV MODELS

    NASA Astrophysics Data System (ADS)

    Nam, Le Thanh; Kaito, Kiyoyuki; Kobayashi, Kiyoshi; Okizuka, Ryosuke

    In pavement management, it is important to estimate lifecycle cost, which is composed of the expenses for repairing local damages, including potholes, and repairing and rehabilitating the surface and base layers of pavements, including overlays. In this study, a model is produced under the assumption that the deterioration process of pavement is a complex one that includes local damages, which occur frequently, and the deterioration of the surface and base layers of pavement, which progresses slowly. The variation in pavement soundness is expressed by the Markov deterioration model and the Poisson hidden Markov deterioration model, in which the frequency of local damage depends on the distribution of pavement soundness, is formulated. In addition, the authors suggest a model estimation method using the Markov Chain Monte Carlo (MCMC) method, and attempt to demonstrate the applicability of the proposed Poisson hidden Markov deterioration model by studying concrete application cases.

  17. Hybrid green permeable pave with hexagonal modular pavement systems

    NASA Astrophysics Data System (ADS)

    Rashid, M. A.; Abustan, I.; Hamzah, M. O.

    2013-06-01

    Modular permeable pavements are alternatives to the traditional impervious asphalt and concrete pavements. Pervious pore spaces in the surface allow for water to infiltrate into the pavement during rainfall events. As of their ability to allow water to quickly infiltrate through the surface, modular permeable pavements allow for reductions in runoff quantity and peak runoff rates. Even in areas where the underlying soil is not ideal for modular permeable pavements, the installation of under drains has still been shown to reflect these reductions. Modular permeable pavements have been regarded as an effective tool in helping with stormwater control. It also affects the water quality of stormwater runoff. Places using modular permeable pavement has been shown to cause a significant decrease in several heavy metal concentrations as well as suspended solids. Removal rates are dependent upon the material used for the pavers and sub-base material, as well as the surface void space. Most heavy metals are captured in the top layers of the void space fill media. Permeable pavements are now considered an effective BMP for reducing stormwater runoff volume and peak flow. This study examines the extent to which such combined pavement systems are capable of handling load from the vehicles. Experimental investigation were undertaken to quantify the compressive characteristics of the modular. Results shows impressive results of achieving high safety factor for daily life vehicles.

  18. Smart pavement sensor based on thermoelectricity power

    NASA Astrophysics Data System (ADS)

    Yu, Xiong; Zhang, Bin; Tao, Junliang; Liu, Zhen

    2010-04-01

    The aging infrastructure requires a proactive strategy to ensure their functionality and performance. Innovative sensors are needed to develop infrastructures that are intelligent and adaptive. A power supply strategy is among the crucial components to reduce the instrument cost and to ensure the long term function of these embedded sensors. This paper introduces the results of a preliminary study on using thermo-electricity generation to power sensors. This presents an innovative strategy for long term monitoring of pavement performance.

  19. Automatic inspection of pavement cracking distress

    NASA Astrophysics Data System (ADS)

    Xu, B.; Huang, Y.

    2005-08-01

    This paper presents the image-processing algorithm customized for high-speed, real-time inspection of pavement cracking. In the algorithm, a pavement image is divided into grid cells of 8x8 pixels and each cell is classified as a non-crack or crack cell using the grayscale information of the border pixels. Whether a crack cell can be regarded as a basic element (or seed) depends on its contrast to the neighboring cells. A number of crack seeds can be called a crack cluster if they fall on a linear string. A crack cluster corresponds to a dark strip in the original image that may or may not be a section of a real crack. Additional conditions to verify a crack cluster include the requirements in the contrast, width and length of the strip. If verified crack clusters are oriented in similar directions, they will be joined to become one crack. Because many operations are performed on crack seeds rather than on the original image, crack detection can be executed simultaneously when the frame grabber is forming a new image, permitting real-time, online pavement survey. The trial test results show a good repeatability and accuracy when multiple surveys were conducted at different driving conditions.

  20. Automatic inspection of pavement cracking distress

    NASA Astrophysics Data System (ADS)

    Huang, Yaxiong; Xu, Bugao

    2006-01-01

    We present an image processing algorithm customized for high-speed, real-time inspection of pavement cracking. In the algorithm, a pavement image is divided into grid cells of 8×8 pixels, and each cell is classified as a noncrack or crack cell using the grayscale information of the border pixels. Whether a crack cell can be regarded as a basic element (or seed) depends on its contrast to the neighboring cells. A number of crack seeds can be called a crack cluster if they fall on a linear string. A crack cluster corresponds to a dark strip in the original image that may or may not be a section of a real crack. Additional conditions to verify a crack cluster include the requirements in the contrast, width, and length of the strip. If verified crack clusters are oriented in similar directions, they will be joined to become one crack. Because many operations are performed on crack seeds rather than on the original image, crack detection can be executed simultaneously when the frame grabber is forming a new image, permitting real-time, online pavement surveys. The trial test results show a good repeatability and accuracy when multiple surveys were conducted at different driving conditions.

  1. Permeable Pavement Research at the Edison Environmental Center

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditio...

  2. Development of a Portable Pavement Thickness/Density Meter (PTDM)

    NASA Astrophysics Data System (ADS)

    Maser, K. R.

    2002-08-01

    The Pavement Thickness/Density Meter (PTDM) concept developed in this research represents a new and innovative method for automatically determining pavement thickness and density. Pavement thickness and pavement density are two key variables that determine the future life and performance of asphalt pavement. In many cases, due to variations in placement conditions, the actual in-place thickness and density can vary considerably from specifications. Current testing methods based on coring are time consuming and do not provide adequate coverage. The PTDM system provides a means for quickly obtaining complete thickness/density coverage assessment of the pavement. The device is transportable and easily operated with limited training. It provides continuous data, in the form of profiles of the pavement thickness and density as a function of distance along the pavement. The method is safe, since it is based on low-powered pulsed electromagnetic waves. The key technological innovations required for the development of the PTDM are (1) the implementation of small and more portable components, particularly the transmitting antenna; (2) the implementation of software which automatically produces the readings that will be directly displayed for the operator; and (3) the packaging of all of these components in a small portable device that can be easily used and handled as a routine piece of field test equipment. The work carried out under this program has successfully achieved objectives (1) and (2).

  3. Nutrient Infiltrate Concentrations from Three Permeable Pavement Types

    EPA Science Inventory

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha...

  4. Permeable pavement monitoring at the Edison Environmental Center demonstration site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  5. Permeable pavement demonstration at the Edison Environmental Center

    EPA Science Inventory

    There are few studies of full-scale, outdoor, replicated, functioning pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are nec...

  6. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  7. Permeable pavement demonstration at the Edison Environmental Center (Hartford, CT)

    EPA Science Inventory

    In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

  8. Permeable pavement demonstration site at Edison Environmental Center (Presentation)

    EPA Science Inventory

    There are few studies of full-scale, outdoor, replicated, working pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are necessa...

  9. Permeable Pavement Demonstration at the Edison Environmental Center (Hartford)

    EPA Science Inventory

    In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

  10. Full-Depth Asphalt Pavements for Parking Lots and Driveways.

    ERIC Educational Resources Information Center

    Asphalt Inst., College Park, MD.

    The latest information for designing full-depth asphalt pavements for parking lots and driveways is covered in relationship to the continued increase in vehicle registration. It is based on The Asphalt Institute's Thickness Design Manual, Series No. 1 (MS-1), Seventh Edition, which covers all aspects of asphalt pavement thickness design in detail,…

  11. Modeling the Hydrologic Processes of a Permeable Pavement System

    EPA Science Inventory

    A permeable pavement system can capture stormwater to reduce runoff volume and flow rate, improve onsite groundwater recharge, and enhance pollutant controls within the site. A new unit process model for evaluating the hydrologic performance of a permeable pavement system has be...

  12. Monitoring asphalt pavement damages using remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Mettas, Christodoulos; Themistocleous, Kyriacos; Neocleous, Kyriacos; Christofe, Andreas; Pilakoutas, Kypros; Hadjimitsis, Diofantos

    2015-06-01

    One of the main issues in the maintenance plans of road agencies or governmental organizations is the early detection of damaged asphalt pavements. The development of a smart and non-destructive systematic technique for monitoring damaged asphalt pavements is considered a main priority to fill this gap. During the 1970's, remote sensing was used to map road surface distress, while during the last decade, remote sensing became more advanced, thereby assisting in the evolution of the identification and mapping of roads. Various techniques were used in order to explore condition, age, weaknesses and imperfections of asphalted pavements. These methods were fairly successful in the classification of asphalted surfaces and in the detection of some of their characteristics. This paper explores the state of the art of using remote sensing techniques for monitoring damaged pavements and some typical spectral profiles of various asphalt pavements in Cyprus area acquired using the SVC1024 field spectroradiometer.

  13. The vesicular layer and carbonate collars of desert soils and pavements: formation, age and relation to climate change

    NASA Astrophysics Data System (ADS)

    McFadden, Leslie D.; McDonald, Eric V.; Wells, Stephen G.; Anderson, Kirk; Quade, Jay; Forman, Steven L.

    1998-08-01

    The vesicular, fine-grained A horizon (Av) is the widespread, ubiquitous surficial horizon of desert soils in diverse landforms and parent materials of varying ages. Now known to form mostly through accumulation of eolian dust, recent studies show that dust accumulation and concomitant soil development are genetically linked to stone pavement formation. Changes in the magnitude of eolian activity and effective leaching related to Quaternary climatic changes are also hypothesized to have influenced the evolution of the Av horizon. Numerical modeling, geochronologic, and field/laboratory studies elucidate the nature of pedogenic processes controlling compositional evolution of Av, how the changing Av horizon increasingly influences soil infiltration and carbonate translocation and accumulation, and the control that clasts of the evolving pavement exert on pedogenic processes. Results of a model that determines soil bulk chemical composition based on mixing of estimated proportions of externally derived (eolian) material and parent materials imply that the evolution of the soil bulk composition is strongly influenced by Av horizon formation. The early development of a weakly to moderately developed Av horizon directly over gravelly parent material in late and middle Holocene soils moderately influences soil infiltration, but significant leaching of very soluble materials and some carbonate in dust are permitted. In older, Pleistocene soils, however, the texturally more mature Av and underlying, cumulic nongravelly horizons more strongly limit the rate and depth of leaching, and soil bulk composition therefore more closely approximates a simple mixture of dust and parent material. Other aspects of Av horizon development and its relations to the pavement are evaluated through studies of pavement clasts with coatings of soil carbonate, referred to as carbonate collars. Development of a numerical model that integrates soil hydrology, a CO 2 production-diffusion model

  14. Tire Footprint Affects Hydroplaning On Wet Pavement

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1989-01-01

    Recent investigations of tire hydroplaning at highway speeds reveal, in addition to inflation pressure, tire-footprint aspect ratio (FAR), defined as width divided by length of tire surface in contact with pavement, significantly influences speed at which dynamic hydroplaning begins. Tire speeds and forces developed during tests of up to 65 mi/h (105 km/h) were monitored on flooded test surface to identify development of hydroplaning. Study focused on automotive tires because FAR's of automotive tires vary more than those of aircraft tires.

  15. Utilization of Advanced Diagnostic Methods for Texture and Rut Depth Analysis on a Testing Pavement Section

    NASA Astrophysics Data System (ADS)

    Slabej, Martin; Grinč, Michal; Kotek, Peter; Kováč, Matúš; Decký, Martin

    2015-05-01

    Qualitative characteristics of pavement in wide range reflects the pavement serviceability, which is a summary of the characteristics of the pavement, providing a fast, smooth, economical and especially safe driving of motor-vehicles. The target factor of pavement serviceability and safety of roads represents the quality of their surface properties. In the framework of research activities performed in the Research Centre founded under the auspices of University of Žilina, individual parameters of pavement serviceability were monitored by pavement surface scanning. This paper describes the creation of a 3D - road surface model and its analysis and evaluation from the viewpoint of two pavement serviceability parameters - the rut depth and texture. Measurements were performed on an experimental pavement section used contemporary in an Accelerated Pavement Testing experiment. The long-term goal is to ascertain functions predicting degradation of these two pavement serviceability parameters.

  16. Automated management for pavement inspection system (AMPIS)

    NASA Astrophysics Data System (ADS)

    Chung, Hung Chi; Girardello, Roberto; Soeller, Tony; Shinozuka, Masanobu

    2003-08-01

    An automated in-situ road surface distress surveying and management system, AMPIS, has been developed on the basis of video images within the framework of GIS software. Video image processing techniques are introduced to acquire, process and analyze the road surface images obtained from a moving vehicle. ArcGIS platform is used to integrate the routines of image processing and spatial analysis in handling the full-scale metropolitan highway surface distress detection and data fusion/management. This makes it possible to present user-friendly interfaces in GIS and to provide efficient visualizations of surveyed results not only for the use of transportation engineers to manage road surveying documentations, data acquisition, analysis and management, but also for financial officials to plan maintenance and repair programs and further evaluate the socio-economic impacts of highway degradation and deterioration. A review performed in this study on fundamental principle of Pavement Management System (PMS) and its implementation indicates that the proposed approach of using GIS concept and its tools for PMS application will reshape PMS into a new information technology-based system providing a convenient and efficient pavement inspection and management.

  17. Pavement cracking measurements using 3D laser-scan images

    NASA Astrophysics Data System (ADS)

    Ouyang, W.; Xu, B.

    2013-10-01

    Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel-1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s-1, allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions.

  18. Variability of pavement noise benefit by vehicle type

    NASA Astrophysics Data System (ADS)

    Rochat, Judith L.; Read, David R.

    2005-09-01

    The Volpe Center Acoustics Facility, in support of the California Department of Transportation (Caltrans), is participating in a long-term study to assess several types of pavement for the purpose of noise abatement. On a four-mile stretch of a two-lane highway in Southern California, several asphalt pavement overlays are being examined. Acoustical, meteorological, and traffic data are collected in each pavement overlay section, where microphones are deployed at multiple distances and heights. Single vehicle pass-by events are recorded primarily for three vehicle types: automobiles, medium trucks, and heavy trucks. Data are analyzed to determine the noise benefit of each pavement as compared to the reference dense-graded asphaltic concrete (DGAC); this includes a modified Statistical Pass-By Index as well as average Lmax values for each vehicle type. In addition, 1/3-octave band data are examined. Automobiles and heavy trucks are the focus of this paper, where benefits due to pavement will be presented for three pavement types: open-graded asphaltic concrete (OGAC) of 75 mm thickness, open-graded asphaltic concrete (OGAC) of 30 mm thickness, and rubberized asphaltic concrete, Type O (open) (RAC) of 30 mm thickness. Average Lmax values and spectral data show that noise benefits due to pavement can vary by vehicle type.

  19. Evaluation of base widening methods on flexible pavements in Wyoming

    NASA Astrophysics Data System (ADS)

    Offei, Edward

    The surface transportation system forms the biggest infrastructure investment in the United States of which the roadway pavement is an integral part. Maintaining the roadways can involve rehabilitation in the form of widening, which requires a longitudinal joint between the existing and new pavement sections to accommodate wider travel lanes, additional travel lanes or modification to shoulder widths. Several methods are utilized for the joint construction between the existing and new pavement sections including vertical, tapered and stepped joints. The objective of this research is to develop a formal recommendation for the preferred joint construction method that provides the best base layer support for the state of Wyoming. Field collection of Dynamic Cone Penetrometer (DCP) data, Falling Weight Deflectometer (FWD) data, base samples for gradation and moisture content were conducted on 28 existing and 4 newly constructed pavement widening projects. A survey of constructability issues on widening projects as experienced by WYDOT engineers was undertaken. Costs of each joint type were compared as well. Results of the analyses indicate that the tapered joint type showed relatively better pavement strength compared to the vertical joint type and could be the preferred joint construction method. The tapered joint type also showed significant base material savings than the vertical joint type. The vertical joint has an 18% increase in cost compared to the tapered joint. This research is intended to provide information and/or recommendation to state policy makers as to which of the base widening joint techniques (vertical, tapered, stepped) for flexible pavement provides better pavement performance.

  20. Research on pavement roughness based on the laser triangulation

    NASA Astrophysics Data System (ADS)

    Chen, Wenxue; Ni, Zhibin; Hu, Xinhan; Lu, Xiaofeng

    2016-06-01

    Pavement roughness is one of the most important factors for appraising highway construction. In this paper, we choose the laser triangulation to measure pavement roughness. The principle and configuration of laser triangulation are introduced. Based on this technology, the pavement roughness of a road surface is measured. The measurement results are given in this paper. The measurement range of this system is 50 μm. The measurement error of this technology is analyzed. This technology has an important significance to appraise the quality of highway after completion of the workload.

  1. Evaluation of a new construction pavement section using the mechanistic-empirical pavement design guide

    NASA Astrophysics Data System (ADS)

    Lowe, Justin

    The AASHTO Mechanistic-Empirical Design Guide (MEPDG) is one of several "next generation" pavement design approaches intended to address limitations of older empirical methods. This research investigated the capabilities and performance of the MEPDG through analyses of an empirically-designed section of NH Route 16, which the New Hampshire Department of Transportation (NHDOT) indicated may be under-designed. MEPDG distress predictions indicate that the pavement section should achieve a service life of at least 10 years. This was supported by the fatigue analysis of the base course, which also indicated that the pavement may have been damaged by traffic loads prior to the completion of the surface course. During this research, a number of limitations and model behaviors of the MEPDG were observed, some with significant importance to this analysis and to future projects within New Hampshire. Because implementation and full realization of the MEPDG requires significant investment, the results of this research should be considered before undertaking steps towards adoption of the software.

  2. Permeable Pavement Demonstration at the Edison Environmental Center - Poster

    EPA Science Inventory

    Poster for the SAB Review detailing the porous pavement parking lot project. The poster describes the design of the parking lot, the research components that were incorporated into the design, and the monitoring plan.

  3. ANALYSIS OF GROUP MAINTENANCE STRATEGY -ROAD PAVEMENT AND SEWERAGE PIPES-

    NASA Astrophysics Data System (ADS)

    Tanimoto, Keishi; Sugimoto, Yasuaki; Miyamoto, Shinya; Nada, Hideki; Hosoi, Yoshihiko

    Recently, it is critical to manage deteriorating sewerage and road facilities efficiently and strategically. Since the sewerage pipes are mostly installed under road pavement, the works for the replacement of the sewerage pipes are partially common to the works for the road. This means that the replacement cost can be saved by coordinating the timing of the replacements by sewerage pipe and road pavement. The purpose of the study is to develop the model based on Markov decision process to derive the optimal group maintenance policy so as to minimize lifecycle cost. Then the model is applied to case study area and demonstrated to estimate the lifecycle cost using statistical data such as pipe replacement cost, road pavement rehabilitation cost, and state of deterioration of pipes and road pavement.

  4. Latex improvement of recycled asphalt pavement

    NASA Astrophysics Data System (ADS)

    Drennon, C.

    1982-08-01

    The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

  5. Evaluating exposure of pedestrians to airborne contaminants associated with non-potable water use for pavement cleaning.

    PubMed

    Seidl, M; Da, G; Ausset, P; Haenn, S; Géhin, E; Moulin, L

    2016-04-01

    Climate change and increasing demography press local authorities to look after affordable water resources and replacement of drinking water for city necessities like street and pavement cleaning by more available raw water. Though, the substitution of drinking by non-drinking resources demands the evaluation of sanitary hazards. This article aims therefore to evaluate the contribution of cleaning water to the overall exposure of city dwellers in case of wet pavement cleaning using crossed physical, chemical and biological approaches. The result of tracer experiments with fluorescein show that liquid water content of the cleaning aerosol produced is about 0.24 g m(-3), rending possible a fast estimation of exposure levels. In situ analysis of the aerosol particles indicates a significant increase in particle number concentration and particle diameter, though without change in particle composition. The conventional bacterial analysis using total coliforms as tracer suggests that an important part of the contamination is issued from the pavement. The qPCR results show a more than 20-fold increase of background genome concentration for Escherichia coli and 10-fold increase for Enterococcus but a negligible contribution of the cleaning water. The fluorescence analysis of the cleaning aerosol confirms the above findings identifying pavement surface as the major contributor to aerosol organic load. The physical, chemical and microbiological approaches used make it possible to describe accurately the cleaning bioaerosol and to identify the existence of significantly higher levels of all parameters studied during the wet pavement cleaning. Though, the low level of contamination and the very short time of passage of pedestrian in the zone do not suggest a significant risk for the city dwellers. As the cleaning workers remain much longer in the impacted area, more attention should be paid to their chronic exposure. PMID:26233734

  6. Environmental assessment of pavement infrastructure: A systematic review.

    PubMed

    Inyim, Peeraya; Pereyra, Jose; Bienvenu, Michael; Mostafavi, Ali

    2016-07-01

    Through a critical review and systematic analysis of pavement life cycle assessment (LCA) studies published over the past two decades, this study shows that the available information regarding the environmental impacts of pavement infrastructure is not sufficient to determine what pavement type is more environmentally sustainable. Limitations and uncertainties related to data, system boundary and functional unit definitions, consideration of use and maintenance phase impacts, are identified as the main reasons for inconsistency of reported results in pavement LCA studies. The study outcomes also highlight the need for advancement of knowledge pertaining to: (1) utilization of performance-adjusted functional units, (2) accurate estimation of use, maintenance, and end-of-life impacts, (3) incorporation of the dynamic and uncertain nature of pavement condition performance in impact assessment; (4) development of region-specific inventory data for impact estimation; and (5) consideration of a standard set of impact categories for comparison of environmental performance of different pavement types. Advancing the knowledge in these areas is critical in providing consistent and reliable results to inform decision-making toward more sustainable roadway infrastructure. PMID:27045541

  7. Urban pavement surface temperature. Comparison of numerical and statistical approach

    NASA Astrophysics Data System (ADS)

    Marchetti, Mario; Khalifa, Abderrahmen; Bues, Michel; Bouilloud, Ludovic; Martin, Eric; Chancibaut, Katia

    2015-04-01

    The forecast of pavement surface temperature is very specific in the context of urban winter maintenance. to manage snow plowing and salting of roads. Such forecast mainly relies on numerical models based on a description of the energy balance between the atmosphere, the buildings and the pavement, with a canyon configuration. Nevertheless, there is a specific need in the physical description and the numerical implementation of the traffic in the energy flux balance. This traffic was originally considered as a constant. Many changes were performed in a numerical model to describe as accurately as possible the traffic effects on this urban energy balance, such as tires friction, pavement-air exchange coefficient, and infrared flux neat balance. Some experiments based on infrared thermography and radiometry were then conducted to quantify the effect fo traffic on urban pavement surface. Based on meteorological data, corresponding pavement temperature forecast were calculated and were compared with fiels measurements. Results indicated a good agreement between the forecast from the numerical model based on this energy balance approach. A complementary forecast approach based on principal component analysis (PCA) and partial least-square regression (PLS) was also developed, with data from thermal mapping usng infrared radiometry. The forecast of pavement surface temperature with air temperature was obtained in the specific case of urban configurtation, and considering traffic into measurements used for the statistical analysis. A comparison between results from the numerical model based on energy balance, and PCA/PLS was then conducted, indicating the advantages and limits of each approach.

  8. Cloud Impacts on Pavement Temperature in Energy Balance Models

    NASA Astrophysics Data System (ADS)

    Walker, C. L.

    2013-12-01

    Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with road safety. Pavement temperature is an important variable when considering vehicle response to various weather conditions. A complex, yet direct relationship exists between tire and pavement temperatures. Literature has shown that as tire temperature increases, friction decreases which affects vehicle performance. Many forecast systems suffer from inaccurate radiation forecasts resulting in part from the inability to model different types of clouds and their influence on radiation. This research focused on forecast improvement by determining how cloud type impacts the amount of shortwave radiation reaching the surface and subsequent pavement temperatures. The study region was the Great Plains where surface solar radiation data were obtained from the High Plains Regional Climate Center's Automated Weather Data Network stations. Road pavement temperature data were obtained from the Meteorological Assimilation Data Ingest System. Cloud properties and radiative transfer quantities were obtained from the Clouds and Earth's Radiant Energy System mission via Aqua and Terra Moderate Resolution Imaging Spectroradiometer satellite products. An additional cloud data set was incorporated from the Naval Research Laboratory Cloud Classification algorithm. Statistical analyses using a modified nearest neighbor approach were first performed relating shortwave radiation variability with road pavement temperature fluctuations. Then statistical associations were determined between the shortwave radiation and cloud property data sets. Preliminary results suggest that substantial pavement forecasting improvement is possible with the inclusion of cloud-specific information. Future model sensitivity testing seeks to quantify the magnitude of forecast improvement.

  9. Influence of pavement condition on horizontal curve safety.

    PubMed

    Buddhavarapu, Prasad; Banerjee, Ambarish; Prozzi, Jorge A

    2013-03-01

    Crash statistics suggest that horizontal curves are the most vulnerable sites for crash occurrence. These crashes are often severe and many involve at least some level of injury due to the nature of the collisions. Ensuring the desired pavement surface condition is one potentially effective strategy to reduce the occurrence of severe accidents on horizontal curves. This study sought to develop crash injury severity models by integrating crash and pavement surface condition databases. It focuses on developing a causal relationship between pavement condition indices and severity level of crashes occurring on two-lane horizontal curves in Texas. In addition, it examines the suitability of the existing Skid Index for safety maintenance of two-lane curves. Significant correlation is evident between pavement condition and crash injury severity on two-lane undivided horizontal curves in Texas. Probability of a crash becoming fatal is appreciably sensitive to certain pavement indices. Data suggested that road facilities providing a smoother and more comfortable ride are vulnerable to severe crashes on horizontal curves. In addition, the study found that longitudinal skid measurement barely correlates with injury severity of crashes occurring on curved portions. The study recommends exploring the option of incorporating lateral friction measurement into Pavement Management System (PMS) databases specifically at curved road segments. PMID:23298704

  10. Recycled materials in asphalt pavements. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-05-01

    The bibliography contains citations concerning the recycling of asphalt pavement materials, and the use of other recycled materials to manufacture asphalt pavement. Articles discuss methods used for recycling bituminous pavement including hot-mix and cold-mix. Materials used to improve recycled pavement, and recycled materials used in asphalt pavement include latexes, rubber scrap such as tires, glass shards, concretes, dusts, waste oils, roofing wastes, sulfur, and metal refining sludges. Testing and evaluation of recycled pavements both in laboratories and in test cases are considered. (Contains a minimum of 160 citations and includes a subject term index and title list.)

  11. Post-Glacial Ant Generated Desert Pavements in Southeastern Oregon

    NASA Astrophysics Data System (ADS)

    Leonard, K. C.

    2001-12-01

    Desert pavements typically require thousands to tens of thousands of years to reach a high level of development. In a pluvial lake valley in Southeastern Oregon I have observed harvester ants creating desert pavement-like features in less than two months. The summer lake basin is a fairly simple sedimentary system. In the eastern half of the basin, the basaltic bedrock is buried under tens of meters of alluvial deposits which lie beneath an approximately ten meter thick dune sheet. The dune sands are noticably different in grainsize and chemistry than the fine component of the alluvial deposits. The dunes began to form at the end of the last pluvial interval (Allison 1980) and continue to be active today. Roughly one fourth of the total area of the dune sheet is mantled with desert pavement, consisting of very coarse sand and fine pebbles (1-8 mm diameter). The dune sand is very fine grained with a considerable amount of silt and minimal clay. It forms thin (2-20 cm thick) well developed Av horizons beneath the desert pavement. Owyhee harvester ants (Pogonomyrmex owyheei) in the area use pebbles of the same size and petrology as the desert pavements to construct their hills. For the ants the closest source of these pebbles is often the alluvium, ten meters below the anthill, rather than in a desert pavement deposit at some distance away overland. An experiment conducted between June and August 1999 demonstrated that the ants rebuild their hills with newly excavated pebbles. When the colonies die off after 5-25 years, the pebbles are stranded at the surface. Processes such as those described by Haff and Werner (1996), where jackrabbits and birds were observed kicking desert pavement clasts aross the ground serve to redistribute the pebbles across the surface of the sand dunes. The sand dunes have been forming over an 8000 year period. Based on anthill-regrowth measurements, the lifespan of an individual colony of harvester ants leads to the excavation of only enough

  12. STUDY ON FLOOD CONTROL PROPERTIES OF PERMEABLE PAVEMENT USING SATURATED-UNSATURATED SEEPAGE ANALYSIS

    NASA Astrophysics Data System (ADS)

    Yano, Takao; Nishiyama, Satoshi; Ohnishi, Yuzo; Nakashima, Shinichiro; Moriishi, Kazushi; Wada, Minoru

    The rainfall storage and infiltration facility of permeable pavement have been attracted attention as a control measure of flood and an environmental improvement measure in urban areas. However, rainfall infiltration of permeable pavement is unsteady flow and strongly dependent on the behavior of unsaturated zones in the pavement. Moreover, the wet condition of subbase course also has a great influence on the rainfall infiltration of the pavement. That's why previous studies have not made clear the precise the facility of permeable pavement as a flood control. In this paper, experimental studies and simulated analyses were performed to measure the overflow from the pavement under various conditions of rainfall intensities and estimate the rainfall infiltration of the pavement using the measurement data and unsaturated infiltration characteristics of porous asphalt materials. It is clear that this study shows the methods to have a quantitative estimation of the rainfall storage and infiltration facility of permeable pavement.

  13. Evaluation of Three Porous Pavement Systems in a Newly Constructed Parking Lot

    EPA Science Inventory

    This project examines porous pavement systems in a newly constructed parking lot next to Building 205 at the Edison Environmental Center. Porous pavement systems are one means of promoting environmental sustainability through stormwater runoff reduction. This project examines t...

  14. Stormwater quality of spring-summer-fall effluent from three partial-infiltration permeable pavement systems and conventional asphalt pavement.

    PubMed

    Drake, Jennifer; Bradford, Andrea; Van Seters, Tim

    2014-06-15

    This study examined the spring, summer and fall water quality performance of three partial-infiltration permeable pavement (PP) systems and a conventional asphalt pavement in Ontario. The study, conducted between 2010 and 2012, compared the water quality of effluent from two Interlocking Permeable Concrete Pavements (AquaPave(®) and Eco-Optiloc(®)) and a Hydromedia(®) Pervious Concrete pavement with runoff from an Asphalt control pavement. The usage of permeable pavements can mitigate the impact of urbanization on receiving surface water systems through quantity control and stormwater treatment. The PP systems provided excellent stormwater treatment for petroleum hydrocarbons, total suspended solids, metals (copper, iron, manganese and zinc) and nutrients (total-nitrogen and total-phosphorus) by reducing event mean concentrations (EMC) as well as total pollutant loadings. The PPs significantly reduced the concentration and loading of ammonia (NH4(+)+NH3), nitrite (NO2(-)) and organic-nitrogen (Org-N) but increased the concentration and loading of nitrate (NO3(-)). The PP systems had mixed performances for the treatment of phosphate (PO4(3-)). The PP systems increased the concentration of sodium (Na) and chloride (Cl) but EMCs remained well below recommended levels for drinking water quality. Relative to the observed runoff, winter road salt was released more slowly from the PP systems resulting in elevated spring and early-summer Cl and Na concentrations in effluent. PP materials were found to introduce dissolved solids into the infiltrating stormwater. The release of these pollutants was verified by additional laboratory scale testing of the individual pavement and aggregate materials at the University of Guelph. Pollutant concentrations were greatest during the first few months after construction and declined rapidly over the course of the study. PMID:24681366

  15. 76 FR 67018 - Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather Information Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Federal Aviation Administration Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather... of In-Pavement Stationary Runway Weather Information Systems. SUMMARY: Projects funded under the... Active or Passive In- Pavement Stationary Runway Weather Information Systems that meet the...

  16. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Federal lands pavement management system (PMS). 970.208... Federal lands pavement management system (PMS). In addition to the requirements provided in § 970.204, the...) An inventory of the physical pavement features including the number of lanes, length, width,...

  17. Stabilized fiber-reinforced pavement base course with recycled aggregate

    NASA Astrophysics Data System (ADS)

    Sobhan, Khaled

    This study evaluates the benefits to be gained by using a composite highway base course material consisting of recycled crushed concrete aggregate, portland cement, fly ash, and a modest amount of reinforcing fibers. The primary objectives of this research were to (a) quantify the improvement that is obtained by adding fibers to a lean concrete composite (made from recycled aggregate and low quantities of Portland cement and/or fly ash), (b) evaluate the mechanical behavior of such a composite base course material under both static and repeated loads, and (c) utilize the laboratory-determined properties with a mechanistic design method to assess the potential advantages. The split tensile strength of a stabilized recycled aggregate base course material was found to be exponentially related to the compacted dry density of the mix. A lean mix containing 4% cement and 4% fly ash (by weight) develops sufficient unconfined compressive, split tensile, and flexural strengths to be used as a high quality stabilized base course. The addition of 4% (by weight) of hooked-end steel fibers significantly enhances the post-peak load-deformation response of the composite in both indirect tension and static flexure. The flexural fatigue behavior of the 4% cement-4% fly ash mix is comparable to all commonly used stabilized materials, including regular concrete; the inclusion of 4% hooked-end fibers to this mix significantly improves its resistance to fatigue failure. The resilient moduli of stabilized recycled aggregate in flexure are comparable to the values obtained for traditional soil-cement mixes. In general, the fibers are effective in retarding the rate of fatigue damage accumulation, which is quantified in terms of a damage index defined by an energy-based approach. The thickness design curves for a stabilized recycled aggregate base course, as developed by using an elastic layer approach, is shown to be in close agreement with a theoretical model (based on Westergaard

  18. Design prediction of pavement skid resistance from laboratory tests

    NASA Astrophysics Data System (ADS)

    Parcells, W. H.; Metheny, T. M.; Maag, R. G.

    1980-08-01

    Methods for preevaluating aggregates and paving mixtures so that predictions can be made covering skid resistance properties of proposed and in service pavement types are discussed. A correlation was established between the field testing using the data from the British Portable Tester and the Locked Wheel Pavement Friction Trailer at speeds of 40 and 55 mph. Core samples were extracted from the Locked Wheel Tester Skid Path and subjected to wear on the small wheel circular track with periodic surface friction testing. The final step was to remix and remold the cored pavement samples or make samples with new materials to obtain an 'as new' surface and again subject these samples to wear on the small wheel circular track with periodic testing.

  19. Rapid Inspection of Pavement Markings Using Mobile LIDAR Point Clouds

    NASA Astrophysics Data System (ADS)

    Zhang, Haocheng; Li, Jonathan; Cheng, Ming; Wang, Cheng

    2016-06-01

    This study aims at building a robust semi-automated pavement marking extraction workflow based on the use of mobile LiDAR point clouds. The proposed workflow consists of three components: preprocessing, extraction, and classification. In preprocessing, the mobile LiDAR point clouds are converted into the radiometrically corrected intensity imagery of the road surface. Then the pavement markings are automatically extracted with the intensity using a set of algorithms, including Otsu's thresholding, neighbor-counting filtering, and region growing. Finally, the extracted pavement markings are classified with the geometric parameters using a manually defined decision tree. Case studies are conducted using the mobile LiDAR dataset acquired in Xiamen (Fujian, China) with different road environments by the RIEGL VMX-450 system. The results demonstrated that the proposed workflow and our software tool can achieve 93% in completeness, 95% in correctness, and 94% in F-score when using Xiamen dataset.

  20. Low cost pavement marking materials based on plasticized sulfur

    NASA Astrophysics Data System (ADS)

    Dale, J. M.

    1982-04-01

    Pavement marking was made more cost effective by reducing the cost of the marking materials. A low cost marking material based on sulfur was developed. Elemental sulfur is a hard, brittle, crystalline material which, on heating, melts to a thin liquid that can be spray applied. If molten elemental sulfur is spray applied to the road as markings, it will on application solidify, crack and adhere poorly to the road. The first ten high speed trucks that ride over the markings will remove them. To make a useful sulfur based pavement marking material it was necessary to chemically modify (plasticize) the sulfur and mix it with fillers and pigments such that it had all of the characteristics desired of a pavement marking material. Yellow and white formulations were developed. For identification they were given the names YS-EIGHT and WS-EIGHT for the yellow and white formulations.

  1. Research of infrared laser based pavement imaging and crack detection

    NASA Astrophysics Data System (ADS)

    Hong, Hanyu; Wang, Shu; Zhang, Xiuhua; Jing, Genqiang

    2013-08-01

    Road crack detection is seriously affected by many factors in actual applications, such as some shadows, road signs, oil stains, high frequency noise and so on. Due to these factors, the current crack detection methods can not distinguish the cracks in complex scenes. In order to solve this problem, a novel method based on infrared laser pavement imaging is proposed. Firstly, single sensor laser pavement imaging system is adopted to obtain pavement images, high power laser line projector is well used to resist various shadows. Secondly, the crack extraction algorithm which has merged multiple features intelligently is proposed to extract crack information. In this step, the non-negative feature and contrast feature are used to extract the basic crack information, and circular projection based on linearity feature is applied to enhance the crack area and eliminate noise. A series of experiments have been performed to test the proposed method, which shows that the proposed automatic extraction method is effective and advanced.

  2. Thin, applied surfacing for improving skid resistance of concrete pavements

    NASA Astrophysics Data System (ADS)

    Scholer, C. F.

    1980-12-01

    The use of select aggregate in a thin wearing surface of portland cement mortar to prolone or restore a concrete pavement's ability to develop high friction was accomplished. Two fine aggregates, blast furnace slag and lightweight expanded shale were found to exhibit skid resistance greater than the other aggregates evaluated. The British polishing wheel was used in the laboratory evaluation of aggregate to simulate wear. The need for a method of restoring friction to a worn, but otherwise sound concrete pavement led to a field evaluation of several different techniques for placing a very thin overlay. The successful method was a broomed, very thin layer of mortar, 3 mm thick.

  3. Fatigue properties of rubber modified pavements. Final report

    SciTech Connect

    Raad, L.; Saboundjian, S.; Yuan, X.

    1995-05-01

    This report presents results of a study to determine the fatigue behavior of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements. Laboratory studies were conducted on field specimens using the flexural fatigue test in the controlled-displacement mode. Tests were performed at 72 deg F and 40 deg F. Tested materials include (1) conventional HMA with AC 2.5 and AC 5; (2) PlusRide RUMAC with AC 5; (3) asphalt-rubber concrete with AC 2.5 (wet Process); and (4) rubberized asphalt-rubber concrete with AC 2.5 (wet/dry process).

  4. Evaluation of multilayered pavement structures from measurements of surface waves

    USGS Publications Warehouse

    Ryden, N.; Lowe, M.J.S.; Cawley, P.; Park, C.B.

    2006-01-01

    A method is presented for evaluating the thickness and stiffness of multilayered pavement structures from guided waves measured at the surface. Data is collected with a light hammer as the source and an accelerometer as receiver, generating a synthetic receiver array. The top layer properties are evaluated with a Lamb wave analysis. Multiple layers are evaluated by matching a theoretical phase velocity spectrum to the measured spectrum. So far the method has been applied to the testing of pavements, but it may also be applicable in other fields such as ultrasonic testing of coated materials. ?? 2006 American Institute of Physics.

  5. About the sizes of elastomer particles in the asphalt concrete binder providing the maximum service life of pavements

    NASA Astrophysics Data System (ADS)

    Kaplan, A. M.; Chekunaev, N. I.

    2014-05-01

    It is noted that the durability of asphalt concrete pavements is determined by the time of the trunk cracks formation in the polymer-containing composites - in the modified by elastomers (e.g., by rubber) bitumenous binder of asphalt. Developed by the authors previously the theory of the cracks propagation in heterosystems [1] has allowed to investigate the problem of the cracks propagation in the rubber-bitumen composite. This investigations show that most effectively to prevente the trunk cracks formation in asphalt concrete can ultrafine rubber particles (150-750 nm) in a bitumenos binder of asphalt.

  6. Groove depth requirements for tine-textured rigid pavement 5: Durability of tine texturing on PCC pavements

    NASA Astrophysics Data System (ADS)

    Grady, J. E.; Chamberlin, W. P.

    1981-06-01

    The required depth for grooves on new tine textured concrete pavements in order to assure an adequate skid resistance over their entire design life is discussed. Measurements of texture depth and skid resistance, with both ribbed and smooth tires were made on 0 to 5 year-old New York pavements. Initial groove depth needs of 3/16 in. minimum were calculated from two values estimated from the study data: the minimum depth (0.050 in.) to assure adequate skid resistance with a minimally legal treaded tire, and the mean groove wear rate (0.013 in./million vehicle passes). Groove depth measurements on new concrete pavements and bridge decks indicated 21 an 14 percent compliance, respectively, with the proposed new standard of 3/16 in. minimum, and 60 and 44 percent compliance with the current standard of 2/16 in. minimum.

  7. Deterioration modeling for condition assessment of flexible pavements considering extreme weather events

    NASA Astrophysics Data System (ADS)

    Hashemi Tari, Yasamin; Shahini Shamsabadi, Salar; Birken, Ralf; Wang, Ming

    2015-04-01

    Accurate pavement management systems are essential for states' Department Of Transportation and roadway agencies to plan for cost-effective maintenance and repair (M and R) strategies. Pavement deterioration model is an imperative component of any pavement management system since the future budget and M and R plans would be developed based on the predicted pavement performance measures. It is crucial for the pavement deterioration models to consider the factors that significantly aggravate the pavement condition. While many studies have highlighted the impact of different environmental, load, and pavement's structure on the life cycle of the pavement, effect of extreme weather events such as Floods and Snow Storms have often been overlooked. In this study, a pavement deterioration model is proposed which would consider the effect of traffic loads, climate conditions, and extreme weather events. Climate, load and performance data has been compiled for over twenty years and for eight states using the Long Term Pavement Performance (LTPP) and National Oceanic and Atmospheric Administration (NOAA) databases. A stepwise regression approach is undertaken to quantify the effect of the extreme weather events, along with other influential factors on pavement performance in terms of International Roughness Index (IRI). Final results rendered more than 90% correlation with the quantified impact values of extreme weather events.

  8. Desert pavements and associated rock varnish in the Mojave Desert: How old can they be?

    NASA Astrophysics Data System (ADS)

    Quade, Jay

    2001-09-01

    Desert pavements are common features of arid landscapes and have been widely used as a relative age indicator of the geomorphic surfaces upon which they are developed. In this study I examined the patterns of pavement development as a function of elevation in the Mojave Desert as well as the causes for the gradual disappearance of pavement at high elevations. Pavement density, as measured by percentage of pebble coverage, decreases systematically with elevation gain by ˜3% per 100 m, from 95% coverage below 500 m to less than 60% at 1700 m. Plants appear to be the main agent of pavement disruption; plant density decreases as pavement density increases. Burrowing by rodents and crusting by cryptobiota also disrupt pavement development at higher elevation. During the last glacial maximum, plant communities were displaced 1000 1400 m downward in the Mojave Desert. Pavements today generally do not survive above the blackbush (Coleogyne ramossisma)-sagebrush (Artemisia tridentata) zone. Evidence from packrat middens shows that these and other plants typical of high elevations today grew as low as 300 400 m during the last glacial maximum. I suggest that during the last glacial maximum, desert pavements were confined to the lowest alluvial fans of Death Valley and adjoining low valleys. No alluvial desert pavements above ˜400 m in the region are older than the latest Pleistocene. By the same reasoning, desert varnish on desert pavements above 400 m may all be Holocene in age, except where developed on stable boulders.

  9. Functionality Enhancement of Industrialized Optical Fiber Sensors and System Developed for Full-Scale Pavement Monitoring

    PubMed Central

    Wang, Huaping; Liu, Wanqiu; He, Jianping; Xing, Xiaoying; Cao, Dandan; Gao, Xipeng; Hao, Xiaowei; Cheng, Hongwei; Zhou, Zhi

    2014-01-01

    Pavements always play a predominant role in transportation. Health monitoring of pavements is becoming more and more significant, as frequently suffering from cracks, rutting, and slippage renders them prematurely out of service. Effective and reliable sensing elements are thus in high demand to make prognosis on the mechanical properties and occurrence of damage to pavements. Therefore, in this paper, various types of functionality enhancement of industrialized optical fiber sensors for pavement monitoring are developed, with the corresponding operational principles clarified in theory and the performance double checked by basic experiments. Furthermore, a self-healing optical fiber sensing network system is adopted to accomplish full-scale monitoring of pavements. The application of optical fiber sensors assembly and self-healing network system in pavement has been carried out to validate the feasibility. It has been proved that the research in this article provides a valuable method and meaningful guidance for the integrity monitoring of civil structures, especially pavements. PMID:24854060

  10. DEVELOPMENT OF A HYDROPHOBIC SUBSTANCE TO MITIGATE PAVEMENT ICE ADHESION

    EPA Science Inventory

    The specific problem to which this report is addressed is the development of a hydrophobic substance to mitigate the adhesion of ice to pavement as an alternative to deicing chemicals. The factors involved in evaluating this concept are the following: Economics; safety; environme...

  11. Alternative aircraft loading index for pavement structural analysis

    SciTech Connect

    Loizos, A.; Charonitis, G.

    1999-05-01

    The most common practical way to simplify the structural analysis of airfield pavements is the use of equivalent single wheel load models instead of the actual gear of the aircrafts. As the accuracy and reliability of these models strongly affects the design and evaluation of airfield pavements, there is considerable need to investigate both system approaches. The first one, which uses a constant value for the pressure while the radius is variable, is currently under use by the aircraft classification number-pavement classification number method of the International Civil Aviation Organization, but despite this fact it proved to be inadequate to express the aircraft loading in many situations. On the contrary, according to this study, the second model, which has a constant value for the radius while the pressure varies, is more reliable, and it can be an interesting alternative. Thus, based on this model, an aircraft loading index is introduced, which aims to be a simple and reliable factor for expressing the severity of the loading of the aircrafts and a utility for several matters related to the airfield pavement applications.

  12. Monitoring Strategies in Permeable Pavement Systems to Optimize Maintenance Scheduling

    EPA Science Inventory

    As the surface in a permeable pavement system clogs and performance decreases, maintenance is required to preserve the design function. Currently, guidance is limited for scheduling maintenance on an as needed basis. Previous research has shown that surface clogging in a permea...

  13. Nitrogen Transformations in Three Types of Permeable Pavement

    EPA Science Inventory

    In 2009, USEPA constructed a 0.4-ha (1-ac) parking lot at the Edison Environmental Center in Edison, NJ, that incorporated three different permeable pavement types - permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). The driving lanes...

  14. Measuring Clogging with Pressure Transducers in Permeable Pavement Strips

    EPA Science Inventory

    Two issues that have a negative affect on the long term hydrologic performance of permeable pavement systems are surface clogging and clogging at the interface with the underlying soil. Surface clogging limits infiltration capacity and results in bypass if runoff rate exceeds in...

  15. Nutrient infiltrate concentrations from three permeable pavement types.

    PubMed

    Brown, Robert A; Borst, Michael

    2015-12-01

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable interlocking concrete pavement (PICP), pervious concrete (PC), and porous asphalt (PA). Each permeable pavement type has four, 54.9-m(2), lined sections that direct all infiltrate into 5.7-m(3) tanks enabling complete volume collection and sampling. This paper highlights the results from a 12-month period when samples were collected from 13 rainfall/runoff events and analyzed for nitrogen species, orthophosphate, and organic carbon. Differences in infiltrate concentrations among the three permeable pavement types were assessed and compared with concentrations in rainwater samples and impervious asphalt runoff samples, which were collected as controls. Contrary to expectations based on the literature, the PA infiltrate had significantly larger total nitrogen (TN) concentrations than runoff and infiltrate from the other two permeable pavement types, indicating that nitrogen leached from materials in the PA strata. There was no significant difference in TN concentration between runoff and infiltrate from either PICP or PC, but TN in runoff was significantly larger than in the rainwater, suggesting meaningful inter-event dry deposition. Similar to other permeable pavement studies, nitrate was the dominant nitrogen species in the infiltrate. The PA infiltrate had significantly larger nitrite and ammonia concentrations than PICP and PC, and this was presumably linked to unexpectedly high pH in the PA infiltrate that greatly exceeded the optimal pH range for nitrifying bacteria. Contrary to the nitrogen results, the PA infiltrate had significantly smaller orthophosphate concentrations than in rainwater, runoff, and infiltrate from PICP

  16. Predicting physical clogging of porous and permeable pavements

    NASA Astrophysics Data System (ADS)

    Yong, C. F.; McCarthy, D. T.; Deletic, A.

    2013-02-01

    SummaryPorous pavements are easily retrofitted, and effective in improving water quality and hydrology, but prone to clogging. Despite being a major determinant in the lifespan of porous pavements, there is limited information on the physical clogging processes through these systems. The aim of this study was to understand the main physical processes that govern physical clogging and develop a simple black-box model that predicts physical clogging. The key variables that were hypothesised to influence clogging were pavement design and climate characteristics. Two compressed time scale laboratory experiments were conducted over 3 years on three common porous pavement types; monolithic porous asphalt, modular Hydrapave and monolithic Permapave. Pavement design was found to be an important role in clogging. Permapave did not clog even after 26 years of operation in simulated sub-tropical Brisbane (Australia) climate while porous asphalt and Hydrapave clogged after just 12 years, from surface clogging and geotextile clogging, respectively. Each system was tested using two different dosing patterns: (1) continual wetting with no dry periods and (2) variable inflow rates with drying periods (i.e. representing more natural conditions). The latter dosing method approximately doubled the lifespan of all systems suggesting the influence of climate conditions on clogging. Clogging was found to be highly correlated with cumulative volume and flow rate. A simple black-box regression model that predicts physical clogging was developed as a function of cumulative volume and Brisbane climatic conditions. However it is very likely that the shape of this regression is general, and that it could be calibrated for different climates in the future.

  17. An assessment of the skid resistance effect on traffic safety under wet-pavement conditions.

    PubMed

    Pardillo Mayora, José M; Jurado Piña, Rafael

    2009-07-01

    Pavement-tire friction provides the grip that is required for maintaining vehicle control and for stopping in emergency situations. Statistically significant negative correlations of skid resistance values and wet-pavement accident rates have been found in previous research. Skid resistance measured with SCRIM and crash data from over 1750km of two-lane rural roads in the Spanish National Road System were analyzed to determine the influence of pavement conditions on safety and to assess the effects of improving pavement friction on safety. Both wet- and dry-pavement crash rates presented a decreasing trend as skid resistance values increased. Thresholds in SCRIM coefficient values associated with significant decreases in wet-pavement crash rates were determined. Pavement friction improvement schemes were found to yield significant reductions in wet-pavement crash rates averaging 68%. The results confirm the importance of maintaining adequate levels of pavement friction to safeguard traffic safety as well as the potential of pavement friction improvement schemes to achieve significant crash reductions. PMID:19540980

  18. A Research on the Association of Pavement Surface Damages Using Data Mining

    NASA Astrophysics Data System (ADS)

    Hung, Ching-Tsung; Chang, Jia-Ray; Chen, Jian-Da; Chou, Chien-Cheng; Chen, Shih-Huang

    The association of pavement surface damages used to rely on the judgments of the experts. However, with the accumulation of data in the pavement surface maintenance database and the improvement of Data Mining, there are more and more methods available to explore the association of pavement surface damages. This research adopts Apriori algorithm to conduct association analysis on pavement surface damages. From the experience of experts, it has been believed that the association of road damages is complicated. However, through case studies, it has been found that pavement surface damages are caused among longitudinal cracking, alligator cracking and pen-holes, and they are unidirectional influence. In addition, with the help of association rules, it has been learned that, in pavement surface preventative maintenance, the top priority should be the repair of longitudinal cracking and alligator cracking, which can greatly reduce the occurrence of pen-holes and the risk of state compensations.

  19. Recycled materials in asphalt pavements, January 1980-June 1991 (citations from the NTIS database). Rept. for Jan 80-Jun 91

    SciTech Connect

    Not Available

    1991-06-01

    The bibliography contains citations concerning the recycling of asphalt pavement materials, and the use of other recycled materials to manufacture asphalt pavement. Articles discuss methods used for recycling bituminous pavement including hot-mix and cold-mix. Materials used to improve recycled pavement, and recycled materials used in asphalt pavement include latexes, rubber scrap such as tires, glass shards, concretes, dusts, waste oils, roofing wastes, sulfur, and metal refining sludges. Testing and evaluation of recycled pavements both in laboratories and in test cases are considered. (The bibliography contains 75 citations.) (Also includes title list and subject index.)

  20. Experimental studies of the dilution of vehicle exhaust pollutants by environment-protecting pervious pavement.

    PubMed

    Liu, Chung-Ming; Chen, Jui-Wen; Tsai, Jen-Hui; Lin, Wei-Shian; Yen, M-T; Chen, Ting-Hao

    2012-01-01

    This study determines whether environment-protecting pervious pavement can dilute pollutants immediately after emissions from vehicle. The turbulence-driven dry-deposition process is too slow to be considered in this aspect. The pavement used is the JW pavement (according to its inventors name), a high-load-bearing water-permeable pavement with patents in over 100 countries, which has already been used for more than 8 years in Taiwan and is well suited to replacing conventional road pavement, making the potential implementation of the study results feasible. The design of this study included two sets of experiments. Variation of the air pollutant concentrations within a fenced area over the JW pavement with one vehicle discharging emissions into was monitored and compared with results over a non-JW pavement. The ambient wind speed was low during the first experiment, and the results obtained were highly credible. It was found that the JW pavement diluted vehicle pollutant emissions near the ground surface by 40%-87% within 5 min of emission; whereas the data at 2 m height suggested that about 58%-97% of pollutants were trapped underneath the pavement 20 min after emission. Those quantitative estimations may be off by +/- 10%, if errors in emissions and measurements were considered. SO2 and CO2 underwent the most significant reduction. Very likely, pollutants were forced to move underneath due to the special design of the pavement. During the second experiment, ambient wind speeds were high and the results obtained had less credibility, but they did not disprove the pollutant dilution capacity of the JW pavement. In order to track the fate of pollutants, parts of the pavement were removed to reveal a micro version of wetland underneath, which could possibly hold the responsibility of absorbing and decomposing pollutants to forms harmless to the environment and human health. PMID:22393814

  1. Fatigue behavior of rubber modified pavements. Final report, 1994-1996

    SciTech Connect

    Raad, L.; Saboundjian, S.

    1997-05-01

    Over the last 15 years, a number of rubberized pavement projects have been built in Alaska. Initial laboratory and field investigations sponsored by the Alaska Department of Transportation and Public Facilities (AKDOT&PF) and conducted by Raad et al. (1995) indicated improved fatigue performance of the rubberized sections in comparison with conventional asphalt concrete pavements. The report presents the results of a follow-up investigation to develop design equations for rubberized pavements in Alaska.

  2. Evaluation of flexible pavement crack sealing methods used in Utah

    NASA Astrophysics Data System (ADS)

    Belangie, M. C.; Anderson, D. I.

    1981-01-01

    Criteria to improve the effectiveness of Utah's flexible pavements crack sealing practice were studied. Field measurements, in-depth interviews questionaires were used. Findings indicate that flexible pavement cracking is a significant problem in the Far West, Rocky Mountains, Great Lakes and New England. Choice of materials is effected by storage requirements and equipment available. Prepackaging of materials designed for crack sealing has resulted in improvements in control of mix and material properties. Low temperature and freeze thaw cycles significantly effect the amount of thermal cracking and the performance of crack sealant. Ductile sealants, such as Crumb rubber/asphalt cement mixes, in combination with routing appear to offer substantial gains in sealant life and performance.

  3. AN OPTIMAL MAINTENANCE MANAGEMENT MODEL FOR AIRPORT CONCRETE PAVEMENT

    NASA Astrophysics Data System (ADS)

    Shimomura, Taizo; Fujimori, Yuji; Kaito, Kiyoyuki; Obama, Kengo; Kobayashi, Kiyoshi

    In this paper, an optimal management model is formulated for the performance-based rehabilitation/maintenance contract for airport concrete pavement, whereby two types of life cycle cost risks, i.e., ground consolidation risk and concrete depreciation risk, are explicitly considered. The non-homogenous Markov chain model is formulated to represent the deterioration processes of concrete pavement which are conditional upon the ground consolidation processes. The optimal non-homogenous Markov decision model with multiple types of risk is presented to design the optimal rehabilitation/maintenance plans. And the methodology to revise the optimal rehabilitation/maintenance plans based upon the monitoring data by the Bayesian up-to-dating rules. The validity of the methodology presented in this paper is examined based upon the case studies carried out for the H airport.

  4. Development of a fiber optic pavement subgrade strain measurement system

    NASA Astrophysics Data System (ADS)

    Miller, Craig Emerson

    2000-11-01

    This dissertation describes the development of a fiber optic sensing system to measure strains within the soil subgrade of highway pavements resulting from traffic loads. The motivation to develop such a device include improvements to: (1)all phases of pavement design, (2)theoretical models used to predict pavement performance, and (3)pavement rehabilitation. The design of the sensing system encompasses selecting an appropriate transducer design as well as the development of optimal optical and demodulation systems. The first is spring based, which attempts to match its spring stiffness to that of the soil-data indicate it is not an optimal transducer design. The second transducer implements anchoring plates attached to two telescoping tubes which allows the soil to be compacted to a desired density between the plates to dictate the transducer's behavior. Both transducers include an extrinsic Fabry- Perot cavity to impose the soil strains onto a phase change of the optical signal propagating through the cavity. The optical system includes a low coherence source and allows phase modulation via path length stretching by adding a second interferometer in series with the transducer, resulting in a path matched differential interferometer. A digitally implemented synthetic heterodyne demodulator based on a four step phase stepping algorithm is used to obtain unambiguous soil strain information from the displacement of the Fabry-Perot cavity. The demodulator is calibrated and characterized by illuminating the transducer with a second long coherence source of different wavelength. The transducer using anchoring plates is embedded within cylindrical soil specimens of varying soil types and soil moisture contents. Loads are applied to the specimen and resulting strains are measured using the embedded fiber optic gage and LVDTs attached to the surface of the specimen. This experimental verification is substantiated using a finite element analysis to predict any differences

  5. Experimental AC (Asphalt Concrete) overlays of PCC pavement

    NASA Astrophysics Data System (ADS)

    Smith, R. D.

    1983-11-01

    A series of experimental asphalt concrete (AC) overlays was constructed over an existing distressed portland cement concrete pavement on Interstate 80 near Boca, California. The experimental overlays included rubberized dense-graded AC, rubberized open-graded AC, a rubber flush coat interlayer, dense-graded AC with short polyester fibers and Bituthene interlayer strips. The report presents a description and discussion of AC mix batching, construction observations, laboratory testing, overlay covering, and initial performance evaluation.

  6. Use of scrap rubber in asphalt pavement surfaces

    NASA Astrophysics Data System (ADS)

    Eaton, Robert A.; Roberts, Richard J.; Blackburn, Robert R.

    1991-12-01

    Scrap tire rubber was mixed into an asphalt concrete wearing course to study the effect of ice disbonding from the pavement surface under traffic. Rubber contents of 0, 3, 6, and 12 percent by weight were studied. Initial laboratory ice disbonding test results led to the development of a new paving material, Chunk Rubber Asphalt Concrete (CRAC), that uses larger pieces of rubber in a much denser asphalt concrete mix. Strength values doubled and ice disbonding performance was enhanced.

  7. Kinect, a Novel Cutting Edge Tool in Pavement Data Collection

    NASA Astrophysics Data System (ADS)

    Mahmoudzadeh, A.; Firoozi Yeganeh, S.; Golroo, A.

    2015-12-01

    Pavement roughness and surface distress detection is of interest of decision makers due to vehicle safety, user satisfaction, and cost saving. Data collection, as a core of pavement management systems, is required for these detections. There are two major types of data collection: traditional/manual data collection and automated/semi-automated data collection. This paper study different non-destructive tools in detecting cracks and potholes. For this purpose, automated data collection tools, which have been utilized recently are discussed and their applications are criticized. The main issue is the significant amount of money as a capital investment needed to buy the vehicle. The main scope of this paper is to study the approach and related tools that not only are cost-effective but also precise and accurate. The new sensor called Kinect has all of these specifications. It can capture both RGB images and depth which are of significant use in measuring cracks and potholes. This sensor is able to take image of surfaces with adequate resolution to detect cracks along with measurement of distance between sensor and obstacles in front of it which results in depth of defects. This technology has been very recently studied by few researchers in different fields of studies such as project management, biomedical engineering, etc. Pavement management has not paid enough attention to use of Kinect in monitoring and detecting distresses. This paper is aimed at providing a thorough literature review on usage of Kinect in pavement management and finally proposing the best approach which is cost-effective and precise.

  8. Statistical methods for pavement performance curve building, historical analysis, data sampling and storage. Final report, May 1997--July 1998

    SciTech Connect

    Zimmerman, K.A.; Bahulkar, A.M.

    1998-08-01

    The use of a pavement management system provides a state highway agency with the tools necessary to conduct a multi-year analysis of the maintenance and rehabilitation needs within the state based on both current needs and expected future conditions. In order to adequately predict future conditions, pavement performance models must be developed to reflect the deterioration trends of the agency`s pavements. At the time the SDDOT pavement management system was implemented in 1994, the Department developed a new condition rating system to evaluate the existing conditions of the state maintained pavements. At the same time, expert-based pavement performance models were developed to approximate the deterioration patterns of the highways based on pavement families (groupings of pavements with similar characteristics). A recommendation from that study (SD93-14) was to update the curves based on historical performance once sufficient data had been collected.

  9. Investigation of mechanical properties of pavement through electromagnetic techniques

    NASA Astrophysics Data System (ADS)

    Benedetto, Andrea; Tosti, Fabio; D'Amico, Fabrizio

    2014-05-01

    Ground-penetrating radar (GPR) is considered as one of the most flexible geophysical tools that can be effectively and efficiently used in many different applications. In the field of pavement engineering, GPR can cover a wide range of uses, spanning from physical to geometrical inspections of pavements. Traditionally, such inferred information are integrated with mechanical measurements from other traditional (e.g. plate bearing test) or non-destructive (e.g. falling weight deflectometer) techniques, thereby resulting, respectively, in time-consuming and low-significant measurements, or in a high use of technological resources. In this regard, the new challenge of retrieving mechanical properties of road pavements and materials from electromagnetic measurements could represent a further step towards a greater saving of economic resources. As far as concerns unpaved and bound layers it is well-known that strength and deformation properties are mostly affected, respectively, by inter-particle friction and cohesion of soil particles and aggregates, and by bitumen adhesion, whose variability is expressed by the Young modulus of elasticity. In that respect, by assuming a relationship between electromagnetic response (e.g. signal amplitudes) and bulk density of materials, a reasonable correlation between mechanical and electric properties of substructure is therefore expected. In such framework, a pulse GPR system with ground-coupled antennae, 600 MHz and 1600 MHz centre frequencies was used over a 4-m×30-m test site composed by a flexible pavement structure. The horizontal sampling resolution amounted to 2.4×10-2 m. A square regular grid mesh of 836 nodes with a 0.40-m spacing between the GPR acquisition tracks was surveyed. Accordingly, a light falling weight deflectometer (LFWD) was used for measuring the elastic modulus of pavement at each node. The setup of such instrument consisted of a 10-kg falling mass and a 100-mm loading plate so that the influence domain

  10. GPR used in combination with other NDT methods for assessing pavements in PPP projects

    NASA Astrophysics Data System (ADS)

    Loizos, Andreas; Plati, Christina

    2014-05-01

    In the recent decades, Public-Private Partnerships (PPP) has been adopted for highway infrastructure procurement in many countries. PPP projects typically take the form of a section of highway and connecting roadways which are to be construction and managed for a given concession period. Over the course of the highway concession period, the private agency takes over the pavement maintenance and rehabilitation duties. On this purpose, it is critical to find the most cost effective way to maintain the infrastructure in compliance with the agreed upon performance measures and a Pavement Management Systems (PMS) is critical to the success of this process. For the prosperous operation of a PMS it is necessary to have appropriate procedures for pavement monitoring and evaluation, which is important in many areas of pavement engineering. Non Destructive Testing (NDT) has played a major role in pavement condition monitoring, assessments and evaluation accomplishing continuous and quick collection of pavement data. The analysis of this data can lead to indicators related to trigger values (criteria) that define the pavement condition based on which the pavement "health" is perceived helping decide whether there is the need or not to intervene in the pavement. The accomplished perception appoints required management activities for preserving pavements in favor not only of the involved highway/road agencies but also of users' service. Amongst NDT methods Ground Penetrating Radar (GPR) seems to be a very powerful toll, as it provides a range of condition and construction pavement information. It can support effectively the implementation of PMS activities in the framework of pavement monitoring and evaluation. Given that, the present work aims to the development and adaptation of a protocol for the use of GPR in combination with other NDT methods, such as Falling Weight Deflectometer (FWD), for assessing pavements in PPP projects. It is based on the experience of Laboratory of

  11. GPR in Nondestructive Quality Assurance of New Asphalt Pavements

    NASA Astrophysics Data System (ADS)

    Poikajärvi, J.; Peisa, K.; Narbro, A.

    2012-04-01

    Mara Nord is an international cooperation project financed by Interreg IVA Nord funding program with partners from Finland, Sweden and Norway. One of the objectives in Mara Nord project has been to research the quality assurance of new asphalt pavement. Ground penetrating radar (GPR) survey is used as an alternative method for coring in quality assurance. There exist numerous advantages for the use of GPR. For example, the fluent measuring arrangements without closing the traffic on the road and the extensive continuous profile that can be constructed from the measuring data. Within the framework of Mara Nord Project field tests were organized in Seinäjoki region in Finland on August 2011. The tests were done by four consulting companies from Finland and Rovaniemi University of Applied Sciences. The aim of these tests was to compare the measured dielectric value profiles and the calculated void content profiles of the equipment. The tested equipment was GSSI manufactured SIR-20 and 1 GHz horn antennas. Void content values were calculated using the model presented by Mr. Roimela (1997). All core samples were taken from the right wheel path. The same reference core samples were used when analyzing the data of each GPR equipment. Some samples were taken right after the pavement work was completed with the rest three weeks after during the test measurements. The tests indicated that GPRs have very good repeatability in measuring dielectric changes on top surface layers of asphalt pavements. Furthermore, different GPRs locate the same detectable longitudinal dielectric changes with high accuracy. Some differences were found in the dielectric value levels, yet reproducibility of the calculated void content values was quite good. The test data was also used to evaluate the reliability of the regression model between the dielectric values measured through GPR and the void content of the pavement determined from reference cores. Test data indicated that accurate regression

  12. Statistical methods for pavement performance curve building, historical analysis, data sampling and storage: Appendix D. Final report

    SciTech Connect

    1998-08-01

    The technical memorandum is intended to discuss the detailed procedure required for carrying out the statistical analyses of historical pavement condition data for building pavement performance curves. This chapter assumes the availability of the historical data in a spreadsheet format (Microsoft{trademark} Excel) that has been retrieved from the master (pavement management system) database.

  13. Asphalt Pavement Aging and Temperature Dependent Properties Using Functionally Graded Viscoelastic Model

    ERIC Educational Resources Information Center

    Dave, Eshan V.

    2009-01-01

    Asphalt concrete pavements are inherently graded viscoelastic structures. Oxidative aging of asphalt binder and temperature cycling due to climatic conditions being the major cause of non-homogeneity. Current pavement analysis and simulation procedures dwell on the use of layered approach to account for these non-homogeneities. The conventional…

  14. 78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... data from three pavement types: dense-graded asphaltic concrete (DGAC), open-graded asphaltic concrete (OGAC), and Portland cement concrete (PCC). Prediction of future noise levels is based on the ``average... to consider a wider range of asphaltic concrete and PCC pavements within the agency's traffic...

  15. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - Abstract

    EPA Science Inventory

    The EPA’s Urban Watershed Management Branch (UWMB) is monitoring an instrumented, working, 110-space pervious pavement parking at EPA’s Edison Environmental Center (EEC). Permeable pavement systems are classified as stormwater best management practices (BMPs) which reduce runo...

  16. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - presentation

    EPA Science Inventory

    The EPA’s Urban Watershed Management Branch has been monitoring an instrumented 110-space pervious pavement parking lot. The lot is used by EPA personnel and visitors to the Edison Environmental Center. The design includes 28-space rows of three permeable pavement types: asphal...

  17. Permeable pavement monitoring at the EPA's Edison Environmental Center demonstration site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  18. Effects of reclaimed asphalt pavement on indirect tensile strength test of conditioned foamed asphalt mix

    NASA Astrophysics Data System (ADS)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    This paper presents the results of Indirect Tensile Strength (ITS) Test for samples prepared with reclaimed asphalt pavement (RAP). Samples were conditioned in water at 25°C for 24 hours prior to testing. Results show that recycled aggregate from reclaimed asphalt pavement performs as well as virgin aggregate.

  19. The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditio...

  20. Evaluation of Surface and Subsurface Processes in Permeable Pavement Infiltration Trenches

    EPA Science Inventory

    The hydrologic performance of permeable pavement systems can be affected by clogging of the pavement surface and/or clogging at the interface where the subsurface storage layer meets the underlying soil. As infiltration and exfiltration are the primary functional mechanisms for ...

  1. Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System

    EPA Science Inventory

    The U.S. Environmental Protection Agency constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable pavement in the parking lanes which were designed to receive run-on from the impervious hot-mix asphalt driving lanes. Twelve lined permeable pavement sec...

  2. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Federal lands pavement management system (PMS). 970.208... HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems § 970.208 Federal lands pavement management system (PMS). In addition to the requirements provided in § 970.204,...

  3. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Indian lands pavement management system (PMS). 973.208... HIGHWAYS MANAGEMENT SYSTEMS PERTAINING TO THE BUREAU OF INDIAN AFFAIRS AND THE INDIAN RESERVATION ROADS PROGRAM Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system...

  4. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Federal lands pavement management system (PMS). 971.208... HIGHWAYS FOREST SERVICE MANAGEMENT SYSTEMS Forest Highway Program Management Systems § 971.208 Federal lands pavement management system (PMS). In addition to the requirements provided in § 971.204, the...

  5. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... include: (i) A pavement condition analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance analysis that includes present and predicted performance and...

  6. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance analysis that includes present and predicted performance and an estimate of the remaining...

  7. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... include: (i) A pavement condition analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance analysis that includes present and predicted performance and...

  8. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... 23 Highways 1 2011-04-01 2011-04-01 false Federal lands pavement management system (PMS). 971.208... lands pavement management system (PMS). In addition to the requirements provided in § 971.204, the...

  9. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... 23 Highways 1 2011-04-01 2011-04-01 false Indian lands pavement management system (PMS). 973.208... PROGRAM Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system...

  10. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Federal lands pavement management system (PMS). 970.208 Section 970.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL LANDS HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems § 970.208 Federal lands pavement management system...

  11. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Federal lands pavement management system (PMS). 971.208 Section 971.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL LANDS HIGHWAYS FOREST SERVICE MANAGEMENT SYSTEMS Forest Highway Program Management Systems § 971.208 Federal lands pavement management system (PMS)....

  12. Assessment of porous asphalt pavement performance: hydraulics and water quality

    NASA Astrophysics Data System (ADS)

    Briggs, J. F.; Ballestero, T. P.; Roseen, R. M.; Houle, J. J.

    2005-05-01

    The objective of this study is to focus on the water quality treatment and hydraulic performance of a porous asphalt pavement parking lot in Durham, New Hampshire. The site was constructed in October 2004 to assess the suitability of porous asphalt pavement for stormwater management in cold climates. The facility consists of a 4-inch asphalt open-graded friction course layer overlying a high porosity sand and gravel base. This base serves as a storage reservoir in-between storms that can slowly infiltrate groundwater. Details on the design, construction, and cost of the facility will be presented. The porous asphalt pavements is qualitatively monitored for signs of distress, especially those due to cold climate stresses like plowing, sanding, salting, and freeze-thaw cycles. Life cycle predictions are discussed. Surface infiltration rates are measured with a constant head device built specifically to test high infiltration capacity pavements. The test measures infiltration rates in a single 4-inch diameter column temporarily sealed to the pavement at its base. A surface inundation test, as described by Bean, is also conducted as a basis for comparison of results (Bean, 2004). These tests assess infiltration rates soon after installation, throughout the winter, during snowmelt, after a winter of salting, sanding, and plowing, and after vacuuming in the spring. Frost penetration into the subsurface reservoir is monitored with a frost gauge. Hydrologic effects of the system are evaluated. Water levels are monitored in the facility and in surrounding wells with continuously logging pressure transducers. The 6-inch underdrain pipe that conveys excess water in the subsurface reservoir to a riprap pad is also continuously monitored for flow. Since porous asphalt pavement systems infiltrate surface water into the subsurface, it is important to assess whether water quality treatment performance in the subsurface reservoir is adequate. The assumed influent water quality is

  13. Use of Ground Penetrating Radar at the FAA's National Airport Pavement Test Facility

    NASA Astrophysics Data System (ADS)

    Injun, Song

    2015-04-01

    The Federal Aviation Administration (FAA) in the United States has used a ground-coupled Ground Penetrating Radar (GPR) at the National Airport Pavement Test Facility (NAPTF) since 2005. One of the primary objectives of the testing at the facility is to provide full-scale pavement response and failure information for use in airplane landing gear design and configuration studies. During the traffic testing at the facility, a GSSI GPR system was used to develop new procedures for monitoring Hot Mix Asphalt (HMA) pavement density changes that is directly related to pavement failure. After reviewing current setups for data acquisition software and procedures for identifying different pavement layers, dielectric constant and pavement thickness were selected as dominant parameters controlling HMA properties provided by GPR. A new methodology showing HMA density changes in terms of dielectric constant variations, called dielectric sweep test, was developed and applied in full-scale pavement test. The dielectric constant changes were successfully monitored with increasing airplane traffic numbers. The changes were compared to pavement performance data (permanent deformation). The measured dielectric constants based on the known HMA thicknesses were also compared with computed dielectric constants using an equation from ASTM D4748-98 Standard Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radar. Six inches diameter cylindrical cores were taken after construction and traffic testing for the HMA layer bulk specific gravity. The measured bulk specific gravity was also compared to monitor HMA density changes caused by aircraft traffic conditions. Additionally this presentation will review the applications of the FAA's ground-coupled GPR on embedded rebar identification in concrete pavement, sewer pipes in soil, and gage identifications in 3D plots.

  14. Synthesis report: D-cracking in portland cement concrete pavements

    NASA Astrophysics Data System (ADS)

    Thompson, S. R.; Olsen, M. P. J.; Dempsey, B. J.

    1980-06-01

    The mechanisms and testing procedures for D-cracking in portland cement concrete pavements are examined. Benefication procedures are also investigated. The three general responses to freezing in the aggregate/paste system include elastic accommodation, high internal pressure, and high external pressure. It is found that the critical aggregate parameters influencing D-cracking are degree of saturation, maximum particle size, permeability, porosity, and pore size distribution. Evaluation of present laboratory testing procedures indicated that the ASTM C666, VPI slow-cool, Mercury Porosimetry, and Iowa Pore Index Tests correlated the best with field performance of concrete with respect to D-cracking.

  15. Numerical modeling of inelastic structures at loading of steady state rolling. Thermo-mechanical asphalt pavement computation

    NASA Astrophysics Data System (ADS)

    Wollny, Ines; Hartung, Felix; Kaliske, Michael

    2016-05-01

    In order to gain a deeper knowledge of the interactions in the coupled tire-pavement-system, e.g. for the future design of durable pavement structures, the paper presents recent results of research in the field of theoretical-numerical asphalt pavement modeling at material and structural level, whereby the focus is on a realistic and numerically efficient computation of pavements under rolling tire load by using the finite element method based on an Arbitrary Lagrangian Eulerian (ALE) formulation. Inelastic material descriptions are included into the ALE frame efficiently by a recently developed unsplit history update procedure. New is also the implementation of a viscoelastic cohesive zone model into the ALE pavement formulation to describe the interaction of the single pavement layers. The viscoelastic cohesive zone model is further extended to account for the normal pressure dependent shear behavior of the bonding layer. Another novelty is that thermo-mechanical effects are taken into account by a coupling of the mechanical ALE pavement computation to a transient thermal computation of the pavement cross-section to obtain the varying temperature distributions of the pavement due to climatic impact. Then, each ALE pavement simulation considers the temperature dependent asphalt material model that includes elastic, viscous and plastic behavior at finite strains and the temperature dependent viscoelastic cohesive zone formulation. The temperature dependent material parameters of the asphalt layers and the interfacial layers are fitted to experimental data. Results of coupled tire-pavement computations are presented to demonstrate potential fields of application.

  16. Permeable pavement and stormwater management systems: a review.

    PubMed

    Imran, H M; Akib, Shatirah; Karim, Mohamed Rehan

    2013-01-01

    Uncontrolled stormwater runoff not only creates drainage problems and flash floods but also presents a considerable threat to water quality and the environment. These problems can, to a large extent, be reduced by a type of stormwater management approach employing permeable pavement systems (PPS) in urban, industrial and commercial areas, where frequent problems are caused by intense undrained stormwater. PPS could be an efficient solution for sustainable drainage systems, and control water security as well as renewable energy in certain cases. Considerable research has been conducted on the function of PPS and their improvement to ensure sustainable drainage systems and water quality. This paper presents a review of the use of permeable pavement for different purposes. The paper focuses on drainage systems and stormwater runoff quality from roads, driveways, rooftops and parking lots. PPS are very effective for stormwater management and water reuse. Moreover, geotextiles provide additional facilities to reduce the pollutants from infiltrate runoff into the ground, creating a suitable environment for the biodegradation process. Furthermore, recently, ground source heat pumps and PPS have been found to be an excellent combination for sustainable renewable energy. In addition, this study has identified several gaps in the present state of knowledge on PPS and indicates some research needs for future consideration. PMID:24527626

  17. An Overview Of Pavement Management System For Industrial Areas

    NASA Astrophysics Data System (ADS)

    Hokam, Vivek S.

    2012-03-01

    ACT With the current surge in national economy the industrial traffic has increased many folds in terms of quantity of load and traffic volume. This results in early deterioration of the roads. Also the serviceability reduces hampering the industry's supply of raw material and transport of finished goods. An efficient road transportation system is of vitally important for smooth operations of industrial units. Construction of new roads needs an enormous investment. However, once constructed the road network system requires huge resources to maintain serviceability and to ensure safe passage at an appropriate speed and with low VOC (Vehicle Operating Cost). Road maintenance is therefore an essential function and should be carried out on a timely basis. The cost of providing and maintaining the roads for the industrial areas at an acceptable serviceability level is quite high. It is therefore essential for a transportation engineer to attempt establishing an acceptable pavement condition level from economic, safety and environmental point of view. In today's economic environment of constrained budgets, as the existing road infrastructure has aged, a more systematic approach towards determining maintenance and rehabilitation needs is necessary. The efficient pavement management system shall provide objective information and useful analysis to ensure consistent and cost effective decisions related to preservation of existing industrial road network in healthy condition.

  18. Using ground-penetrating radar for assessing highway pavement thickness

    NASA Astrophysics Data System (ADS)

    Lenngren, Carl A.; Bergstrom, Joergen; Ersson, Benny M.

    2000-07-01

    Surface distress is a fairly good indicator of rehabilitation needs but it does not directly relate to remaining life estimates. Mechanistic pavement design requires that strains be calculated utilizing more or less complex modeling. Over the years many devices measuring surface deflections under a given load have been developed. The device by choice for assessing strains due to load is the falling weight deflectometer (FWD). It creates an impulse load on the pavement surface. The data are commonly used in models for backcalculation of elastic moduli and strains. More complex modeling would involve finite element or dynamic element methods. The FWD method has proven to be an excellent tool for overlay design. For this purpose its simplicity and straightforwardness are well documented. However, to successfully backcalculate layer stiffness adequate layer thickness is needed. Thus there is a strong need for assessing layer data at testing points. Using Ground Penetrating Radar (GPR) it is possible to achieve data without coring. The present paper is a part of an ongoing bearing capacity study carried out by a regional road administration in central Sweden. Its objective is to optimize testing for equipment and methods used and presently available. In addition to evaluate the results from the study, the present paper discusses some other applications for GPR that may evolve from it.

  19. Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China.

    PubMed

    Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

    2016-03-01

    In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase. PMID:27011196

  20. Thickness and air voids measurement on asphalt concrete pavements using ground-penetrating radar

    NASA Astrophysics Data System (ADS)

    Dhakal, Sharad Raj

    Layer thickness and air voids are important parameters in quality assurance of newly paved hot mix asphalt (HMA) pavements. A non-destructive testing (NDT) technique was used to collect layer thickness information. The thicknesses estimated by the technique were compared with core thicknesses. Ground penetrating radar (GPR) system with air coupled antennas was used for on-site pavement data collection. Two application softwares - RADAN and ROAD DOCTOR - were used to process the field data for estimating layer thicknesses and air voids along the scanned pavements. 150 mm diameter cores taken from random locations on the pavements were tested in the laboratory to determine layer thickness and air voids. Statistical analyses were conducted to compare thicknesses and generate a regression equation relating air voids and dielectric constant of the pavement material. No significant differences were found between thickness estimates from RADAN and ROAD DOCTOR softwares when compared to the core measurements. However, RADAN and ROAD DOCTOR results are marginally significantly different from each other. ROAD DOCTOR software was used to generate air voids for the pavements scanned. Laboratory results from cores were utilized to determine calibration factors for the air voids -- dielectric equation. A relationship between air voids and dielectric constant is presented. It is concluded that GPR system with air coupled antennas used alongside a reduced core testing has a potential for quality control of newly paved hot mixed asphalt pavements.

  1. Decision model in the laser scanning system for pavement crack detection

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoming; Huang, Jianping; Liu, Wanyu

    2011-12-01

    Pavement crack detection plays an important role in the pavement maintaining and management. Recently, the laser scanning technique for pavement crack detection becomes more and more popular due to its ability of discriminating dark areas, which are not caused by pavement distress such as tire marks, oil spills, and shadows. However, this technique still bears some errors for pavement crack recognition errors, thus in the present work, the factors contributed to these errors in laser scanning system are first analyzed, and then a decision model for the laser scanning pavement crack detection system based on the hypothesis test is proposed. Experimental analyses and results show that this model not only allows us to build the relationship between the contribution factors and crack detection accuracy and to provide the criteria to compare the detection accuracy for the different roads, but also can be used to judge whether the crack exists with a reasonable number of deformed light stripes. Therefore, the proposed decision model can provide guidance on the pavement crack detection and has a practical value.

  2. Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China

    PubMed Central

    Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

    2016-01-01

    In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase. PMID:27011196

  3. Evaluation Model for Pavement Surface Distress on 3d Point Clouds from Mobile Mapping System

    NASA Astrophysics Data System (ADS)

    Aoki, K.; Yamamoto, K.; Shimamura, H.

    2012-07-01

    This paper proposes a methodology to evaluate the pavement surface distress for maintenance planning of road pavement using 3D point clouds from Mobile Mapping System (MMS). The issue on maintenance planning of road pavement requires scheduled rehabilitation activities for damaged pavement sections to keep high level of services. The importance of this performance-based infrastructure asset management on actual inspection data is globally recognized. Inspection methodology of road pavement surface, a semi-automatic measurement system utilizing inspection vehicles for measuring surface deterioration indexes, such as cracking, rutting and IRI, have already been introduced and capable of continuously archiving the pavement performance data. However, any scheduled inspection using automatic measurement vehicle needs much cost according to the instruments' specification or inspection interval. Therefore, implementation of road maintenance work, especially for the local government, is difficult considering costeffectiveness. Based on this background, in this research, the methodologies for a simplified evaluation for pavement surface and assessment of damaged pavement section are proposed using 3D point clouds data to build urban 3D modelling. The simplified evaluation results of road surface were able to provide useful information for road administrator to find out the pavement section for a detailed examination and for an immediate repair work. In particular, the regularity of enumeration of 3D point clouds was evaluated using Chow-test and F-test model by extracting the section where the structural change of a coordinate value was remarkably achieved. Finally, the validity of the current methodology was investigated by conducting a case study dealing with the actual inspection data of the local roads.

  4. Pavement-management system for concrete roadways in Virginia. Phase 1. Condition ratings. Final report

    SciTech Connect

    Long, R.R.

    1988-04-01

    The report traces the development of a rating system for evaluating the service condition of Virginia's portland-cement concrete pavements. The service condition is assessed in terms of distress roughness, i.e., that portion of a pavement's poor-ride characteristics directly attributable to the occurrence of certain key distress types. Field surveys of the occurrence of these distresses provide the necessary data for estimating distress roughness through the use of prediction equations that have been established from the standard statistical analysis of pavement-section distress data and roughness measurements. Distress measurements and their corresponding ratings and a condition survey rating procedure are appended.

  5. Preliminary evaluation of the lifecycle costs and market barriers of reflective pavements

    SciTech Connect

    Ting, M.; Koomey, J.G.; Pomerantz, M.

    2001-11-21

    The objective of this study is to evaluate the life cycle costs and market barriers associated with using reflective paving materials in streets and parking lots as a way to reduce the urban heat island effect. We calculated and compared the life cycle costs of conventional asphalt concrete (AC) pavements to those of other existing pavement technologies with higher reflectivity-portland cement concrete (PCC), porous pavements, resin pavements, AC pavements using light-colored chip seals, and AC pavements using light-colored asphalt emulsion additives. We found that for streets and parking lots, PCC can provide a cost-effective alternative to conventional AC when severely damaged pavements must be completely reconstructed. We also found that rehabilitating damaged AC streets and intersections with thin overlays of PCC (ultra-thin white topping) can often provide a cost-effective alternative to standard rehabilitation techniques using conventional AC. Chip sealing is a common maintenance treatment for low-volume streets which, when applied using light-colored chips, could provide a reflective pavement surface. If the incremental cost of using light-colored chips is low, this chip sealing method could also be cost-effective, but the incremental costs of light-colored chips are as of yet uncertain and expected to vary. Porous pavements were found to have higher life cycle costs than conventional AC in parking lots, but several cost-saving features of porous pavements fell outside the boundaries of this study. Resin pavements were found to be only slightly more expensive than conventional AC, but the uncertainties in the cost and performance data were large. The use of light-colored additives in asphalt emulsion seal coats for parking lot pavements was found to be significantly more expensive than conventional AC, reflecting its current niche market of decorative applications. We also proposed two additional approaches to increasing the reflectivity of conventional AC

  6. Relating tensile, bending, and shear test data of asphalt binders to pavement performance

    SciTech Connect

    Chen, J.S.; Tsai, C.J.

    1998-12-01

    Eight different asphalt binders representing a wide range of applications for pavement construction were tested in uniaxial tension, bending, and shear stresses. Theoretical analyses were performed in this study to covert the data from the three engineering tests to stiffness moduli for predicting pavement performance. At low temperatures, high asphalt stiffness may induce pavement thermal cracking; thus, the allowable maximum stiffness was set at 1,000 MPa. At high temperatures, low asphalt stiffness may lead to pavement rutting (ruts in the road); master curves were constructed to rank the potential for rutting in the asphalts. All three viscoelastic functions were shown to be interchangeable within the linear viscoelastic region. When subjected to large deformation in the direct tension test, asphalt binders behaved nonlinear viscoelastic in which the data under bending, shear and tension modes were not comparable. The asphalts were, however, found toe exhibit linear viscoelasticity up to the failure point in the steady-state strain region.

  7. PHYSIOLOGICAL INFORMATION FOR PAVEMENT HEALTH MONITORING BASED ON SURFACE RIDE QUALITY

    NASA Astrophysics Data System (ADS)

    Tomiyama, Kazuya; Kawamura, Akira; Takahashi, Kiyoshi; Ishida, Tateki

    Pavement ride quality testing has traditionally been based on subjective questionnaire ratings. The questionnaire survey has ability to directly measure the sense of road users' ride quality. However, it is difficult to quantify the evaluation results based on the questionnaire due to its lack of objectivity. This study examines pavement health monitoring method using physiological information such as heart rate variability (HRV) for detecting mental stress of road users toward pavement ride quality. First, a results of a driving simulator experiment shows that potential mental stress caused by road roughness can be observed in high-frequency oscillations in 0.15-0.4Hz of HRV processed by continuous wavelet transform. Then, the high-frequency oscillations of HRV is summarized as an index related to the mental stress that makes objective ride quality evaluation possible. Finally, this study indicates that the index contributes to improve the accuracy of pavement health monitoring based on surface ride quality.

  8. Techniques to Determine Maintenace Frequency of Permeable Pavement Systems with Time Domain Reflectometers (TDRs

    EPA Science Inventory

    As the surface clogs in permeable pavement systems, they lose effectiveness and require maintenance. There is limited direct guidance for determining when maintenance is needed to prevent surface runoff bypass. Research is being conducted using multiple time domain reflectomete...

  9. Reinforcement of asphalt concrete pavement by segments of exhausted fiber used for sorption of oil spill

    NASA Astrophysics Data System (ADS)

    Lukashevich, V. N.; Efanov, I. N.

    2015-01-01

    The paper is aimed at construction of the experimental road pavement made of dispersed reinforced asphalt concrete. Electronic paramagnetic resonance, infrared spectroscopy and fluorescent bitumen studies were used to prove that disperse reinforcement of asphalt concrete mixtures with fibers of exhausted sorbents reduce the selective filtration of low polymeric fractions of petroleum bitumen and improve its properties in the adsorption layer. Sesquioxides are neutralized as catalysts aging asphalt binder. This leads to improvement in the elasticity of bitumen films at low temperatures and provide better crack resistance of coatings to reduce the intensity of the aging of asphalt binder, and, therefore, to increase the durability of road pavements. The experimental road pavement made of dispersed reinforced asphalt concrete operated during 4 years and demonstrated better transport- performance properties in comparison with the analogue pavements.

  10. Monitoring of the Permeable Pavement Demonstration Site at the Edison Environmental Center (Poster)

    EPA Science Inventory

    This is a poster on the permeable pavement parking lot at the Edison Environmental Center. The monitoring scheme for the project is discussed in-depth with graphics explaining the instrumentation installed at the site.

  11. Assessment of Clogging Dynamics in Permeable Pavement Systems with Time Domain Reflectometers

    EPA Science Inventory

    Infiltration is a primary functional mechanism in green infrastructure stormwater controls. This study used time domain reflectometers (TDRs) to measure spatial infiltration and assess clogging dynamics of permeable pavement systems in Edison, NJ, and Louisville, KY. In 2009, t...

  12. Generating enhanced site topography data to improve permeable pavement performance assessment methods - presentation

    EPA Science Inventory

    Permeable pavement surfaces are infiltration based stormwater control measures (SCM) commonly applied in parking lots to decrease impervious area and reduce runoff volume. Many are not optimally designed however, as little attention is given to draining a large enough contributin...

  13. Integration and road tests of a self-sensing CNT concrete pavement system for traffic detection

    NASA Astrophysics Data System (ADS)

    Han, Baoguo; Zhang, Kun; Burnham, Tom; Kwon, Eil; Yu, Xun

    2013-01-01

    In this paper, a self-sensing carbon nanotube (CNT) concrete pavement system for traffic detection is proposed and tested in a roadway. Pre-cast and cast-in-place self-sensing CNT concrete sensors were simultaneously integrated into a controlled pavement test section at the Minnesota Road Research Facility (MnROAD), USA. Road tests of the system were conducted by using an MnROAD five-axle semi-trailer tractor truck and a van, respectively, both in the winter and summer. Test results show that the proposed self-sensing pavement system can accurately detect the passing of different vehicles under different vehicular speeds and test environments. These findings indicate that the developed self-sensing CNT concrete pavement system can achieve real-time vehicle flow detection with a high detection rate and a low false-alarm rate.

  14. Use of Time Domain Reflectometers (TDRs) in Permeable Pavement Systems to Predict Maintenance Needs and Effectiveness

    EPA Science Inventory

    As the surface in permeable pavement systems clogs, infiltration capacity decreases, so maintenance is required to maintain hydrologic performance. There is limited direct guidance for determining when maintenance is needed to prevent surface runoff bypass. Research is being co...

  15. The Comparison of Measured and Simulated Dynamic Responses of Vehicles Indicated by Road Pavement Unevenness

    NASA Astrophysics Data System (ADS)

    Decký, Martin; Kováč, Matúš; Kotek, Peter

    2015-05-01

    The article presents the comparison of measured and simulated dynamic responses of heavy vehicle which are indicated by road pavement unevenness. This unevenness was represented by speed control bumps, potholes and stochastic pavement unevenness. The objective simulations were realized through the medium Quarter- Car Simulation by means of application of simulated theory of dynamic systems. The reliability of used model was verificated with comparison of measured and simulated values of sprung mass T815 vehicle accelerations. In the article, there are presented courses of total vertical forces of Quarter-Car Simulation for the first, the second and the fourth classification degree of unevenness, which was considered through the world's respected parameter IRI (International Roughness Index). Obtained simulated dynamic effects of the vehicle on the pavement were used for modification of a relevant Slovak design method of asphalt pavements.

  16. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems §...

  17. Theoretical analysis of piezoelectric energy harvesting from traffic induced deformation of pavements

    NASA Astrophysics Data System (ADS)

    Xiang, H. J.; Wang, J. J.; Shi, Z. F.; Zhang, Z. W.

    2013-09-01

    The problem of energy harvesting using piezoelectric transducers for pavement system applications is formulated with a focus on moving vehicle excitations. The pavement behavior is described by an infinite Bernoulli-Euler beam subjected to a moving line load and resting on a Winkler foundation. A closed-form dynamic response of the pavement is determined by a Fourier transform and the residue theorem. The voltage and power outputs of the piezoelectric harvester embedded in the pavements are then obtained by the direct piezoelectric effect. A comprehensive parametric study is conducted to show the effect of damping, the Winkler modulus, and the velocity of moving vehicles on the voltage and power output of the piezoelectric harvester. It is found that the output increases sharply when the velocity of the vehicle is close to the so-called critical velocity.

  18. Performance Prediction of the NCAT Test Track Pavements Using Mechanistic Models

    NASA Astrophysics Data System (ADS)

    LaCroix, Andrew Thomas

    In the pavement industry in the United States of America, there is an increasing desire to improve the pavement construction quality and life for new and rehabilitated pavements. In order to improve the quality of the pavements, the Federal Highway Administration (FHWA) has pursued a performance-related specification (PRS) for over 20 years. The goal of PRS is to provide material and construction (M/C) properties that correlate well with pavement performance. In order to improve upon the PRS projects developed in WesTrack (NCHRP 9-20) and the MEPDG-based PRS (NCHRP 9-22), a set of PRS tests and models are proposed to provide a critical link between pavement performance and M/C properties. The PRS testing is done using the asphalt mixture performance tester (AMPT). The proposed PRS focuses on rutting and fatigue cracking of asphalt mixtures. The mixtures are characterized for their stiffness, fatigue behavior, and rutting resistance using a dynamic modulus (|E*|) test, a fatigue test, and a triaxial stress sweep (TSS) test, respectively. Information from the fatigue test characterizes the simplified viscoelastic continuum damage (S-VECD) model. Once the stiffness is reduced to a certain level, the material develops macro-cracks and fails. The TSS test is used to characterize a viscoplastic (VP) model. The VP model allows the prediction of the rut depth beneath the center of the wheel. The VECD and VP models are used within a layered viscoelastic (LVE) pavement model to predict fatigue and rutting performance of pavements. The PRS is evaluated by comparing the predictions to the field performance at the NCAT pavement test track in Opelika, Alabama. The test track sections evaluated are part of the 2009 test cycle group experiment, which focused on WMA, high RAP (50%), and a combination of both. The fatigue evaluation shows that all sections would last at least 18 years at the same traffic rate. The sections do not show any cracking, suggesting the sections are well

  19. Desert Pavement Process and Form: Modes and Scales of Landscape Stability and Instability in Arid Regions

    NASA Astrophysics Data System (ADS)

    Wells, Stephen G.; McFadden, Leslie D.; McDonald, Eric V.; Eppes, Martha C.; Young, Michael H.; Wood, Yvonne A.

    2014-05-01

    Desert pavements are recognized in arid landscapes around the world, developing via diminution of constructional/depositional landform relief and creating a 1-2 stone thick armor over a "stone free" layer. Surface exposure dating demonstrates that clasts forming the desert pavements are maintained at the land surface over hundreds of thousands of years, as aeolian fines are deposited on the land surface, transported into the underlying parent material and incorporated into accretionary soil horizons (e.g., the stone free or vesicular [Av] horizon). This surface armor provides long-term stability over extensive regions of the landscape. Over shorter time periods and at the landform-element scale, dynamic surficial processes (i.e., weathering, runoff) continue to modify the pavement form. Clast size reduction in comparison to underlying parent material, along with armoring and packing of clasts in pavements contribute to their persistence, and studies of crack orientations in pavement clasts indicate physical weathering and diminution of particle size are driven by diurnal solar insolation. Over geologic time, cracks form and propagate from tensile stresses related to temporal and spatial gradients in temperature that evolve and rotate in alignment with the sun's rays. Observed multimodal nature of crack orientations appear related to seasonally varying, latitude-dependent temperature fields resulting from solar angle and weather conditions. Surface properties and their underlying soil profiles vary across pavement surfaces, forming a landscape mosaic and controlling surface hydrology, ecosystem function and the ultimate life-cycle of arid landscapes. In areas of well-developed pavements, surface infiltration and soluble salt concentrations indicate that saturated hydraulic conductivity of Av horizons decline on progressively older alluvial fan surfaces. Field observations and measurements from well-developed desert pavement surfaces landforms also yield

  20. Airport pavement roughness evaluation based on aircraft response

    NASA Astrophysics Data System (ADS)

    Dong, Qinxi; Hachiya, Yoshitaka; Endo, Katsura; Himeno, Kenji; Kawamura, Akira; Matsui, Kunihito

    2004-07-01

    Runway roughness affects primarily ride quality and dynamic wheel loads. The forces applied onto the airport pavement by aircraft vary instantaneously above and blow the static weight, which in turn increase the runway roughness. One method to effectively assess the ride quality of the airport runway is to measure its longitudinal profile and numerical simulate aircraft response performing a takeoff, landing or taxiing on that profile data. In this study the aircraft responses excited as the aircraft accelerates or moves at a constant speed on the runway during takeoff and taxi are computed by using the improved computer program TAXI. This procedure is capable of taking into account both the effects of discrete runway bumps and runway roughness. Thus, sections of significant dynamic response can be determined, and the maintenance and rehabilitation works for airport runways will be conducted.

  1. Friction evaluation of concrete paver blocks for airport pavement applications

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1992-01-01

    The development and use of concrete paver blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paver blocks installed in the track surface at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are described. Preliminary cornering performance results from testing of 40 x 14 radial-belted and bias-ply aircraft tires are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving several different tire sizes. Both dry and wet surface conditions were evaluated on the two concrete paver block test surfaces and a conventional, nongrooved Portland cement concrete surface. Future test plans involving evaluation of other concrete paver block designs at the ALDF are indicated.

  2. Cooler reflective pavements give benefits beyond energy savings: durability and illumination

    SciTech Connect

    Pomerantz, Melvin; Akbari, Hashem; Harvey, John T.

    2000-06-01

    City streets are usually paved with asphalt concrete because this material gives good service and is relatively inexpensive to construct and maintain. We show that making asphalt pavements cooler, by increasing their reflection of sunlight, may lead to longer lifetime of the pavement, lower initial costs of the asphalt binder, and savings on street lighting and signs. Excessive glare due to the whiter surface is not likely to be a problem.

  3. Adaptive road crack detection system by pavement classification.

    PubMed

    Gavilán, Miguel; Balcones, David; Marcos, Oscar; Llorca, David F; Sotelo, Miguel A; Parra, Ignacio; Ocaña, Manuel; Aliseda, Pedro; Yarza, Pedro; Amírola, Alejandro

    2011-01-01

    This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images with joints, sealed cracks and white painting, that usually generate false positive cracking. A seed-based approach is proposed to deal with road crack detection, combining Multiple Directional Non-Minimum Suppression (MDNMS) with a symmetry check. Seeds are linked by computing the paths with the lowest cost that meet the symmetry restrictions. The whole detection process involves the use of several parameters. A correct setting becomes essential to get optimal results without manual intervention. A fully automatic approach by means of a linear SVM-based classifier ensemble able to distinguish between up to 10 different types of pavement that appear in the Spanish roads is proposed. The optimal feature vector includes different texture-based features. The parameters are then tuned depending on the output provided by the classifier. Regarding non-crack features detection, results show that the introduction of such module reduces the impact of false positives due to non-crack features up to a factor of 2. In addition, the observed performance of the crack detection system is significantly boosted by adapting the parameters to the type of pavement. PMID:22163717

  4. Adaptive Road Crack Detection System by Pavement Classification

    PubMed Central

    Gavilán, Miguel; Balcones, David; Marcos, Oscar; Llorca, David F.; Sotelo, Miguel A.; Parra, Ignacio; Ocaña, Manuel; Aliseda, Pedro; Yarza, Pedro; Amírola, Alejandro

    2011-01-01

    This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images with joints, sealed cracks and white painting, that usually generate false positive cracking. A seed-based approach is proposed to deal with road crack detection, combining Multiple Directional Non-Minimum Suppression (MDNMS) with a symmetry check. Seeds are linked by computing the paths with the lowest cost that meet the symmetry restrictions. The whole detection process involves the use of several parameters. A correct setting becomes essential to get optimal results without manual intervention. A fully automatic approach by means of a linear SVM-based classifier ensemble able to distinguish between up to 10 different types of pavement that appear in the Spanish roads is proposed. The optimal feature vector includes different texture-based features. The parameters are then tuned depending on the output provided by the classifier. Regarding non-crack features detection, results show that the introduction of such module reduces the impact of false positives due to non-crack features up to a factor of 2. In addition, the observed performance of the crack detection system is significantly boosted by adapting the parameters to the type of pavement. PMID:22163717

  5. Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography

    NASA Astrophysics Data System (ADS)

    Dumoulin, Jean; Ibos, Laurent

    2010-05-01

    In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete

  6. Striated boulder pavements within glaciomarine diamicts of the Yakataga Formation, Middleton Island, Alaska

    SciTech Connect

    Eyles, C.H.

    1985-01-01

    The presence of striated boulder pavements in glacial sequences is often cited as evidence of transport and deposition by grounded glacier ice. However, recent reports show that striated pavements also form in non-glacial environments by the abrasion of boulder lag surfaces by floating glacier and seasonal ice. Several striated boulder pavements are identified within Early Pleistocene upper Yakataga Formation sediments exposed on Middleton Island close to the southern edge of the Gulf of Alaska continental shelf. The sequence is dominated by thick stratiform units of massive and stratified diamict formed by the settling of fine-grained sands and muds from suspension together with ice-rafted debris. Boulder pavements outcrop as extensive planar horizons within the diamicts, can be traced for several kilometers along strike and consist of single lines of clasts with faceted upper surfaces showing consistently oriented striation directions. Clasts are not preferentially aligned, however, and do not have the characteristic bullet shape of boulders transported at a glacier base and deposited by lodgement processes. Striated boulder pavements on Middleton Island appear to have formed as boulder lag surfaces generated by wave and tidal current reworking of diamict on relatively shallow banks. Lags were then overridden and abraded by a grounding ice shelf. The glacially-abraded boulder pavements on Middleton Island record the repeated expansion of a continuous ice shelf to the edge of the Gulf of Alaska continental shelf during the Early Pleistocene.

  7. Thermal Behavior of an Asphalt Pavement in the Laboratory and in the Parking Lot

    PubMed Central

    Martinkauppi, J. B.; Mäkiranta, A.; Kiijärvi, J.; Hiltunen, E.

    2015-01-01

    The urban, constructed areas are full of buildings and different kinds of pavements and have a noticeable lack of trees and flora. These areas are accumulating the heat from the Sun, people, vehicles, and constructions. One interesting heat collector is the asphalt pavement. How does the heat transfer to different layers under the pavement or does it? What are the temperatures under the pavement in Finland where the winter can be pretty hard? How can those temperatures be measured accurately? These are the main questions this paper gives the preliminary answers to. First the thermal behavior of asphalt and the layers beneath are researched in the laboratory and then the measurement field is bored and dug in the parking in the Western coast of Finland, 63°5′45′′ N. Distributed temperature sensing method was found to be a good choice for temperature measurements. Thermal behavior of pavement has been monitored in different layers and the preliminary results have been published here. The goal of this research is to assess the applicability of asphalt pavements for heat energy collection. PMID:25861679

  8. Greenhouse gas emissions of alternative pavement designs: framework development and illustrative application.

    PubMed

    Liu, Xiaoyu; Cui, Qingbin; Schwartz, Charles

    2014-01-01

    Pavement rehabilitation is carbon intensive and the choice of pavement type is a critical factor in controlling greenhouse gas (GHG) emissions. The existing body of knowledge is not able to support decision-making on pavement choice due to a lack of consensus on the system boundaries, the functional units and the estimation periods. Excessive data requirements further inhibit the generalization of the existing methodologies for design evaluation at the early planning stage. This study proposes a practical life-cycle GHG estimation approach, which is arguably effective to benchmark pavement emissions given project bid tabulation. A set of case studies conducted for this study suggest that recycled asphalt pavement (e.g., foam stabilized base (FSB), and warm mix asphalt (WMA)) would prevent up to 50% of GHGs from the initial construction phase. However, from a life-cycle perspective, pavement emissions are dictated largely by the traffic characteristics and the analysis period for the use phase. The benefits from using recycled materials (e.g., FSB) are likely to diminish if the recycled products do not perform as well as those properly proportioned with less recycled materials, or if the recycled materials are locally unavailable. When the AADT reaches 10,000, use phase releases more than 97% of the life cycle emissions and the emissions difference among alternative designs will be within 1%. PMID:24333742

  9. Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods.

    PubMed

    Li, Hui; Kayhanian, Masoud; Harvey, John T

    2013-03-30

    Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. PMID:23434738

  10. A real-time 3D scanning system for pavement rutting and pothole detections

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Yu, Wurong; Xu, Bugao

    2009-08-01

    Rutting and pothole are the common pavement distress problems that need to be timely inspected and repaired to ensure ride quality and safe traffic. This paper introduces a real-time, automated inspection system devoted for detecting these distress features using high-speed transverse scanning. The detection principle is based on the dynamic generation and characterization of 3D pavement profiles obtained from structured light measurements. The system implementation mainly involves three tasks: multi-view coplanar calibration, sub-pixel laser stripe location, and pavement distress recognition. The multi-view coplanar scheme was employed in the calibration procedure to increase the feature points and to make the points distributed across the field of view of the camera, which greatly improves the calibration precision. The laser stripe locating method was implemented in four steps: median filtering, coarse edge detection, fine edge adjusting, stripe curve mending and interpolation by cubic splines. The pavement distress recognition algorithms include line segment approximation of the profile, searching for the feature points, and parameters calculations. The parameter data of a curve segment between two feature points, such as width, depth and length, were used to differentiate rutting, pothole, and pothole under different constraints. The preliminary experiment results show that the system is capable of locating these pavement distresses, and meets the needs for real-time and accurate pavement inspection.

  11. Dust accretion under stone pavements: A complementary environmental archive in arid environments

    NASA Astrophysics Data System (ADS)

    Dietze, Michael; Fuchs, Markus; Kleber, Arno

    2014-05-01

    Stone pavements are widespread surface covers in arid environments. They form predominantly by the trapping of aeolian dust, which trickles below the surficial clast layer, where it forms a continuous layer of fine-grained material with a prominent foamy structure: the vesicular horizon (Av). Successive accretion of dust leads to a thickening of the aeolian mantle and detaches clasts from bedrock. Since this process is dependent on environmental conditions, stone pavement-covered accretionary sections can be used as palaeoenvironmental archive. In the eastern Mojave Desert, correlation of six sediment sections on a 560 ka old basalt flow yield a standard section, comprising at least three distinct units of pulsed aeolian sediment input, interrupted by phases of stone pavement formation, their burial and subsequent pedogenetic alteration. Formation and subsequent burial of stone pavements requires lateral re-formation processes. Two such processes - clast drag by unconcentrated overland flow and clast creep by air release from the soil - are presented, along with their environmental boundary conditions. The different sedimentary units under stone pavements in the eastern Mojave Desert must be interpreted in the light of both, the prominent climatic changes during the Pleistocene/Holocene and the young drainage system in this region. Accretionary dust sections under stone pavements receive their sediment predominantly from modern playas. However, they typically start trapping sediment and thus environmental information when the lake level drops and the lacustrine archive deceases. Hence, they appear to be complementary archives with a the potential to fill the stratigraphic gaps in lacustrine records.

  12. Thermal behavior of an asphalt pavement in the laboratory and in the parking lot.

    PubMed

    Martinkauppi, J B; Mäkiranta, A; Kiijärvi, J; Hiltunen, E

    2015-01-01

    The urban, constructed areas are full of buildings and different kinds of pavements and have a noticeable lack of trees and flora. These areas are accumulating the heat from the Sun, people, vehicles, and constructions. One interesting heat collector is the asphalt pavement. How does the heat transfer to different layers under the pavement or does it? What are the temperatures under the pavement in Finland where the winter can be pretty hard? How can those temperatures be measured accurately? These are the main questions this paper gives the preliminary answers to. First the thermal behavior of asphalt and the layers beneath are researched in the laboratory and then the measurement field is bored and dug in the parking in the Western coast of Finland, 63°5'45'' N. Distributed temperature sensing method was found to be a good choice for temperature measurements. Thermal behavior of pavement has been monitored in different layers and the preliminary results have been published here. The goal of this research is to assess the applicability of asphalt pavements for heat energy collection. PMID:25861679

  13. Pavement response to vehicular loads: a mechanistic approach involving nondestructive evaluation techniques

    NASA Astrophysics Data System (ADS)

    Kennedy, James C., Jr.

    1996-11-01

    The need for effective design in the nation's highways is greater now, more than ever, due to shrinking funds for new construction and rehabilitation/maintenance practices and the need to preserve the lands that are not now part of the roadway system. Most of the nation's highways were constructed within the last 30 years and many of these are due for significant rehabilitation and even reconstruction. Thus, the need to infuse robust design methods into these rehabilitation and reconstruction strategies is paramount. Currently, methods for cost allocation for pavement rehabilitation/maintenance activities and pavement management estimations are based on empirical and semi- empirical founded predictions that come up short, particularly when the roadway i subjected to multi-axle, heavy weight vehicles. Additionally, materials currently used int he construction of the pavement structure do not always behave in an elastic manner and the ability to predict the pavement response in the presence of other than elastic material behavior is essential. Finally, prediction of pavement states of distress based on empirical methods and elastic material behavior are inadequate, particularly when heavy weight vehicular traffic is involved. This paper includes descriptions of the overall methodology for pavement design and the unique requirements for the design and implementation of the structural and environmental sensing elements. Description of the mechanistic aspects in the software for the structural and material models is discussed and comparison of predicted and field measured results are presented.

  14. Recycled materials in asphalt pavements. October 1973-November 1989 (Citations from the NTIS data base). Report for October 1973-November 1989

    SciTech Connect

    Not Available

    1989-12-01

    This bibliography contains citations concerning the recycling of asphalt-pavement materials, and the use of other recycled materials to manufacture asphalt pavement. Articles discuss methods used for recycling bituminous pavement including hot-mix and cold-mix. Materials used to improve recycled pavement, and recycled materials used in asphalt pavement include latexes, rubber scrap such as tires, glass shards, concretes, dusts, waste oils, roofing wastes, sulfur, and metal refining sludges. Testing and evaluation of recycled pavements both in laboratories and in test cases are considered. (Contains 110 citations fully indexed and including a title list.)

  15. DESERT PAVEMENTS AND SOILS ON BASALTIC PYROCLASTIC DEPOSITS AT LATHROP WELLS AND RED CONE VOLCANOES, SOUTHERN NEVADA ABSTRACT

    SciTech Connect

    G.A. Valentine; C.D. Harrington

    2005-08-26

    Formation of desert pavement and accretionary soils are intimately linked in arid environments such as the Mojave Desert. Well-sorted fallout scoria lapilli at Lathrop Wells (75-80 ky) and Red Cone ({approx}1 Ma) volcanoes (southern Nevada) formed an excellent starting material for pavement, allowing infiltration of eolian silt and fine sand that first clogs the pore space of underlying tephra and then aggrades and develops vesicular A (Av) horizons. Variations in original pyroclast sizes provide insight into minimum and maximum clast sizes that promote pavement and soil formation: pavement becomes ineffective when clasts can saltate under the strongest winds, while clasts larger than coarse lapilli are unable to form an interlocking pavement that promotes silt accumulation (necessary for Av development). Contrary to predictions that all pavements above altitudes of {approx}400 m would have been ''reset'' in their development after late Pleistocene vegetation advances (about 15 ka), the soils and pavements show clear differences in maturity between the two volcanoes. This indicates that either the pavements/soils develop slowly over many 10,000's of years and then are very stable, or that, if they are disrupted by vegetation advances, subsequent pavements are reestablished with successively more mature characteristics.

  16. DESERT PAVEMENTS AND SOILS ON BASALTIC PYROCLASTIC DEPOSITS AT LATHROP WELLS AND RED CONE VOLCANOES, SOUTHERN NEVADA

    SciTech Connect

    G.A. Valentine; C.D. Harrington

    2005-08-10

    Formation of desert pavement and accretionary soils are intimately linked in arid environments such as the Mojave Desert. Well-sorted fallout scoria lapilli at Lathrop Wells (75-80 ky) and Red Cone ({approx}1 Ma) volcanoes (southern Nevada) formed an excellent starting material for pavement, allowing infiltration of eolian silt and fine sand that first clogs the pore space of underlying tephra and then aggrades and develops vesicular A (Av) horizons. Variations in original pyroclast sizes provide insight into minimum and maximum clast sizes that promote pavement and soil formation: pavement becomes ineffective when clasts can saltate under the strongest winds, while clasts larger than coarse lapilli are unable to form an interlocking pavement that promotes silt accumulation (necessary for Av development). Contrary to predictions that all pavements above altitudes of {approx}400 m would have been ''reset'' in their development after late Pleistocene vegetation advances (about 15 ka), the soils and pavements show clear differences in maturity between the two volcanoes. This indicates that either the pavement soils develop slowly over many 10,000's of years and then are very stable, or that, if they are disrupted by vegetation advances, subsequent pavements are reestablished with successively more mature characteristics.

  17. Effects of impervious pavements on reducing runoff in an arid urban catchment

    NASA Astrophysics Data System (ADS)

    Epshtein, O.; Turnbull, L.; Earl, S.

    2011-12-01

    The progressive urbanization of US arid and semi-arid southwestern territories has transformed undeveloped aridlands into dynamic, radially expanding metropolitan centers. As these mature, infill development further reduces undeveloped area, inversely coupling surface imperviousness to infiltration rates, with a subsequent increase in runoff generation. Intensified runoff carries undesirable environmental consequences, magnifying urban flooding events and concentrations, transport, and propagation of contaminants. Pervious pavements offer one potential solution for decreased urban infiltration. At present, the application potential of pervious pavements as an effective urban infiltration management tool exceeds its exploitation. While entirely eliminating urban Total Impervious Area is not a feasible solution, pervious pavements significantly reduce Effective Impervious Area at costs competitive with traditional Best Management Practices. Previous research into pervious pavements has largely consisted of laboratory prototypes or small-scale field experiments, with a heavy bias towards parking lots. In this study we explore the effectiveness of pervious pavements in increasing infiltration, thus decreasing runoff volume during summer monsoonal and winter convective rainfall events in an 8 ha residential catchment in Scottsdale, Arizona. Analysis focuses on the interaction dynamics between surface area of pervious pavement application and its net effect on runoff response at the catchment level. Hydrological response was modeled using MAHLERAN (Model for Assessing Hillslope-Landscape Erosion, Runoff and Nutrients), a spatially explicit, event-based model, parameterized at a spatial resolution of 0.25 sq m. Data for model parameterization was obtained from analysis of aerial imagery and field-based monitoring of surface properties. The model was tested against measurements of flow at the catchment outlet for multiple rainfall events with total event rainfall ranging

  18. On-site inspections of pavement damages evolution using GPR

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; D'Amico, Fabrizio; Calvi, Alessandro; Benedetto, Andrea

    2014-05-01

    Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of

  19. Surface runoff from full-scale coal combustion product pavements during accelerated loading

    SciTech Connect

    Cheng, C.M.; Taerakul, P.; Tu, W.; Zand, B.; Butalia, T.; Wolfe, W.; Walker, H.

    2008-08-15

    In this study, the release of metals and metalloids from full-scale portland cement concrete pavements containing coal combustion products (CCPs) was evaluated by laboratory leaching tests and accelerated loading of full-scale pavement sections under well-controlled conditions. An equivalent of 20 years of highway traffic loading was simulated at the OSU/OU Accelerated Pavement Load Facility (APLF). Three types of portland cement concrete driving surface layers were tested, including a control section (i.e., ordinary portland cement (PC) concrete) containing no fly ash and two sections in which fly ash was substituted for a fraction of the cement; i.e., 30% fly ash (FA30) and 50% fly ash (FA50). In general, the concentrations of minor and trace elements were higher in the toxicity characteristic leaching procedure (TCLP) leachates than in the leachates obtained from synthetic precipitation leaching procedure and ASTM leaching procedures. Importantly, none of the leachate concentrations exceeded the TCLP limits or primary drinking water standards. Surface runoff monitoring results showed the highest release rates of inorganic elements from the FA50 concrete pavement, whereas there were little differences in release rates between PC and FA30 concretes. The release of elements generally decreased with increasing pavement loading. Except for Cr, elements were released as particulates (>0.45 {mu} m) rather than dissolved constituents. The incorporation of fly ash in the PC cement concrete pavements examined in this study resulted in little or no deleterious environmental impact from the leaching of inorganic elements over the lifetime of the pavement system.

  20. Reduction of traffic and tire/pavement noise: 1st year results of the Arizona Quiet Pavement Program-Site III

    NASA Astrophysics Data System (ADS)

    Reyff, James A.; Donavan, Paul

    2005-09-01

    The Arizona Quiet Pavement Pilot Program overlaid major freeway segments in the Phoenix area with an Asphalt Rubber Friction Course (ARFC). The overlay was placed on various Portland Cement Concrete Pavement (PCCP) textures. Traffic noise reductions were evaluated by performing wayside traffic noise measurements and tire/pavement source level measurements. First year results for three different study sites are presented in this paper. Depending on the texture of the initial PCCP and microphone locations, reductions of up to 12 dBA in wayside traffic noise levels were measured. Similar reductions of tire/pavement source levels were measured. Results of the two methods are compared. Traffic conditions monitored during the measurements were modeled using the Federal Highway Administration's Traffic Noise Model (TNM 2.5) to compare modeled levels to those measured for PCCP and AFRC overlay conditions. The model under predicted levels for PCCP conditions and over predicted levels for AFRC conditions. The magnitude of under or over prediction varied with distance. The effect of propagation was examined and was aided by simultaneous measurements of wind conditions made by Arizona State University. TNM 2.5 was used to identify sound wall heights that were equivalent to the traffic noise reductions provided by the AFRC overlay.

  1. Composition.

    ERIC Educational Resources Information Center

    Nemanich, Donald, Ed.

    1974-01-01

    The articles in this special issue of the "Illinois English Bulletin" concern the state of composition instruction at the secondary and college levels. The titles and authors are "Monologues or Dialogues? A Plea for Literacy" by Dr. Alfred J. Lindsey, "Teaching Composition: Curiouser and Curiouser" by Denny Brandon, and "Teaching Writing to High…

  2. Investigation of antenna frequency impact on assessing voids of asphalt pavements using GPR

    NASA Astrophysics Data System (ADS)

    Plati, C.; Georgouli, K.; Loizos, A.

    2012-04-01

    Ground Penetrating Radar (GPR) is a Non Destructive Testing (NDT) technique that has been developed and improved upon over the past 30 years. The technique is frequently utilized in order to evaluate and assess pavement structures. GPR, for pavement evaluation purposes, can be described as a remote sensing system that emits a short pulse, of electromagnetic energy, into the pavement, with a central frequency varying from 10 MHz up to 2.5GHz. The two most commonly utilized setups are air-coupled and ground-coupled antenna systems. For air-coupled systems, the antennas are suspended above the pavement surface and can operate at normal traffic speeds (up to ~ 80 Km/h). The major drawback of the air-coupled antenna is that penetration depth is limited. On the other hand, for ground-coupled systems the antennas are in direct contact with the pavement surface, providing for better signal penetration into the pavement structure; however ground coupled systems can achieve only limited operational speeds. As a generalized rule, increasing the GPR central operating frequency, increases the investigation resolution, while decreasing the overall depth of investigation In the light of the above, air-coupled systems have become increasingly popular for the evaluation of the part of the pavement structure, especially for the asphalt layers, while ground-coupled systems are utilized mostly in order to gather information from the entire pavement structure (up to ~ 3 m depth). The majority of GPR pavement studies are carried out with air-coupled horn antennas, as they can be implemented at driving speeds without need for road closures. For instance, the 1 GHz air-coupled horn antenna is commonly used for the estimation of pavement layer thickness. However signals generated by horn antenna systems must have sufficient quality to allow the performance of automated signal processing and qualitative data analysis, especially when pavement data more sensitive to the analysis parameters

  3. Recycling of plastic and rubber tire waste in asphalt pavements

    SciTech Connect

    Morrison, G.R.; Lee, N.K.; Hesp, S.A.M.

    1994-12-31

    This paper discusses some important issues related to the use of recycled thermoplastics and rubber tire waste in asphalt binders for hot-mix pavements. Both high temperature rheological and low temperature fracture studies are presented on recycled polyethylene, devulcanized and crumb rubber-modified asphalt binders. The results are compared to unmodified and commercially available modified binders. This research is especially timely in light of the US Intermodal Surface Transportation Efficiency Act of 1991, Section 1038 which, starting in 1995, will force state and local governments to use significant amounts of recycled rubber tire or plastic waste in federally funded highway projects. High temperature rheological measurements of the loss modulus, loss tangent and complex modulus show a significant improvement when only small quantities of crumb rubber, devulcanized crumb rubber or waste polyethylene are added to the asphalt binders. The low temperature fracture performance of the modified asphalts is greatly influenced by the interfacial strength between the dispersed and continuous phase. The fracture toughness increases dramatically, only when low molecular weight polymers are grafted in-situ onto the rubber and polymer dispersed phases in order to strength the interface. This points to a crack-pinning mechanism as being responsible for the dramatic increase in fracture toughness that is observed in this work. Single phase, devulcanized crumb rubber-asphalt systems perform quite poorly at low temperatures.

  4. Leaching of organic contaminants from storage of reclaimed asphalt pavement.

    PubMed

    Norin, Malin; Strömvall, A M

    2004-03-01

    Recycling of asphalt has been promoted by rapid increases in both the use and price of petroleum-based bitumen. Semi-volatile organic compounds in leachates from reclaimed asphalt pavement, measured in field samples and in laboratory column test, were analysed through a GC/MS screen-test methodology. Sixteen PAH (polyaromatic hydrocarbons) were also analysed in leachates from the column study. The highest concentrations of semi-volatile compounds, approximately 400 microg l(-1), were measured in field samples from the scarified stockpile. Naphthalene, butylated hydroxytoluene (BHT) and dibutyl phthalate (DBP) were the most dominant of the identified semi-volatiles. The occurrence of these compounds in urban groundwater, also indicate high emission rates and persistent structures of the compounds, making them potentially hazardous. Car exhausts, rubber tires and the asphalt material itself are all probable emission sources, determined from the organic contaminants released from the stockpiles. The major leaching mechanism indicated was dissolution of organic contaminants from the surface of the asphalt gravels. In the laboratory column test, the release of high-molecular weight and more toxic PAH was higher in the leachates after two years than at the commencement of storage. The concentrations of semi-volatiles in leachates, were also several times lower than those from the field stockpile. These results demonstrate the need to follow up laboratory column test with real field measurements. PMID:15176747

  5. Road roughness evaluation using in-pavement strain sensors

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiming; Deng, Fodan; Huang, Ying; Bridgelall, Raj

    2015-11-01

    The international roughness index (IRI) is a characterization of road roughness or ride quality that transportation agencies most often report. The prevalent method of acquiring IRI data requires instrumented vehicles and technicians with specialized training to interpret the results. The extensive labor and high cost requirements associated with the existing approaches limit data collection to at most once per year for portions of the national highway system. Agencies characterize roughness only for some secondary roads but much less frequently, such as once every five years, resulting in outdated roughness information. This research developed a real-time roughness evaluation approach that links the output of durable in-pavement strain sensors to prevailing indices that summarize road roughness. Field experiments validated the high consistency of the approach by showing that it is within 3.3% of relative IRI estimates. After their installation and calibration during road construction, the ruggedized strain sensors will report road roughness continuously. Thus, the solution will provide agencies a real-time roughness monitoring solution over the remaining service life of road assets.

  6. The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China.

    PubMed

    Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

    2016-01-01

    This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO₂e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO₂e is 8215.31 tons. Based on the evaluation results, the CO₂e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO₂e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO₂e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO₂ in each phase, which accounts for more than 98% of total emissions. N₂O and CH₄ emissions are relatively insignificant. PMID:27347987

  7. PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

    USGS Publications Warehouse

    Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.

    2009-01-01

    We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

  8. Research on tensile strength characteristics of bridge deck pavement bonding layers

    NASA Astrophysics Data System (ADS)

    Wu, Shaopeng; Han, Jun

    2010-03-01

    As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

  9. Research on tensile strength characteristics of bridge deck pavement bonding layers

    NASA Astrophysics Data System (ADS)

    Wu, Shaopeng; Han, Jun

    2009-12-01

    As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

  10. Effects on evaporation rates from different water-permeable pavement designs.

    PubMed

    Starke, P; Göbel, P; Coldewey, W G

    2011-01-01

    The urban water balance can be attenuated to the natural by water-permeable pavements (WPPs). Furthermore, WPPs have a 16% higher evaporation rate than impermeable pavements, which can lead to a better urban climate. Evaporation rates from pavements are influenced by the pavement surface and by the deeper layers. By a compared evaporation measurement between different WPP designs, the grain size distribution of the sub-base shows no influence on the evaporation rates in a significant way. On the contrary, a sub-base made of a twin-layer decreases the evaporation by 16% compared to a homogeneous sub-base. By a change in the colour of the paving stone, 19% higher evaporation rates could be achieved. A further comparison shows that the transpiration-effect of the grass in grass pavers increases the evaporation rates more than threefold to pervious concrete pavements. These high evapotranspiration rates can not be achieved with a pervious concrete paving stone. In spite of this, the broad field of application of the pervious concrete paving stone increases the importance in regard to the urban climate. PMID:22049757

  11. Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway

    PubMed Central

    Pascucci, Simone; Bassani, Cristiana; Palombo, Angelo; Poscolieri, Maurizio; Cavalli, Rosa

    2008-01-01

    This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads' asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strictly related to the decrease of oily components that cause an increase of the abundance of surfacing limestone, the diagnostic absorption emissivity peak at 11.2μm of the limestone was used for retrieving from MIVIS emissivity data the areas exhibiting defects on asphalt pavements surface.The results showed that MIVIS emissivity allows establishing a threshold that points out those asphalt road sites on which a check for a maintenance intervention is required. Therefore, this technique can supply local government authorities an efficient, rapid and repeatable road mapping procedure providing the location of the asphalt pavements to be checked.

  12. A real-time 3D scanning system for pavement distortion inspection

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Xu, Bugao

    2010-01-01

    Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement.

  13. Life Cycle Assessment of Pavements: A Critical Review of Existing Literature and Research

    SciTech Connect

    Santero, Nicholas; Masanet, Eric; Horvath, Arpad

    2010-04-20

    This report provides a critical review of existing literature and modeling tools related to life-cycle assessment (LCA) applied to pavements. The review finds that pavement LCA is an expanding but still limited research topic in the literature, and that the existing body of work exhibits methodological deficiencies and incompatibilities that serve as barriers to the widespread utilization of LCA by pavement engineers and policy makers. This review identifies five key issues in the current body of work: inconsistent functional units, improper system boundaries, imbalanced data for asphalt and cement, use of limited inventory and impact assessment categories, and poor overall utility. This review also identifies common data and modeling gaps in pavement LCAs that should be addressed in future work. These gaps include: the use phase (rolling resistance, albedo, carbonation, lighting, leachate, and tire wear and emissions), asphalt fumes, feedstock energy of bitumen, traffic delay, the maintenance phase, and the end-of-life phase. This review concludes with a comprehensive list of recommendations for future research, which shed light on where improvements in knowledge can be made that will benefit the accuracy and comprehensiveness of pavement LCAs moving forward.

  14. PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States

    SciTech Connect

    Peter C. Van Metre; Barbara J. Mahler; Jennifer T. Wilson

    2009-01-15

    We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U.S. cities that show nationwide patterns in concentrations of {Sigma}PAHs associated with sealcoat. Dust was swept from parking lots in six cities in the central and eastern U.S., where coal-tar-based sealcoat dominates use, and three cities in the western U.S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2.1 and 0.8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo(a)pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted. 30 refs., 4 figs., 2 tabs.

  15. The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China

    PubMed Central

    Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

    2016-01-01

    This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO2e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO2e is 8215.31 tons. Based on the evaluation results, the CO2e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO2e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO2e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO2 in each phase, which accounts for more than 98% of total emissions. N2O and CH4 emissions are relatively insignificant. PMID:27347987

  16. The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring - Paper

    EPA Science Inventory

    There exist few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage condit...

  17. The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring - Slides

    EPA Science Inventory

    There exist few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage condit...

  18. Mechanics based model for predicting structure-induced rolling resistance (SRR) of the tire-pavement system

    NASA Astrophysics Data System (ADS)

    Shakiba, Maryam; Ozer, Hasan; Ziyadi, Mojtaba; Al-Qadi, Imad L.

    2016-05-01

    The structure-induced rolling resistance of pavements, and its impact on vehicle fuel consumption, is investigated in this study. The structural response of pavement causes additional rolling resistance and fuel consumption of vehicles through deformation of pavement and various dissipation mechanisms associated with inelastic material properties and damping. Accurate and computationally efficient models are required to capture these mechanisms and obtain realistic estimates of changes in vehicle fuel consumption. Two mechanistic-based approaches are currently used to calculate vehicle fuel consumption as related to structural rolling resistance: dissipation-induced and deflection-induced methods. The deflection-induced approach is adopted in this study, and realistic representation of pavement-vehicle interactions (PVIs) is incorporated. In addition to considering viscoelastic behavior of asphalt concrete layers, the realistic representation of PVIs in this study includes non-uniform three-dimensional tire contact stresses and dynamic analysis in pavement simulations. The effects of analysis type, tire contact stresses, pavement viscoelastic properties, pavement damping coefficients, vehicle speed, and pavement temperature are then investigated.

  19. Improved Crack Type Classification Neural Network based on Square Sub-images of Pavement Surface

    NASA Astrophysics Data System (ADS)

    Lee, Byoung Jik; Lee, Hosin “David”

    The previous neural network based on the proximity values was developed using rectangular pavement images. However, the proximity value derived from the rectangular image was biased towards transverse cracking. By sectioning the rectangular image into a set of square sub-images, the neural network based on the proximity value became more robust and consistent in determining a crack type. This paper presents an improved neural network to determine a crack type from a pavement surface image based on square sub-images over the neural network trained using rectangular pavement images. The advantage of using square sub-image is demonstrated by using sample images of transverse cracking, longitudinal cracking and alligator cracking.

  20. Road pavement condition mapping and assessment using remote sensing data based on MESMA

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Zhang, X.; Jin, X.; Yu, H.; Rao, J.; Tian, S.; Luo, L.; Li, C.

    2016-04-01

    Remote sensing can be used to monitor changes of asphalt pavement condition because of the spectral change of aged asphalt material. However, owing to coarse spatial resolution of images and the limited width of roads ambient land cover types (e.g. vegetation, buildings, and soil) affect the spectral signal and add significant variability and uncertainty to analysis of road conditions. To overcome this problem, Multiple Endmember Spectral Mixture Analysis (MESMA) was tested to map asphalt pavement condition using WorldView-2 satellite imagery with eight bands spanning from visible to near infrared. Results indicated that MESMA run in a three-endmember model models mixed-pavement pixels well with a low average RMSE (0.01).

  1. Semi-Automatic Road/Pavement Modeling using Mobile Laser Scanning

    NASA Astrophysics Data System (ADS)

    Hervieu, A.; Soheilian, B.

    2013-10-01

    Scene analysis, in urban environments, deals with street modeling and understanding. A street mainly consists of roadways, pavements (i.e., walking areas), facades, still and moving obstacles. In this paper, we investigate the surface modeling of roadways and pavements using LIDAR data acquired by a mobile laser scanning (MLS) system. First, road border detection is considered. A system recognizing curbs and curb ramps while reconstructing the missing information in case of occlusion is presented. A user interface scheme is also described, providing an effective tool for semi-automatic processing of large amount of data. Then, based upon road edge information, a process that reconstructs surfaces of roads and pavements has been developed, providing a centimetric precision while reconstructing missing information. This system hence provides an important knowledge of the street, that may open perspectives in various domains such as path planning or road maintenance.

  2. Comparative Evaluation of Pavement Crack Detection Using Kernel-Based Techniques in Asphalt Road Surfaces

    NASA Astrophysics Data System (ADS)

    Miraliakbari, A.; Sok, S.; Ouma, Y. O.; Hahn, M.

    2016-06-01

    With the increasing demand for the digital survey and acquisition of road pavement conditions, there is also the parallel growing need for the development of automated techniques for the analysis and evaluation of the actual road conditions. This is due in part to the resulting large volumes of road pavement data captured through digital surveys, and also to the requirements for rapid data processing and evaluations. In this study, the Canon 5D Mark II RGB camera with a resolution of 21 megapixels is used for the road pavement condition mapping. Even though many imaging and mapping sensors are available, the development of automated pavement distress detection, recognition and extraction systems for pavement condition is still a challenge. In order to detect and extract pavement cracks, a comparative evaluation of kernel-based segmentation methods comprising line filtering (LF), local binary pattern (LBP) and high-pass filtering (HPF) is carried out. While the LF and LBP methods are based on the principle of rotation-invariance for pattern matching, the HPF applies the same principle for filtering, but with a rotational invariant matrix. With respect to the processing speeds, HPF is fastest due to the fact that it is based on a single kernel, as compared to LF and LBP which are based on several kernels. Experiments with 20 sample images which contain linear, block and alligator cracks are carried out. On an average a completeness of distress extraction with values of 81.2%, 76.2% and 81.1% have been found for LF, HPF and LBP respectively.

  3. Oxygen demand of aircraft and airfield pavement deicers and alternative freezing point depressants

    USGS Publications Warehouse

    Corsi, Steven R.; Mericas, Dean; Bowman, George

    2012-01-01

    Aircraft and pavement deicing formulations and other potential freezing point depressants were tested for biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Propylene glycol-based aircraft deicers exhibited greater BOD5 than ethylene glycol-based aircraft deicers, and ethylene glycol-based products had lower degradation rates than propylene glycol-based products. Sodium formate pavement deicers had lower COD than acetate-based pavement deicers. The BOD and COD results for acetate-based pavement deicers (PDMs) were consistently lower than those for aircraft deicers, but degradation rates were greater in the acetate-based PDM than in aircraft deicers. In a 40-day testing of aircraft and pavement deicers, BOD results at 20°C (standard) were consistently greater than the results from 5°C (low) tests. The degree of difference between standard and low temperature BOD results varied among tested products. Freshwater BOD test results were not substantially different from marine water tests at 20°C, but glycols degraded slower in marine water than in fresh water for low temperature tests. Acetate-based products had greater percentage degradation than glycols at both temperatures. An additive component of the sodium formate pavement deicer exhibited toxicity to the microorganisms, so BOD testing did not work properly for this formulation. BOD testing of alternative freezing point depressants worked well for some, there was little response for some, and for others there was a lag in response while microorganisms acclimated to the freezing point depressant as a food source. Where the traditional BOD5 test performed adequately, values ranged from 251 to 1,580 g/kg. Where the modified test performed adequately, values of BOD28 ranged from 242 to 1,540 g/kg.

  4. Composites

    SciTech Connect

    Chou, T.; McCullough, R.L.; Pipes, R.B.

    1986-10-01

    The degree of control over material properties that is typified by hybrid composites is transforming engineering design. In part because homogeneous materials such as metals and alloys do not offer comparable control, specifying a material and designing a component have traditionally taken place separately. As composites begin to replace traditional materials in fields and such as aerospace, component design and the specification of a material are merging and becoming aspects of a single process. The controllable microstructure of a composite allows it to be tailored to match the distribution of stresses to which it will be subject. At the same time components must come to reflect the distinctive nature of composites: their directional properties and the intricate forms they can be given through processes such as injection molding, filament winding and three-dimensional weaving. The complexity inherent in conceiving components and their materials at the same time suggests engineering design will grow increasingly dependent on computers and multidisciplinary teams. Such an approach will harness the full potential of composites for the technologies of the future. 10 figures.

  5. Coal-tar-based pavement sealcoat—Potential concerns for human health and aquatic life

    USGS Publications Warehouse

    Mahler, Barbara J.; Woodside, Michael D.; Van Metre, Peter C.

    2016-01-01

    Aquatic Life Concerns—Runoff from coal-tar-sealcoated pavement, even runoff collected more than 3 months after sealcoat application, is acutely toxic to fathead minnows and water fleas, two species commonly used to assess toxicity to aquatic life. Exposure to even highly diluted runoff from coal-tar-sealcoated pavement can cause DNA damage and impair DNA repair. These findings demonstrate that coal-tar-sealcoat runoff can remain a risk to aquatic life for months after application.

  6. Hot bituminous pavement recycling US-56, Edwards and Pawnee counties, Kansas. Final report 1989-1993

    SciTech Connect

    Fager, G.A.; Maag, R.G.

    1993-10-01

    A study was undertaken between 1978 and 1993 to construct and monitor a hot recycle section. One hot recycle test section and one control section were completed in 1978 and monitored for cracking for approximately 12 years. This project was the first hot recycle project constructed in Kansas and one of the first in the United States. Using the experimental cost data and only cracking to determine pavement life, this hot recycle project was not economically feasible. Wheelpath rutting was not a problem throughout the life of both pavements. Opacity and particulate requirements were never met on this first hot recycle project. Due to the many unknowns, the project was considered a success.

  7. Enhancing the resolution of gpr spectra for pavement engineering applications

    NASA Astrophysics Data System (ADS)

    Benedetto, F.; Benedetto, A.

    2012-04-01

    Ground Penetrating Radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation and detects the reflected signals from subsurface structures. It can detect objects, changes in material, and voids and cracks. GPR has many applications in a number of fields. In the field of civil engineering one of the most advanced technologies used for road pavement monitoring is based on the deployment of advanced GPR systems. One of the most relevant causes of road pavement damage is often referable to water intrusion in structural layers. In this context, GPR has been recently proposed as a method to estimate moisture content in a porous medium without preventive calibration. Hence, the development of methods to obtain an estimate of the moisture content is a crucial research field involving economic, social and strategic aspects in road safety for a great number of public and private Agencies. In particular, a recent new approach was proposed to estimate moisture content in a porous medium basing on the theory of Rayleigh scattering, showing a shift of the frequency peak of the GPR spectrum towards lower frequencies as the moisture content increases in the soil. The weakness characterizing this approach is represented by the needs of high resolution signals, whereas GPR spectra are affected by low resolution. Hence, the rising requirement for high resolution leads to specific demands for improved prediction methods. Recently, a new technique combining the response of the conventional fast Fourier transform (FFT, well known for its high-precision receiving signal level) with that of the MUSIC (multiple signal classification) algorithm, well known for its super-resolution capacity has been proposed. This combined method has been proved to obtain a high precision level in quantifying the shift of the frequency peak of the GPR spectrum. This combined method can perform a reliable coarse estimate of

  8. Millimeter-wave nondestructive evaluation of pavement conditions

    NASA Astrophysics Data System (ADS)

    Vines-Cavanau, David; Busuioc, Dan; Birken, Ralf; Wang, Ming

    2012-04-01

    The United States is suffering from an aging civil infrastructure crisis. Key to recovery are rapid inspection technologies like that being investigated by the VOTERS project (Versatile Onboard Traffic Embedded Roaming Sensors), which aims to outfit ordinary road vehicles with compact low-cost hardware that enables them to rapidly assess and report the condition of roadways and bridge decks free of driver interaction. A key piece of hardware, and the focus of this paper, is a 24 GHz millimeter-wave radar system that measures the reflectivity of pavement surfaces. To account for the variability of real-world driving, such as changes in height, angle, speed, and temperature, a sensor fusion approach is used that corrects MWR measurements based on data from four additional sensors. The corrected MWR measurements are expected to be useful for various characterization applications, including: material type; deterioration such as cracks and potholes; and surface coverage conditions such as dry, wet, oil, water, and ice. Success at each of these applications is an important step towards achieving the VOTERS objective, however, this paper focuses on surface coverage, as whatever covers the driving surface will be most apparent to the MWR sensor and if not accounted for could significantly limit the accuracy of other applications. Contributions of the paper include findings from static lab tests, which validate the approach and show the effects of height and angle. Further contributions come from lab and in-field dynamic tests, which show the effects of speed and demonstrate that the MWR approach is accurate under city driving conditions.

  9. A comprehensive approach for the assessment of in-situ pavement density using GPR technique

    NASA Astrophysics Data System (ADS)

    Plati, Christina; Georgiou, Panos; Loizos, Andreas

    2013-04-01

    Proper construction of the asphalt pavement is a prerequisite to developing a long lasting roadway that does not require extensive future maintenance. This goal is achieved by verifying that design specifications are met through the use of quality assurance (QA) practices. The in-situ density is regarded as one of the most important controls used to ensure that a pavement being placed is of high quality because it is a good indicator of future performance. In-situ density is frequently assessed utilizing one or more of the following three methods: cores, nuclear density gauge measurements or non-nuclear density gauge measurements. Each of the above mentioned methods, however, have their distinct disadvantages. Cores, for example, are generally considered to be the most accurate means of measuring in-situ density, however, they are a time consuming and destructive test that introduces a defect into asphalt pavements. Because of the destructive nature associated with coring, contractors and agencies have alternatively used non-destructive nuclear and non-nuclear density gauges for quality control purposes. These instruments allow for a more rapid assessment of the in-situ density, allowing measurements to be taken even during the pavement's construction. The disadvantage of these gauges are that they provide density readings only at discrete locations of the asphalt pavement mat, while no consensus exists among pavement researchers on the proper correlation between the gauges and core density. In recent years, numerous alternative methods have been introduced for the assessment of in-situ density, both during asphalt pavement construction and afterwards. These methods include, amongst others, intelligent compaction, thermal imaging and ground penetrating radar (GPR). Among these methods, GPR has been defined as both a technically feasible and promising method for the nondestructive, rapid, and continuous evaluation of in-situ asphalt pavement density based on

  10. Cosmogenic {sup 3}He surface-exposure dating of stone pavements. Implications for landscape evolution in deserts

    SciTech Connect

    Wells, S.G.; McFadden, L.D.; Poths, J.; Olinger, C.T.

    1995-07-01

    The formation of stone pavements, a ubiquitous gravel armor mantling landforms in arid regions of the world, has been previously attributed to erosion by wind and water or alternating shrinking and swelling of soil horizons, implying that gravel is concentrated at the land surface in a time-transgressive manner. A newly proposed model for pavement evolution differs from these models in that pavement clasts are continuously maintained at the land surface in response to deposition and pedogenic modification of windblown dust. In-situ cosmogenic {sup 3}He surface-exposure ages on volcanic and alluvial landforms in the Mojave Desert of California are used to understand pavement evolution over geologic time scales and to test this new model. These exposure ages are stratigraphically consistent, show internal consistency at each site, and, for stone pavements adjacent to pristine, continuously exposed volcanic bedrock, are indistinguishable at the 1{sigma} level. We conclude that stone pavements are born at the surface and that pavements may provide one of the longest-term records of geologic, hydrologic, and climatic processes operating on desert surfaces. 23 refs., 3 figs., 1 tab.

  11. Composites

    NASA Astrophysics Data System (ADS)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  12. Automatic processing and modeling of GPR data for pavement thickness and properties

    NASA Astrophysics Data System (ADS)

    Olhoeft, Gary R.; Smith, Stanley S., III

    2000-04-01

    A GSSI SIR-8 with 1 GHz air-launched horn antennas has been modified to acquire data from a moving vehicle. Algorithms have been developed to acquire the data, and to automatically calibrate, position, process, and full waveform model it without operator intervention. Vehicle suspension system bounce is automatically compensated (for varying antenna height). Multiple scans are modeled by full waveform inversion that is remarkably robust and relatively insensitive to noise. Statistical parameters and histograms are generated for the thickness and dielectric permittivity of concrete or asphalt pavements. The statistical uncertainty with which the thickness is determined is given with each thickness measurement, along with the dielectric permittivity of the pavement material and of the subgrade material at each location. Permittivities are then converted into equivalent density and water content. Typical statistical uncertainties in thickness are better than 0.4 cm in 20 cm thick pavement. On a Pentium laptop computer, the data may be processed and modeled to have cross-sectional images and computed pavement thickness displayed in real time at highway speeds.

  13. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972..., as a basic framework for a PMS: (1) A database and an ongoing program for the collection...

  14. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972..., as a basic framework for a PMS: (1) A database and an ongoing program for the collection...

  15. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972..., as a basic framework for a PMS: (1) A database and an ongoing program for the collection...

  16. Technical Note: Outlays on Construction of Airport Runways with Prestressed and Dowelled Pavements

    NASA Astrophysics Data System (ADS)

    Więckowski, Andrzej; Sznurawa, Alicja

    2015-09-01

    For two variants of runways with abrasive concrete pavements in the prestressed and dowelled technologies, analyses have been presented regarding labour, materials, use of machinery, and financial outlays, together with the necessary technological-organisational analyses and assessment of work execution cycles, by the example of construction of a runway at the Katowice Airport.

  17. Analysis of durability of advanced cementitious materials for rigid pavement construction in California

    SciTech Connect

    Kurtis, K.E.; Monteiro, P.

    1999-04-01

    Caltrans specifications for the construction of rigid pavements require rapid setting, high early strength, superior workability concrete with a desired 30+ year service life. These strict specifications provide the motivations for the investigation of advanced cementitious materials for pavement construction. The cementitious materials under consideration by Caltrans may be classified into four categories: Portland cements and blends, calcium aluminate cements and blends, calcium sulfoaluminate cements, and fly ash-based cements. To achieve the desired 30+ year design life, it is essential to select materials that are expected to exhibit long-term durability. Because most of the cementitious materials under consideration have not been extensively used for pavement construction in the United States, it is essential to characterize the long-term durability of each material. This report provides general information concerning the deleterious reactions that may damage concrete pavements in California. The reactions addressed in this report are sulfate attack, aggregate reactions, corrosion of reinforcing steel, and freeze-thaw action. Specifically, the expected performance of Portland cements and blends, calcium aluminate cements and blends, calcium sulfoaluminate cements, and fly ash-based cements are examined with regard to each of the deleterious reactions listed. Additional consideration is given to any deterioration mechanism that is particular to any of these cement types. Finally, the recommended test program for assessing potential long-term durability with respect to sulfate attack is described.

  18. Dynamic Response of a Rigid Pavement Plate Based on an Inertial Soil

    PubMed Central

    Gibigaye, Mohamed; Yabi, Crespin Prudence; Alloba, I. Ezéchiel

    2016-01-01

    This work presents the dynamic response of a pavement plate resting on a soil whose inertia is taken into account in the design of pavements by rational methods. Thus, the pavement is modeled as a thin plate with finite dimensions, supported longitudinally by dowels and laterally by tie bars. The subgrade is modeled via Pasternak-Vlasov type (three-parameter type) foundation models and the moving traffic load is expressed as a concentrated dynamic load of harmonically varying magnitude, moving straight along the plate with a constant acceleration. The governing equation of the problem is solved using the modified Bolotin method for determining the natural frequencies and the wavenumbers of the system. The orthogonal properties of eigenfunctions are used to find the general solution of the problem. Considering the load over the center of the plate, the results showed that the deflections of the plate are maximum about the middle of the plate but are not null at its edges. It is therefore observed that the deflection decreased 18.33 percent when the inertia of the soil is taken into account. This result shows the possible economic gain when taking into account the inertia of soil in pavement dynamic design. PMID:27382639

  19. Water Quality Performance of Three Side-by-Side Permeable Pavement Surface Materials: Three Year Update

    EPA Science Inventory

    Communities are increasingly installing structural low impact development (LID) practices to mange stormwater and reduce pollutant loads associated with stormwater runoff. Permeable pavement is a LID practice that has limited research on working-scale, side-by-side performance o...

  20. Hydrologic and Pollutant Removal Performance of a Full-Scale, Fully Functional Permeable Pavement Parking Lot

    EPA Science Inventory

    In accordance with the need for full-scale, replicated studies of permeable pavement systems used in their intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditions, and maintenance regimes to evaluate these systems, the EPA’s Urb...

  1. Methods to Use Surface Infiltration Tests in Permeable Pavement Systems to Determine Maintenance Frequency

    EPA Science Inventory

    Currently, there is limited guidance on selecting test sites to measure surface infiltration rates in permeable pavement systems to determine maintenance frequency. The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete suggest to either (1) p...

  2. Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System - abstract

    EPA Science Inventory

    Studies on quantifying evaporation in permeable pavement systems are limited to few laboratory studies that used a scale to weigh evaporative losses and a field application with a tunnel-evaporation gauge. A primary objective of this research was to quantify evaporation for a la...

  3. Dynamic Response of a Rigid Pavement Plate Based on an Inertial Soil.

    PubMed

    Gibigaye, Mohamed; Yabi, Crespin Prudence; Alloba, I Ezéchiel

    2016-01-01

    This work presents the dynamic response of a pavement plate resting on a soil whose inertia is taken into account in the design of pavements by rational methods. Thus, the pavement is modeled as a thin plate with finite dimensions, supported longitudinally by dowels and laterally by tie bars. The subgrade is modeled via Pasternak-Vlasov type (three-parameter type) foundation models and the moving traffic load is expressed as a concentrated dynamic load of harmonically varying magnitude, moving straight along the plate with a constant acceleration. The governing equation of the problem is solved using the modified Bolotin method for determining the natural frequencies and the wavenumbers of the system. The orthogonal properties of eigenfunctions are used to find the general solution of the problem. Considering the load over the center of the plate, the results showed that the deflections of the plate are maximum about the middle of the plate but are not null at its edges. It is therefore observed that the deflection decreased 18.33 percent when the inertia of the soil is taken into account. This result shows the possible economic gain when taking into account the inertia of soil in pavement dynamic design. PMID:27382639

  4. Monitoring of the permeable pavement demonstration site at Edison Environmental Center

    EPA Science Inventory

    The EPA’s Urban Watershed Management Branch has installed an instrumented, working full-scale 110-space pervious pavement parking lot and has been monitoring several environmental stressors and runoff. This parking lot demonstration site has allowed the investigation of differenc...

  5. Monitoring Strategies in Permeable Pavement Systems to Optimize Maintenance Scheduling - abstract

    EPA Science Inventory

    As the surface in a permeable pavement system clogs and performance decreases, maintenance is required to preserve the design function. Currently, guidance is limited for scheduling maintenance on an as needed basis. Previous research has shown that surface clogging in a permea...

  6. Coal-tar-based pavement sealcoat, polycyclic aromatic Hydrocarbons (PAHs), and environmental health

    USGS Publications Warehouse

    Mahler, B.J.; Van Metre, P.C.

    2011-01-01

    Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat-the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots-as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large parts of the Nation. Several PAHs are suspected human carcinogens and are toxic to aquatic life.

  7. Reducing greenhouse gas emissions through strategic management of highway pavement roughness

    NASA Astrophysics Data System (ADS)

    Wang, Ting; Harvey, John; Kendall, Alissa

    2014-03-01

    On-road vehicle use is responsible for about a quarter of US annual greenhouse gas (GHG) emissions. Changes in vehicles, travel behavior and fuel are likely required to meet long-term climate change mitigation goals, but may require a long time horizon to deploy. This research examines a near-term opportunity: management of pavement network roughness. Maintenance and rehabilitation treatments can make pavements smoother and reduce vehicle rolling resistance. However, these treatments require material production and equipment operation, thus requiring a life cycle perspective for benefits analysis. They must also be considered in terms of their cost-effectiveness in comparison with other alternatives for affecting climate change. This letter describes a life cycle approach to assess changes in total GHG (measured in CO2-e) emissions from strategic management of highway pavement roughness. Roughness values for triggering treatments are developed to minimize GHG considering both treatment and use phase vehicle emission. With optimal triggering for GHG minimization, annualized reductions on the California state highway network over a 10-year analysis period are calculated to be 0.82, 0.57 and 1.38 million metric tons compared with historical trigger values, recently implemented values and no strategic intervention (reactive maintenance), respectively. Abatement costs calculated using /metric-ton CO2-e are higher than those reported for other transportation sector abatement measures, however, without considering all benefits associated with pavement smoothness, such as vehicle life and maintenance, or the time needed for deployment.

  8. Environmental Effects of Pervious Pavement as a Low Impact Development Installation in Urban Regions - Chapter 13

    EPA Science Inventory

    Pervious pavement systems can be used to reduce stormwater runoff volume and are efficient at removing solids from runoff; however, the pollutant removal efficiency for nutrients, metals, and organic contaminants is yet to be determined due to either a lack of data or inconsisten...

  9. Re-Evaluation of the AASHTO-Flexible Pavement Design Equation with Neural Network Modeling

    PubMed Central

    Tiğdemir, Mesut

    2014-01-01

    Here we establish that equivalent single-axle loads values can be estimated using artificial neural networks without the complex design equality of American Association of State Highway and Transportation Officials (AASHTO). More importantly, we find that the neural network model gives the coefficients to be able to obtain the actual load values using the AASHTO design values. Thus, those design traffic values that might result in deterioration can be better calculated using the neural networks model than with the AASHTO design equation. The artificial neural network method is used for this purpose. The existing AASHTO flexible pavement design equation does not currently predict the pavement performance of the strategic highway research program (Long Term Pavement Performance studies) test sections very accurately, and typically over-estimates the number of equivalent single axle loads needed to cause a measured loss of the present serviceability index. Here we aimed to demonstrate that the proposed neural network model can more accurately represent the loads values data, compared against the performance of the AASHTO formula. It is concluded that the neural network may be an appropriate tool for the development of databased-nonparametric models of pavement performance. PMID:25397962

  10. Beyond the Beaten Track: Resettlement Initiatives of Pavement Dwellers and Slum Dwellers in Bombay.

    ERIC Educational Resources Information Center

    Patel, Sheela

    1988-01-01

    The Society for Promotion of Adult Resource Centres was created to alleviate the problem of railway settlement families and pavement dwellers in Bombay, India. The area resource center provides information, analysis of available resources, discussion of problems, and sharing of experiences. (JOW)

  11. Arabidopsis FH1 Formin Affects Cotyledon Pavement Cell Shape by Modulating Cytoskeleton Dynamics.

    PubMed

    Rosero, Amparo; Oulehlová, Denisa; Stillerová, Lenka; Schiebertová, Petra; Grunt, Michal; Žárský, Viktor; Cvrčková, Fatima

    2016-03-01

    Plant cell morphogenesis involves concerted rearrangements of microtubules and actin microfilaments. We previously reported that FH1, the main Arabidopsis thaliana housekeeping Class I membrane-anchored formin, contributes to actin dynamics and microtubule stability in rhizodermis cells. Here we examine the effects of mutations affecting FH1 (At3g25500) on cell morphogenesis and above-ground organ development in seedlings, as well as on cytoskeletal organization and dynamics, using a combination of confocal and variable angle epifluorescence microscopy with a pharmacological approach. Homozygous fh1 mutants exhibited cotyledon epinasty and had larger cotyledon pavement cells with more pronounced lobes than the wild type. The pavement cell shape alterations were enhanced by expression of the fluorescent microtubule marker GFP-microtubule-associated protein 4 (MAP4). Mutant cotyledon pavement cells exhibited reduced density and increased stability of microfilament bundles, as well as enhanced dynamics of microtubules. Analogous results were also obtained upon treatments with the formin inhibitor SMIFH2 (small molecule inhibitor of formin homology 2 domains). Pavement cell shape in wild-type (wt) and fh1 plants in some situations exhibited a differential response towards anti-cytoskeletal drugs, especially the microtubule disruptor oryzalin. Our observations indicate that FH1 participates in the control of microtubule dynamics, possibly via its effects on actin, subsequently influencing cell morphogenesis and macroscopic organ development. PMID:26738547

  12. Internal hydrological mechanism of permeable pavement and interaction with subsurface water - slides

    EPA Science Inventory

    A permeable pavement site located at the Seitz Elementary School on Fort Riley, Kansas was selected for this study. An 80-space parking lot was built behind the school as part of an EPA ORD collaboration with the U.S. Army under the Net Zero program. The parking lot design includ...

  13. Internal hydrological mechanism of permeable pavement and interaction with subsurface water

    EPA Science Inventory

    Many communities are implementing green infrastructure stormwater control measures (SCMs) in urban environments across the U.S. to mimic pre-urban, natural hydrology more closely. Permeable pavement is one SCM infrastructure that has been commonly selected for both new and retro...

  14. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information... include: (i) A pavement condition analysis that includes ride, distress, rutting, and surface friction...

  15. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the..., distress, rutting, and surface friction (as appropriate); (iv) Traffic information including volumes and... include: (i) A pavement condition analysis that includes ride, distress, rutting, and surface friction...

  16. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information... include: (i) A pavement condition analysis that includes ride, distress, rutting, and surface friction...

  17. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... performed; (iii) Condition data that includes roughness, distress, rutting, and surface friction (as... analysis that includes roughness, distress, rutting, and surface friction (as appropriate); (ii) A pavement... life (performance and remaining service life to be developed with time); and (iii) An...

  18. Investigation of Primary Causes of Load-Related Cracking in Asphalt Concrete Pavement in North Carolina

    NASA Astrophysics Data System (ADS)

    Park, Hong Joon

    This dissertation presents causes of cracking in asphalt concrete pavement in North Carolina through field investigation and laboratory experiments with field extracted material. North Carolina is experiencing higher than anticipated rates of fatigue cracking compared to other state. These higher than expected rates could be reflective of the national trends in mix design practice or could be caused by structural pavement failures. The problems associated with premature cracking in North Carolina pavements point to the need to evaluate the North Carolina Department of Transportation (NCDOT) mixes, processes, and measures to ensure that these factors properly balance the goals of preventing cracking and minimizing permanent deformation. Without solid data from in-service pavements, any conclusions regarding the causes of these failures might be pure conjecture. Accordingly, this research examines material properties through laboratory experiments using field-extracted materials and investigates in situ pavements and pavement structure. In order to assess condition of existing pavement, alligator cracking index (ACI) was developed. The asphalt content in the top layer that exhibits top-down cracking or bottom-up cracking has a proportional relationship to ACI values. The air void content in a bottom layer that exhibits top-down cracking or bottom-up cracking shows an inverse proportional relationship to ACI values. These observations reflect reasonable results. A comparison between ACI and asphalt film thickness values does not produce noteworthy findings, but somewhat reasonable results are evident once the range of comparison is narrowed down. Thicker film thicknesses show higher ACI values. From field core visual observations, road widening is identified as a major cause of longitudinal cracking. Regions with observed layer interface separation tend to have low ACI values. Through tensile strain simulation based on actual field conditions, it is observed that

  19. Structural analyses of a rigid pavement overlaying a sub-surface void

    NASA Astrophysics Data System (ADS)

    Adam, Fatih Alperen

    Pavement failures are very hazardous for public safety and serviceability. These failures in pavements are mainly caused by subsurface voids, cracks, and undulation at the slab-base interface. On the other hand, current structural analysis procedures for rigid pavement assume that the slab-base interface is perfectly planar and no imperfections exist in the sub-surface soil. This assumption would be violated if severe erosion were to occur due to inadequate drainage, thermal movements, and/or mechanical loading. Until now, the effect of erosion was only considered in the faulting performance model, but not with regards to transverse cracking at the mid-slab edge. In this research, the bottom up fatigue cracking potential, caused by the combined effects of wheel loading and a localized imperfection in the form of a void below the mid-slab edge, is studied. A robust stress and surface deflection analysis was also conducted to evaluate the influence of a sub-surface void on layer moduli back-calculation. Rehabilitative measures were considered, which included a study on overlay and fill remediation. A series regression of equations was proposed that provides a relationship between void size, layer moduli stiffness, and the overlay thickness required to reduce the stress to its original pre-void level. The effect of the void on 3D pavement crack propagation was also studied under a single axle load. The amplifications to the stress intensity was shown to be high but could be mitigated substantially if stiff material is used to fill the void and impede crack growth. The pavement system was modeled using the commercial finite element modeling program Abaqus RTM. More than 10,000 runs were executed to do the following analysis: stress analysis of subsurface voids, E-moduli back-calculation of base layer, pavement damage calculations of Beaumont, TX, overlay thickness estimations, and mode I crack analysis. The results indicate that the stress and stress intensity are, on

  20. Multiple nuclide cosmogenic dating of very old desert pavements on the Puna Plateau, Northwest Argentina

    NASA Astrophysics Data System (ADS)

    Dortch, J.; Schoenbohm, L. M.

    2011-12-01

    Wind erosion of bedrock has been suggested to be responsible for the removal of more than 800 m of strata in the Qaidam Basin while wind deposition creates large-scale landforms such as the loess plateau. Wind eroded landforms, such as desert pavements in the Namibian Desert, Africa, form relic landscapes that are stable for more than 5 Ma. Desert pavements are of particular importance because of their widespread occurrence on terraces and fans, in mountains and coastal areas, and in hot and cold deserts including: Southwestern Africa, Antartic Dry valleys, Southwest USA, Denmark, Ireland, Israel, Sweden, and Central Tibet. Moreover, greater than 95 % of ventifacts on desert pavements are suspected to be late Quaternary to Holocene in age and are located on surfaces suitable for cosmogenic radionuclide dating. In spite of this, glacial, fluvial, and mass wasting systems have received far more attention than wind as an important geomorphic agent of erosion, deposition, and rock mass redistribution. Our goal is to: 1) quantify bedrock wind erosion rates; 2) quantify the ages of old, stable desert pavements; 3) and to identify which lithology-isotope pair provides the most accurate exposure ages for desert pavements in arid landscapes. The Puna Plateau, Argentina, is an ideal area to undertake this study because numerous wind eroded/deposited landforms are present, rates of fluvial erosion are low, and glaciation is limited. Mapping using remote sensed images shows that a significant portion of the Puna Plateau surface is covered by wind eroded or wind deposited landforms. These landforms align with the dominant wind direction (southeast) determined from ~450 ventifact measurements from 9 locations on the plateau. Twelve amalgamated samples sets that span six lithologies (granite, gneiss, quartzite, rhyolite, diabase, and basalt) using four cosmogenic isotopes (10Be, 26Al, 36Cl, 3He) on ventifacted clasts were collected from two surfaces to identify the most

  1. Orientation patterns of stone pavements as a result of modern geomorphologic processes

    NASA Astrophysics Data System (ADS)

    Dietze, Michael; Kleber, Arno

    2010-05-01

    Stone pavements are typical surface features of climate-sensitive, arid environments. They form a tightly interlocking mosaic of clasts, covering virtually stone-free aeolian material. However, this mosaic does not generally exhibit random orientation of its constituents. Rather, there are systematic unimodal to bimodal distributions of stone length axes present. These orientation patterns may be the result of active geomorphologic processes, implying the unstable and fragile nature of this landform as well as a dominant lateral geomorphologic component, not considered in existing models of stone pavement formation. Responsible processes should be controlled by relief properties and may thus be described by topographic attributes. From three study areas (Laguna Salada, Mexico, eastern Mojave Desert and southern Sevier Basin, USA) we present measurements of pavement stone orientations and their relationship to landscape parameters. From 1 by 1 m sized plots azimuthal digital images were taken, corrected, georeferenced and length as well as orientation angle of the a- and b-axes of at least 100 stones were digitised. Subsequently, statistical parameters of circular data were calculated. From a digital elevation model relief attributes were derived to test their influence on pavement patterns. Three general types of orientation patterns were identified from all study areas: unimodal, bimodal and unoriented. These types are clustered together and may change within small lateral distance. The type of pattern is not influenced by stone dimensions or the formation character of the site (i.e. basalt flow vs. alluvial fan). Relief properties (e.g. slope length, specific catchment, inclination), controlling lateral geomorphologic processes appear to play a major role in generating orientation patterns in stone pavement surfaces. Hence, from pattern analysis the dynamic nature of these features can be drawn.

  2. Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement

    USGS Publications Warehouse

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (ΣPAH8) in the 0.03-m samples above sealed lots (1320 ng m-3) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m-3). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m-3) was five times greater than above unsealed lots (26.0 ng m-3). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 μg m-2 h-1, respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces.

  3. Relation Between PAHs and Coal-Tar-Based Pavement Sealant in Urban Environments (Invited)

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; van Metre, P. C.

    2010-12-01

    Since 2003, coal-tar-based sealant products have come under increased scrutiny as a source of PAHs in urban environments. Sealant (or sealcoat) is the black, shiny substance often applied to asphalt pavement, in particular parking lots and driveways, for esthetic and maintenance purposes. Coal-tar-based sealant, one of the two primary pavement sealant types on the market, typically is 20-35 percent coal-tar pitch, a known carcinogen that is more than 50 percent polycyclic aromatic hydrocarbons (PAHs). The PAH content of the coal-tar-based sealant product is about 1,000 times that of a similar, asphalt-based product, on average. This difference is reflected in regional differences in sealant use and PAH concentrations in pavement dust. In the central and eastern U.S., where the coal-tar-based formulation is prevalent, ΣPAH in mobile particles from sealed pavement have been shown to be about 1,000 times higher than in the western U.S., where the asphalt-based formulation is prevalent (the median ΣPAH concentrations are 2,200 mg/kg in the central and eastern U.S. and 2.1 mg/kg in the western U.S.). Source apportionment modeling indicates that, in the central and eastern U.S., particles from sealed pavement are contributing the majority of the PAHs in recently deposited (post-1990) lake sediment, with implications for ecological health, and that coal-tar-based sealant is the primary cause of upward trends in PAHs in U.S. urban lakes. From the standpoint of human health, research indicates that mobile particles from parking lots with coal-tar-based sealant are tracked indoors, resulting in elevated PAH concentrations in house dust. Coal-tar-based sealcoat being applied to an asphalt parking lot at the University of Texas Pickle Research Center.

  4. Environmental history recorded in eolian deposits under stone pavements, eastern Mojave Desert, USA

    NASA Astrophysics Data System (ADS)

    Wells, Stephen; Fuchs, Markus; Dietze, Elisabeth; Lomax, Johanna; Kleber, Arno; Dietze, Michael

    2016-04-01

    Reconstructing the evolution of arid landscapes is challenged by the limited availability of appropriate environmental archives. A widespread surface feature of arid landscapes - stone pavement - traps eolian fines and can form an accretionary archive, growing with time and thereby recording essential information about the conditions under which it evolves. Based on a regional example in the eastern Mojave Desert, USA, seven stone pavement-covered soil-sediment sections on 560 and 270 ka old basalt flows are condensed to a correlation framework, comprising five distinct, successive sedimentological units. An OSL-based chronology enables correlation of this new sediment archive with other environmental archives from the region. Three of the stratigraphic units are of accretionary nature and the top of each unit is mantled by a new generation of stone pavement. These stratigraphic units were deposited between >32.3-20.4 ka, 20.4-16.5 ka and younger than 16.5 ka, appearing to be strongly coupled with the history of the nearby ancient Lake Mojave and enhancing our knowledge of the eolian activity in this area. End-member modelling analysis of sampled grain-size distributions allows identification of a local detritus component, four separate eolian components and two distinct clay enrichment components, contributing different quantities of sediment sources to the five stratigraphic units. These findings improve current concepts about the evolution of stone pavements and their role as conveyers of information about environmental conditions in arid landscapes. Stone pavement-covered accretionary sediment deposits are a new key archive that allows quantifying the relative importance of dust accretion, slope processes, soil formation and vegetation cover.

  5. Pavement Sealcoat, PAHs, and Water Quality of Urban Water Bodies: An Overview

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Van Metre, P. C.; Ingersoll, C.; Kunz, J. L.; Kienzler, A.; Devaux, A.; Bony, S.

    2014-12-01

    Coal-tar-based (CT) sealcoat is used to protect and beautify the asphalt pavement of driveways and parking lots primarily in the central, southern, and northeastern U.S. and in Canada. CT sealcoat typically is 20 to 35 percent crude coal tar or coal-tar pitch and contains from 50,000 to 100,000 mg/kg PAHs, about 1,000 times more than asphalt-based (AS) sealcoat or asphalt itself. Tires and snowplows abrade the friable sealcoat surface into fine particles—PAH concentrations in fine particles (dust) from CT-sealcoated pavement are about 1,000 times higher than in dust from AS-sealcoated pavement (median total PAH concentrations 2,200 and 2.1 mg/kg, respectively). Use of CT sealcoat has several implications for urban streams and lakes. Source apportionment modeling has indicated that, in regions where CT sealcoat is prevalent, particles from sealcoated pavement are contributing the majority of the PAHs to recently deposited lake sediment, with implications for ecological health. Acute 2-d toxicity of runoff from CT-sealcoated pavement to stream biota, demonstrated for a cladoceran (Ceriodaphnia dubia) and fathead minnows (Pimephales promelas), continues for samples collected as long as weeks or months following sealcoat application. Using the fish-liver cell line RGL-W1, runoff collected as much as 36 days following CT-sealcoat application has been demonstrated to cause DNA damage and impair DNA repair capacity. These results demonstrate that CT runoff is a potential hazard to aquatic ecosystems for at least several weeks after sealant application, and that exposure to sunlight can enhance toxicity and genetic damage. Recent research has provided direct evidence that restricting use of CT sealcoat in a watershed can lead to a substantial reduction in PAH concentrations in receiving water bodies.

  6. Implications of Use of Coal-Tar-Based Pavement Sealcoat on Urban Water Quality

    NASA Astrophysics Data System (ADS)

    Van Metre, P. C.

    2015-12-01

    Coal-tar-based (CT) sealcoat is used to protect and improve the appearance of asphalt pavement of driveways and parking lots primarily in the central and eastern U.S. and in Canada. CT sealcoat typically is 20 to 35% crude coal tar or coal-tar pitch and contains from 50,000 to 100,000 mg/kg polycyclic aromatic hydrocarbons (PAH), about 1,000 times more than asphalt-based (AS) sealcoat or asphalt itself. Tires and snowplows abrade the friable sealcoat surface into fine particles—median total PAH concentrations in dust from CT-sealcoated pavement are 2,200 mg/kg compared to a median concentration of 11 mg/kg for dust from unsealed pavement. Use of CT sealcoat has several implications for urban streams and lakes. Source apportionment modeling has indicated that, in regions where CT sealcoat is prevalent, particles from sealcoated pavement are contributing the majority of the PAHs to recently deposited lake sediment, often resulting in sediment concentrations above toxicity thresholds based on effects-based sediment quality guidelines. Acute 2-day laboratory toxicity testing of simulated runoff from CT-sealcoated pavement to a cladoceran (Ceriodaphnia dubia) and fathead minnows (Pimephales promelas) demonstrated that toxicity continues for samples collected for weeks or months following sealcoat application and that toxicity is enhanced by exposure to UV light. Using the fish-liver cell line RTL-W1, runoff collected as much as 36 days following CT-sealcoat application has been demonstrated to cause DNA damage and impair DNA repair capacity. These results demonstrate that CT runoff is a potential hazard to aquatic ecosystems and that exposure to sunlight can enhance toxicity and genetic damage. Recent research has provided direct evidence that restricting use of CT sealcoat in a watershed can lead to a substantial reduction in PAH concentrations in receiving water bodies.

  7. Composites

    NASA Astrophysics Data System (ADS)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-Nędza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  8. Implementation and Validation of the Viscoelastic Continuum Damage Theory for Asphalt Mixture and Pavement Analysis in Brazil

    NASA Astrophysics Data System (ADS)

    Nascimento, Luis Alberto Herrmann do

    This dissertation presents the implementation and validation of the viscoelastic continuum damage (VECD) model for asphalt mixture and pavement analysis in Brazil. It proposes a simulated damage-to-fatigue cracked area transfer function for the layered viscoelastic continuum damage (LVECD) program framework and defines the model framework's fatigue cracking prediction error for asphalt pavement reliability-based design solutions in Brazil. The research is divided into three main steps: (i) implementation of the simplified viscoelastic continuum damage (S-VECD) model in Brazil (Petrobras) for asphalt mixture characterization, (ii) validation of the LVECD model approach for pavement analysis based on field performance observations, and defining a local simulated damage-to-cracked area transfer function for the Fundao Project's pavement test sections in Rio de Janeiro, RJ, and (iii) validation of the Fundao project local transfer function to be used throughout Brazil for asphalt pavement fatigue cracking predictions, based on field performance observations of the National MEPDG Project's pavement test sections, thereby validating the proposed framework's prediction capability. For the first step, the S-VECD test protocol, which uses controlled-on-specimen strain mode-of-loading, was successfully implemented at the Petrobras and used to characterize Brazilian asphalt mixtures that are composed of a wide range of asphalt binders. This research verified that the S-VECD model coupled with the GR failure criterion is accurate for fatigue life predictions of Brazilian asphalt mixtures, even when very different asphalt binders are used. Also, the applicability of the load amplitude sweep (LAS) test for the fatigue characterization of the asphalt binders was checked, and the effects of different asphalt binders on the fatigue damage properties of the asphalt mixtures was investigated. The LAS test results, modeled according to VECD theory, presented a strong correlation with

  9. Effects of reclaimed asphalt pavement on indirect tensile strength test of foamed asphalt mix tested in dry condition

    NASA Astrophysics Data System (ADS)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    Indirect tensile strength (ITS) test was conducted to analyse strength of the foamed asphalt mixes incorporating reclaimed asphalt pavement. Samples were tested for ITS after cured in the oven at 40°C for 72 hours. This testing condition known as dry condition or unconditioned. Laboratory results show that reclaimed asphalt pavement (RAP) contents insignificantly affect the ITS results. ITS results significantly affected by foamed bitumen contents.

  10. Cathodoluminescence microscopy and petrographic image analysis of aggregates in concrete pavements affected by alkali-silica reaction

    SciTech Connect

    Stastna, A.; Sachlova, S.; Pertold, Z.; Prikryl, R.; Leichmann, J.

    2012-03-15

    Various microscopic techniques (cathodoluminescence, polarizing and electron microscopy) were combined with image analysis with the aim to determine a) the modal composition and degradation features within concrete, and b) the petrographic characteristics and the geological types (rocks, and their provenance) of the aggregates. Concrete samples were taken from five different portions of Highway Nos. D1, D11, and D5 (the Czech Republic). Coarse and fine aggregates were found to be primarily composed of volcanic, plutonic, metamorphic and sedimentary rocks, as well as of quartz and feldspar aggregates of variable origins. The alkali-silica reaction was observed to be the main degradation mechanism, based upon the presence of microcracks and alkali-silica gels in the concrete. Use of cathodoluminescence enabled the identification of the source materials of the quartz aggregates, based upon their CL characteristics (i.e., color, intensity, microfractures, deformation, and zoning), which is difficult to distinguish only employing polarizing and electron microscopy. - Highlights: Black-Right-Pointing-Pointer ASR in concrete pavements on the Highways Nos. D1, D5 and D11 (Czech Republic). Black-Right-Pointing-Pointer Cathodoluminescence was combined with various microscopic techniques and image analysis. Black-Right-Pointing-Pointer ASR was attributed to aggregates. Black-Right-Pointing-Pointer Source materials of aggregates were identified based on cathodoluminescence characteristics. Black-Right-Pointing-Pointer Quartz comes from different volcanic, plutonic and metamorphic parent rocks.

  11. Field Performance of Asphalt Pavements with New Technologies in Northern Nevada

    NASA Astrophysics Data System (ADS)

    Faeth, Benjamin Michael

    The Regional Transportation Commission (RTC) of the Washoe Valley Area has been tasked to determine if three advanced asphalt pavement technologies and one modified aggregate gradation are suitable for implementation within Reno, Stead, and Sparks Nevada. This was accomplished through research and test roads and Intersections to determine if Recycled Asphalt Pavement (RAP), Warm Mix Asphalt (WMA), Polymer-Modified Asphalt Binder, and the Type 2-R aggregate gradation were succeeding in their design plans. Over the course of several years the streets being used by RTC to test the technologies are succeeding within their design lifespans, and the Intersections being used to test the Type 2-R aggregate gradation are showing significant resistance to rutting. Due to the roads and Intersections not being more than 10 years old, these conclusions are subject to change over time.

  12. A review on using crumb rubber in reinforcement of asphalt pavement.

    PubMed

    Mashaan, Nuha Salim; Ali, Asim Hassan; Karim, Mohamed Rehan; Abdelaziz, Mahrez

    2014-01-01

    An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction. PMID:24688369

  13. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    SciTech Connect

    Handayani, Gunawan

    2015-04-16

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  14. A numerical model for flexible pavements rut depth evolution with time

    NASA Astrophysics Data System (ADS)

    Allou, Fatima; Chazallon, Cyrille; Hornych, Pierre

    2007-01-01

    A simplified method has been developed for the finite elements modelling of flexible pavements rut depth evolution with time. This method is based on the shakedown theory established by Zarka for metallic structures. The yield surface of Drucker-Prager and the plastic potential of Von Mises have been used. The simplified method determines straightforwardly the purely elastic state or the elastic shakedown state or the plastic shakedown state. The calibration of the simplified method with two unbound granular materials for roads under repeated loads triaxial tests, is explained. Then, a finite elements modelling of a flexible pavement has been carried out. Calculations of 2D and 3D have been performed and rut depth evolutions with time are shown, which underline the capabilities of the model to take into account the accumulation of plastic strains along the loading cycles. Copyright

  15. Recycling crumb rubber modified asphalt pavements (revised). Final research report, September 1992-August 1994

    SciTech Connect

    Crockford, W.W.; Makunike, D.; Davison, R.R.; Scullion, T.; Billiter, T.C.

    1995-07-01

    There has been concern that the legislative mandate to use waste rubber in paving applications will result in a severe environmental problem when it becomes necessary to recycle these pavements. If successful recycling is possible, the long term performance of these pavements becomes a concern. The results of this study indicate that it is possible to recycle this material. However, some techniques for conventional asphalt mixture design, material processing, and construction must be modified to ensure this success, and some techniques may not be appropriate when waste rubber is present in the mixture to be recycled. Many of the results presented in this study are based on experiences in Tyler and San Antonio, Texas, where two of the earliest crumb rubber recycling operations in the United States have transpired.

  16. Use of shredded tires in the subbase layer of asphalt pavements

    SciTech Connect

    Papp, W.J. Jr.; Maher, M.H.; Baker, R.F.

    1997-12-31

    Research was conducted on the use of shredded scrap tires for use in the subbase layer of asphalt pavements. Mixtures of shredded scrap tires with virgin soil provide a means of recycling unwanted tires and conserving a finite supply of virgin soil. The mechanistic procedure for the design of pavement systems requires resilient modulus values. Plastic and elastic strains were measured using external LVDT`s and internal proximity sensors. Resilient modulus measurements were conducted on cohesionless soils mixed with various amounts of shredded tire chips. The performance f the shredded tire mixture is compared to that of the naturally occurring virgin soil used in subbase applications in New Jersey. A number of experimental issues are discussed such as: method of compaction, optimum ratio of shredded tire chips to soil, optimum size and gradation of shredded tire chips, and strength testing using California Bearing Ratio.

  17. A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement

    PubMed Central

    Mashaan, Nuha Salim; Ali, Asim Hassan; Karim, Mohamed Rehan; Abdelaziz, Mahrez

    2014-01-01

    An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction. PMID:24688369

  18. The Efficiency Analysis of Low Impact Development Applied in Taiwan: A Case Study of Porous Pavement

    NASA Astrophysics Data System (ADS)

    Huang, Y. H.; Liu, H. J.; Hsu, N. S.; Chang, F. M.

    2014-12-01

    Low Impact Development (LID) has been developed since the end of 1990s. Lots of successful experience based on this new technology have been made. Taiwan Executive Yuan is conducting a six-year (2014~2019) program "Integrated River Basin Management Plan" applying LID to build sponge cities. Construction and Planning Agency, Ministry of the Interior is editing the manual of LID technology for Taiwan. However, since the hydrological environments, physiographic conditions, climates, the strength and frequency of disasters in Taiwan are different from that in America, this study takes the first laboratory experiment and model simulation to evaluate the efficiency of application of LID in Taiwan.LID Facilities includes porous pavement, rain garden, green roof, tree box filter facilities and so on, and in this study, porous pavement is taken as an example for discussion. In the part of laboratory experiments, the sand box experiments is designed to operate with the specified rainfall return period calculated by Horton formula and rainfall characteristics of Taipei. Then the outflow hydrograph in each designed rainfall of specified return period can be evaluated. As for model simulation, this study constructs LID simulation elements by SWMM model and tests the suitability for simulation of the outflow hydrograph obtained from experiments, and definitely quantifies the efficiency of water retention and flood reduction of porous pavement. The results fits well with the experimental observation data with less than 10% error of pick flow. It suggests that, with LID simulation elements constructed in this study, the efficiency of LID in actual on-site application can be evaluated.The results shows that porous pavement is able to delay arrival time of pick about 5% ~10% and reduce the pick flow about 5%~20%, and hold the ability of near 3~5% water retention. It proves that application of LID can retain water and reduce flood in Taiwan.

  19. Recent advances in the evaluation of the strength and deformation properties of flexible pavements using GPR

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; Bianchini Ciampoli, Luca; Benedetto, Andrea; Alani, Amir M.; Loizos, Andreas; D'Amico, Fabrizio

    2016-04-01

    Even though there is plenty of literature contributions related to the non-destructive evaluation of road pavements using ground-penetrating radar (GPR), with several purposes spanning from the layer thicknesses evaluation to the detection of highly wet spots in the subsurface, there is still a lack of highly-reliable results concerning the mechanical assessment of road pavements, by using this technology. This work endeavours to face this topic and proposes a semi-empirical model for predicting the elastic modulus of a flexible pavement, by employing GPR. Data were collected over three different road sections within the districts of Madrid and Guadalajara, Spain. In particular, GPR surveys were carried out at the speed of traffic over the roads N320 and N211 in the district of Gadalajara and the road N320 in the district of Madrid, for a total of 39 kilometers, approximately. In particular, air-coupled radar systems with a 1000 MHz center frequency antenna and two different 2000 MHz center frequency antennas, mounted onto an instrumented vehicle, were here employed. The calibration of the model was then performed by exploiting ground-truth data coming from other non-destructive technologies. In more details, an instrumented lorry equipped with a curviameter, namely, a deflection tool capable to collect and process continuously and in real time the mechanical response of the flexible pavement, was used in the above road sections. Promising results are here presented, and the potential of GPR for monitoring the mechanical performances of a road network is also proved. Acknowledgement The Authors thank COST, for funding the Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar."

  20. Evaluation of a highway pavement using non destructive tests: Falling Weight Deflectometer and Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Marecos, Vania; Fontul, Simona; de Lurdes Antunes, Maria

    2015-04-01

    This paper presents the results of the application of Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) to assess the bearing capacity of a rehabilitated flexible highway pavement that began to show the occurrence of cracks in the surface layer, about one year after the improvement works. A visual inspection of the surface of the pavement was performed to identify and characterize the cracks. Several core drills were done to analyse the cracks propagation in depth, these cores were also used for GPR data calibration. From the visual inspection it was concluded that the development of the cracks were top-down and that the cracks were located predominantly in the wheel paths. To determine the thickness of the bituminous and granular layers GPR tests were carried out using two horn antennas of 1,0 GHz and 1,8 GHz and a radar control unit SIR-20, both from GSSI. FWD load tests were performed on the wheel paths and structural models were established, based on the deflections measured, through back calculation. The deformation modulus of the layers was calculated and the bearing capacity of the pavement was determined. Summing up, within this study the GPR was used to continuously detect the layer thickness and the GPR survey data was calibrated with core drills. The results showed variations in the bituminous layer thickness in comparison to project data. From the load tests it was concluded that the deformation modulus of the bituminous layers were also vary variable. Limitations on the pavement bearing capacity were detected in the areas with the lower deformation modulus. This abstract is of interest for COST Action TU1208 Civil Engineering Applications of Ground Penetrating Radar.

  1. Laser Scanning on Road Pavements: A New Approach for Characterizing Surface Texture

    PubMed Central

    Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

    2012-01-01

    The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the “texture” appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey. PMID:23012535

  2. A Hessian-based methodology for automatic surface crack detection and classification from pavement images

    NASA Astrophysics Data System (ADS)

    Ghanta, Sindhu; Shahini Shamsabadi, Salar; Dy, Jennifer; Wang, Ming; Birken, Ralf

    2015-04-01

    Around 3,000,000 million vehicle miles are annually traveled utilizing the US transportation systems alone. In addition to the road traffic safety, maintaining the road infrastructure in a sound condition promotes a more productive and competitive economy. Due to the significant amounts of financial and human resources required to detect surface cracks by visual inspection, detection of these surface defects are often delayed resulting in deferred maintenance operations. This paper introduces an automatic system for acquisition, detection, classification, and evaluation of pavement surface cracks by unsupervised analysis of images collected from a camera mounted on the rear of a moving vehicle. A Hessian-based multi-scale filter has been utilized to detect ridges in these images at various scales. Post-processing on the extracted features has been implemented to produce statistics of length, width, and area covered by cracks, which are crucial for roadway agencies to assess pavement quality. This process has been realized on three sets of roads with different pavement conditions in the city of Brockton, MA. A ground truth dataset labeled manually is made available to evaluate this algorithm and results rendered more than 90% segmentation accuracy demonstrating the feasibility of employing this approach at a larger scale.

  3. Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design

    NASA Astrophysics Data System (ADS)

    Solanki, Pranshoo

    Pavements are vulnerable to subgrade layer performance because it acts as a foundation. Due to increase in the truck traffic, pavement engineers are challenged to build more strong and long-lasting pavements. To increase the load-bearing capacity of pavements, subgrade layer is often stabilized with cementitious additives. Thus, an overall characterization of stabilized subgrade layer is important for enhanced short- and long-term pavement performance. In this study, the effect of type and amount of additive on the short-term performance in terms of material properties recommended by the new Mechanistic-Empirical Pavement Design Guide (MEPDG) is examined. A total of four soils commonly encountered as subgrades in Oklahoma are utilized. Results show that the changes in the Mr, ME and UCS values stabilized specimens depend on the soil type and properties of additives. The long-term performance (or durability) of stabilized soil specimens is investigated by conducting freeze-thaw (F-T) cycling, vacuum saturation and tube suction tests on 7-day cured P-, K- and C-soil specimens stabilized with 6% lime, 10% CFA and 10% CKD. This study is motivated by the fact that during the service life of pavement stabilized layers are subjected to F-T cycles and moisture variations. It is found that that UCS value of all the stabilized specimens decreased with increase in the number of F-T cycles. A strong correlation was observed between UCS values retained after vacuum saturation and F-T cycles indicating that vacuum saturation could be used as a time-efficient and inexpensive method for evaluating durability of stabilized soils. In this study, short- and long-term observations from stabilization of sulfate bearing soil with locally available low (CFA), moderate (CKD) and high (lime) calcium-based stabilizers are determined to evaluate and compare the effect of additive type on the phenomenon of sulfate-induced heave. The impact of different factors on the development of the

  4. Automated real-time pavement distress detection using fuzzy logic and neural network

    NASA Astrophysics Data System (ADS)

    Cheng, Heng-Da

    1996-11-01

    Conventional visual and manual pavement distress analysis approaches are very costly, time-consuming, dangerous, labor-intensive, tedious, subjective, having high degree of variability, unable to provide meaningful quantitative information, and almost always leading to inconsistencies in distress detail over space and across evaluations. In this paper, a novel system for multipurpose automated real-time pavement distress analysis based on fuzzy logic and neural networks will be studied. The proposed system can: provide high data acquisition rates; effectively and accurately identify the type, severity and extent of surface distress; improve the safety and efficiency of data collection; offer an objective standard of analysis and classification of distress; help identify cost effective maintenance and repair plans; provide images and examples through information highway to other user/researchers; provide image/sample back for training or as the benchmark for testing new algorithms. The proposed system will reduce the cost for maintenance/repair greatly, and can contribute to other research in pavement maintenance, repair and rehabilitation.

  5. Laser scanning on road pavements: a new approach for characterizing surface texture.

    PubMed

    Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

    2012-01-01

    The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the "texture" appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey. PMID:23012535

  6. Temporal evolution modeling of hydraulic and water quality performance of permeable pavements

    NASA Astrophysics Data System (ADS)

    Huang, Jian; He, Jianxun; Valeo, Caterina; Chu, Angus

    2016-02-01

    A mathematical model for predicting hydraulic and water quality performance in both the short- and long-term is proposed based on field measurements for three types of permeable pavements: porous asphalt (PA), porous concrete (PC), and permeable inter-locking concrete pavers (PICP). The model was applied to three field-scale test sites in Calgary, Alberta, Canada. The model performance was assessed in terms of hydraulic parameters including time to peak, peak flow and water balance and a water quality variable (the removal rate of total suspended solids). A total of 20 simulated storm events were used for model calibration and verification processes. The proposed model can simulate the outflow hydrographs with a coefficient of determination (R2) ranging from 0.762 to 0.907, and normalized root-mean-square deviation (NRMSD) ranging from 13.78% to 17.83%. Comparison of the time to peak flow, peak flow, runoff volume and TSS removal rates between the measured and modeled values in model verification phase had a maximum difference of 11%. The results demonstrate that the proposed model is capable of capturing the temporal dynamics of the pavement performance. Therefore, the model has great potential as a practical modeling tool for permeable pavement design and performance assessment.

  7. Utilize Cementitious High Carbon Fly Ash (CHCFA) to Stabilize Cold In-Place Recycled (CIR) Asphalt Pavement as Base Coarse

    SciTech Connect

    Wen, Haifang; Li, Xiaojun; Edil, Tuncer; O'Donnell, Jonathan; Danda, Swapna

    2011-02-05

    The purpose of this study was to evaluate the performance of cementitious high carbon fly ash (CHCFA) stabilized recycled asphalt pavement as a base course material in a real world setting. Three test road cells were built at MnROAD facility in Minnesota. These cells have the same asphalt surface layers, subbases, and subgrades, but three different base courses: conventional crushed aggregates, untreated recycled pavement materials (RPM), and CHCFA stabilized RPM materials. During and after the construction of the three cells, laboratory and field tests were carried out to characterize the material properties. The test results were used in the mechanistic-empirical pavement design guide (MEPDG) to predict the pavement performance. Based on the performance prediction, the life cycle analyses of cost, energy consumption, and greenhouse gasses were performed. The leaching impacts of these three types of base materials were compared. The laboratory and field tests showed that fly ash stabilized RPM had higher modulus than crushed aggregate and RPM did. Based on the MEPDG performance prediction, the service life of the Cell 79 containing fly ash stabilized RPM, is 23.5 years, which is about twice the service life (11 years) of the Cell 77 with RPM base, and about three times the service life (7.5 years) of the Cell 78 with crushed aggregate base. The life cycle analysis indicated that the usage of the fly ash stabilized RPM as the base of the flexible pavement can significantly reduce the life cycle cost, the energy consumption, the greenhouse gases emission. Concentrations of many trace elements, particularly those with relatively low water quality standards, diminish over time as water flows through the pavement profile. For many elements, concentrations below US water drinking water quality standards are attained at the bottom of the pavement profile within 2-4 pore volumes of flow.

  8. Coal-Tar-Based Pavement Sealcoat and PAHs: Implications for the Environment, Human Health, and Stormwater Management

    PubMed Central

    2012-01-01

    Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20−35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments—including stormwater runoff, lake sediment, soil, house dust, and most recently, air—contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them. PMID:22296333

  9. Methane and carbon monoxide emissions from asphalt pavement: Measurements and estimates of their important to global budgets

    SciTech Connect

    Tyler, S.C.; Dlugokencky, E.; Zimmerman, P.R.; Cicerone, R.J. ); Lowe, D.C. )

    1990-08-20

    The authors measured emissions of methane from asphalt surfaces used in pavement for roadways. Maximum emissions were 22 mg/m{sup 2}/hr for 1- to 4-week-old pavement during maximum sunlight intensity. Emissions were much smaller at low sunlight intensity and dropped off to negligible amounts at night. Smaller emissions were observed for asphalt pavement of 2.5 to 3 years approximate age under similar conditions. Comparison measurements of carbon monoxide emissions resulted in maximum emissions of about 2.6 mg/m{sup 2}hr for 1-week-old pavement. These findings indicate that emissions of CH{sub 4} and CO are a function of both sunlight and temperature. Based on these results, methane emissions from asphalt pavement cannot be a significant source of atmospheric methane as compared to other identified methane sources. Therefore, although asphalt methane emissions are a form of fossil fuel methane, they cannot explain the relatively high fraction of {sup 14}C-depleted methane in the atmosphere.

  10. Coal-tar-based pavement sealcoat and PAHs: implications for the environment, human health, and stormwater management

    USGS Publications Warehouse

    Mahler, Barbara J.; Van Metre, Peter C.; Crane, Judy L.; Watts, Alison W.; Scoggins, Mateo; Williams, E. Spencer

    2012-01-01

    Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20-35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments—including stormwater runoff, lake sediment, soil, house dust, and most recently, air—contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them.

  11. MaNIAC-UAV - a methodology for automatic pavement defects detection using images obtained by Unmanned Aerial Vehicles

    NASA Astrophysics Data System (ADS)

    Henrique Castelo Branco, Luiz; César Lima Segantine, Paulo

    2015-09-01

    Intelligent Transportation Systems - ITS is a set of integrated technologies (Remote Sensing, Image Processing, Communications Systems and others) that aim to offer services and advanced traffic management for the several transportation modes (road, air and rail). Collect data on the characteristics and conditions of the road surface and keep them update is an important and difficult task that needs to be currently managed in order to reduce accidents and vehicle maintenance costs. Nowadays several roads and highways are paved, but usually there is insufficient updated data about current condition and status. There are different types of pavement defects on the roads and to keep them in good condition they should be constantly monitored and maintained according to pavement management strategy. This paper presents a methodology to obtain, automatically, information about the conditions of the highway asphalt pavement. Data collection was done through remote sensing using an UAV (Unmanned Aerial Vehicle) and the image processing and pattern recognition techniques through Geographic Information System.

  12. Global Cooling: Policies to Cool the World and Offset Global Warming from CO2 Using Reflective Roofs and Pavements

    SciTech Connect

    Akbari, Hashem; Levinson, Ronnen; Rosenfeld, Arthur; Elliot, Matthew

    2009-08-28

    Increasing the solar reflectance of the urban surface reduce its solar heat gain, lowers its temperatures, and decreases its outflow of thermal infrared radiation into the atmosphere. This process of 'negative radiative forcing' can help counter the effects of global warming. In addition, cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings; and cool roofs and cool pavements mitigate summer urban heat islands, improving outdoor air quality and comfort. Installing cool roofs and cool pavements in cities worldwide is a compelling win-win-win activity that can be undertaken immediately, outside of international negotiations to cap CO{sub 2} emissions. We propose an international campaign to use solar reflective materials when roofs and pavements are built or resurfaced in temperate and tropical regions.

  13. Waxing and waning of dreissenid pavements as a possible result of astronomical forcing

    NASA Astrophysics Data System (ADS)

    Harzhauser, Mathias; Mandic, Oleg; Kern, Andrea K.; Piller, Werner E.; Neubauer, Thomas A.; Albrecht, Christian; Wilke, Tom

    2014-05-01

    Human induced range expansions of invasive dreissenid bivalves are of great concern. However, the underlying biological processes are only poorly understood, partly due to the lack of information on natural expansion events. Here we use the extinct bivalve species Sinucongeria primiformis as a model organism for testing natural (i.e. pre-Anthropocene) blooms of dreissenid species in a lacustrine system of Lake Pannon during the Tortonian (~10.5 Myr; Late Miocene). 600 samples from a consecutive core were evaluated for the relative abundance of this pavement-forming mollusc, which cover about 8 millennia of Late Miocene time with a decadal resolution. The formation of these pavements occurred in repetitive cycles, which were also documented for carious other geophysical and geochemical and biotic proxies. The investigated bivalve was among the most successful species settling in offshore environments of Lake Pannon, where it formed vast pavements. The tolerance for poorly oxygenated lake bottoms close to the epilimnion/hypolimnion boundary was probably the key adaptation to outcompete other species in this lacustrine offshore environment. We document that solar forcing might have played an important role for lake hydrology, which in turn allowed population blooms during phases of improved ecological conditions. The repeated establishment of dysoxic conditions was lethal for the populations and is reflected by pyrite incrustations in the shell cavities. The cyclicities might be expressions of the Gleissberg cycles and the 500 yr cycle, indicating that bottom water oxygenation was strongly influenced by these solar cycles. This example shows that dreissenid bivalves may be pioneers, which quickly dominate aquatic ecosystems even in pre-Anthropocene records. The surprisingly strong influence of solar forcing on the success of the Miocene dreissenids is an overlooked aspect for predicting the population dynamics of extant dreissenids. This study was supported by the

  14. Fiber Bragg grating sensors for use in pavement structural strain-temperature monitoring

    NASA Astrophysics Data System (ADS)

    Wang, Jian-Neng; Tang, Jaw-Luen; Chang, Hsiang-Ping

    2006-03-01

    In this paper, we describe the development and realization of a newly high-resolution temperature and strain sensor with fiber Bragg grating (FBG) technology. The FBG sensor consists of a reference fiber grating and a grating pair scheme that could offer the potential of simultaneous measurement of strain and temperature for monitoring pavement structures. Experimental results showed that measurement errors of 6 μɛ and 0.13 °C for strain and temperature could be achieved, respectively. The reliability and long-term stability for temperature measurement with this type of sensor were examined by mounting sensors on the surface of asphalt and concrete specimens. Small root mean square temperature variations (better than 1 °C) and excellent long-term stability (within 2%) were obtained. The maximum variations in temperature for 48 hours were only 1.94% and 2.32% for asphalt and concrete specimens, respectively. The feasibility of strain measurement for pavement structures was conducted by mounting the packaged sensor on the surface of an asphalt specimen under the indirect tensile loading condition. The measured strains from the packaged FBG sensor agreed linearly with applied loads. A finite-element model (FEM) was conducted to verify the strains obtained from the sensors. In comparison with experimental data and numerical results, the numerical values were all located within FBG measurement error ranges. The strain differences between measurements from the FBG sensor and FEM predictions were between 5% and 7%. This type of simple and low-cost FBG sensor is expected to benefit the developments and applications of pavement structures or transportation infrastructure.

  15. Pavement evaluation and management system for Rhode Island. Phase 1: Feasibility and implementation recommendations. Volume 1: Summary findings

    NASA Astrophysics Data System (ADS)

    Carmichael, R. F., III; Hudson, W. R.

    1982-09-01

    The feasibility and implementation for pavement evaluation and management (PEMS) for the Rhode Island Department of Transportation (RIDOT) are presented. A process is outlined whereby network level PEMS activities can be adequately implemented in the future. Cost and time estimates are presented considering the current manpower, cost, and time constraints particular to RIDOT. Recommendations are made concerning the four primary areas of pavement evaluation measurements; visual condition surveys, deflection measurements, roughness measurements, and skid resistance measurements. Recommendations are also made concerning the collection of additional related data such as traffic.

  16. Thermal conductance of and heat generation in tire-pavement interface and effect on aircraft braking

    NASA Technical Reports Server (NTRS)

    Miller, C. D.

    1976-01-01

    A finite-difference analysis was performed on temperature records obtained from a free rolling automotive tire and from pavement surface. A high thermal contact conductance between tire and asphalt was found on a statistical basis. Average slip due to squirming between tire and asphalt was about 1.5 mm. Consequent friction heat was estimated as 64 percent of total power absorbed by bias-ply, belted tire. Extrapolation of results to aircraft tire indicates potential braking improvement by even moderate increase of heat absorbing capacity of runway surface.

  17. Passive pavement-mounted acoustical linguistic drive alert system and method

    DOEpatents

    Kisner, Roger A.; Anderson, Richard L.; Carnal, Charles L.; Hylton, James O.; Stevens, Samuel S.

    2001-01-01

    Systems and methods are described for passive pavement-mounted acoustical alert of the occupants of a vehicle. A method of notifying a vehicle occupant includes providing a driving medium upon which a vehicle is to be driven; and texturing a portion of the driving medium such that the textured portion interacts with the vehicle to produce audible signals, the textured portion pattern such that a linguistic message is encoded into the audible signals. The systems and methods provide advantages because information can be conveyed to the occupants of the vehicle based on the location of the vehicle relative to the textured surface.

  18. Recycled asphalt pavement as a base and sub-base material

    SciTech Connect

    Maher, M.H.; Gucunski, N.; Papp, W.J. Jr.

    1997-12-31

    Laboratory and field investigations were conducted to evaluate the use of recycled asphalt pavement (RAP) in roadway base and sub-base applications. The laboratory resilient modulus test results showed RAP has comparable strength with dense graded aggregate base and sub-base material used in the state of New Jersey. Using the spectral-analysis-of-the-surface-waves method (SASW), the field testing program evaluated the elastic modulus of the RAP base in the field and verified the laboratory results. The field test results showed higher modulus and stiffness for RAP than the dense graded aggregate base normally used in state of New Jersey.

  19. Use of stabilized bottom ash for bound layers of road pavements.

    PubMed

    Toraldo, Emanuele; Saponaro, Sabrina; Careghini, Alessandro; Mariani, Edoardo

    2013-05-30

    This paper reports about the lab scale results obtained by using stabilized bottom ash (SBA) from an Italian municipal solid waste incinerator as aggregates in cement-bound mixes and asphalt concretes for road pavements. The investigation focused on SBA content. From the road construction point of view, performance related to compaction, volumetric and mechanical properties were assessed. The environmental aspects were investigated performing leaching tests. The results suggested that SBA satisfied the environmental Italian law for reuse of non-hazardous waste but affected significantly the stress-strain behavior of the final products. Therefore a maximum percentage of 10% was suggested. PMID:23535513

  20. STUDY ON PROPERTIES OF SKID RESISTANCE ON FREEZING PAVEMENTS AND QUANTITATIVE EVALUATION METHOD OF ANTIFREEZING EFFECTS

    NASA Astrophysics Data System (ADS)

    Tanaka, Shunsuke; Takeichi, Kiyoshi; Masuyama, Yukiei; Takahashi, Naoto

    Snow and ice control in winter roads trends to be controlled by the skid friction coefficients in North America and North European countries at present, but the measurements are not necessarily easy. We studied on a simplified measurement method based on the relationship between skid friction coefficients and the bare pavement ratio (BPR) in the laboratory tests and field tests. The factors of BPR, surface textures and antifreezing materials which affect the skid friction coefficient are reviewed by a multiple linear regression analysis and a spectrum analysis, considering different freezing surfaces. These studies indicate that conclusions induced by laboratory tests could be applied to roads in service.

  1. Respirable crystalline silica exposures during asphalt pavement milling at eleven highway construction sites.

    PubMed

    Hammond, Duane R; Shulman, Stanley A; Echt, Alan S

    2016-07-01

    Asphalt pavement milling machines use a rotating cutter drum to remove the deteriorated road surface for recycling. The removal of the road surface has the potential to release respirable crystalline silica, to which workers can be exposed. This article describes an evaluation of respirable crystalline silica exposures to the operator and ground worker from two different half-lane and larger asphalt pavement milling machines that had ventilation dust controls and water-sprays designed and installed by the manufacturers. Manufacturer A completed milling for 11 days at 4 highway construction sites in Wisconsin, and Manufacturer B completed milling for 10 days at 7 highway construction sites in Indiana. To evaluate the dust controls, full-shift personal breathing zone air samples were collected from an operator and ground worker during the course of normal employee work activities of asphalt pavement milling at 11 different sites. Forty-two personal breathing zone air samples were collected over 21 days (sampling on an operator and ground worker each day). All samples were below 50 µg/m(3) for respirable crystalline silica, the National Institute for Occupational Safety and Health recommended exposure limit. The geometric mean personal breathing zone air sample was 6.2 µg/m(3) for the operator and 6.1 µg/m(3) for the ground worker for the Manufacturer A milling machine. The geometric mean personal breathing zone air sample was 4.2 µg/m(3) for the operator and 9.0 µg/m(3) for the ground worker for the Manufacturer B milling machine. In addition, upper 95% confidence limits for the mean exposure for each occupation were well below 50 µg/m(3) for both studies. The silica content in the bulk asphalt material being milled ranged from 7-23% silica for roads milled by Manufacturer A and from 5-12% silica for roads milled by Manufacturer B. The results indicate that engineering controls consisting of ventilation controls in combination with water-sprays are

  2. The synergy of permeable pavements and geothermal heat pumps for stormwater treatment and reuse.

    PubMed

    Tota-Maharaj, K; Scholz, M; Ahmed, T; French, C; Pagaling, E

    2010-12-14

    The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff. PMID:21275249

  3. Strain transfer analysis of optical fiber based sensors embedded in an asphalt pavement structure

    NASA Astrophysics Data System (ADS)

    Wang, Huaping; Xiang, Ping

    2016-07-01

    Asphalt pavement is vulnerable to random damage, such as cracking and rutting, which can be proactively identified by distributed optical fiber sensing technology. However, due to the material nature of optical fibers, a bare fiber is apt to be damaged during the construction process of pavements. Thus, a protective layer is needed for this application. Unfortunately, part of the strain of the host material is absorbed by the protective layer when transferring the strain to the sensing fiber. To account for the strain transfer error, in this paper a theoretical analysis of the strain transfer of a three-layered general model has been carried out by introducing Goodman’s hypothesis to describe the interfacial shear stress relationship. The model considers the viscoelastic behavior of the host material and protective layer. The effects of one crack in the host material and the sensing length on strain transfer relationship are been discussed. To validate the effectiveness of the strain transfer analysis, a flexible asphalt-mastic packaged distributed optical fiber sensor was designed and tested in a laboratory environment to monitor the distributed strain and appearance of cracks in an asphalt concrete beam at two different temperatures. The experimental results indicated that the developed strain transfer formula can significantly reduce the strain transfer error, and that the asphalt-mastic packaged optical fiber sensor can successfully monitor the distributed strain and identify local cracks.

  4. Development of Paving Material for Footpath and CAR Park Pavement Using Granite Soil

    NASA Astrophysics Data System (ADS)

    Nagamachi, Masaharu; Mizuguchi, Hiroyuki; Inoue, Kentaro; Kamada, Koichi

    It is required to develop new paving materials for pavements, such as footpaths, car parks, etc., in parks, having good landscape. Such paving materials have been already developed, but these do not have sufficient strength, abrasion resistance and frost resistance. In this study, a new paving was examined material using cement, sand and granite soil. The mix proportion of this material tested was 2:4:4 of cement, sand and granite soil by mass. The maximum flexural and compressive strength were both obtained at a water content of 14% of the total mass, and the strength were several times larger than that of paving material on the market consisting of 10% of cement and 90% granite soil. The abrasion resistance was tested according to ASTM C 779, and this resistance was about four times greater than that of the paving material on the market. The frost resistance was obtained high value compared with the concrete of 72% in water cement ratio by a new simple resisting test method for freezing and thawing using liquid nitrogen and warm water. It is considered that this new paving material is applicable to pavement for footpath, car park, etc.

  5. Assessment of an action against environmental noise: Acoustic durability of a pavement surface with crumb rubber.

    PubMed

    Vázquez, V F; Luong, J; Bueno, M; Terán, F; Paje, S E

    2016-01-15

    Environmental noise is a worldwide problem that has an adverse effect in the quality of life of urban population. Some work has shown that there is a correlation between environmental noise and health issues as sleep disturbance or annoyance. This study presents the time evolution of a test track fabricated with an asphalt mixture with 20% of crumb rubber by weight of bitumen, added by the wet process. A complete surface characterization has been performed by determining tire/pavement sound levels, road texture profiles, in-situ dynamic stiffness and sound absorption of compacted and extracted sample cores. Two measurement campaigns were performed: just after mixture laying and after 3 years in service. This study confirms that the use of crumb rubber as a modifier of bituminous binders (CRMB) can improve the pavement characteristics: gap-graded mixtures with crumb rubber can be used in the action plans as urban rehabilitation measure to fight noise pollution. However, this noise reduction seems to decrease with age at a rate of approximately 0.15 dB(A) per year. PMID:26519582

  6. Pavement crack detection combining non-negative feature with fast LoG in complex scene

    NASA Astrophysics Data System (ADS)

    Wang, Wanli; Zhang, Xiuhua; Hong, Hanyu

    2015-12-01

    Pavement crack detection is affected by much interference in the realistic situation, such as the shadow, road sign, oil stain, salt and pepper noise etc. Due to these unfavorable factors, the exist crack detection methods are difficult to distinguish the crack from background correctly. How to extract crack information effectively is the key problem to the road crack detection system. To solve this problem, a novel method for pavement crack detection based on combining non-negative feature with fast LoG is proposed. The two key novelties and benefits of this new approach are that 1) using image pixel gray value compensation to acquisit uniform image, and 2) combining non-negative feature with fast LoG to extract crack information. The image preprocessing results demonstrate that the method is indeed able to homogenize the crack image with more accurately compared to existing methods. A large number of experimental results demonstrate the proposed approach can detect the crack regions more correctly compared with traditional methods.

  7. Feasibility of using 100% Recycled Asphalt Pavement mixtures for road construction

    NASA Astrophysics Data System (ADS)

    Carlson, Russell Edgar, IV

    Recycled Asphalt Pavement (RAP) is the largest recycled good in the United States and 80 million tons are recycled yearly, saving taxpayers about $1.5 billion dollars. This paper explores the possibility of utilizing 100% RAP materials in asphalt pavement. Asphalt mixtures are produced at 135°C in a typical asphalt plant. However, at 135°C, not all binder from RAP materials may not become effective for coating aggregates. The main objective of the study is to determine the amount of effective binder available from RAP in the asphalt plant. The 100% RAP mixes have aged binder that can alter mix designs and interaction with virgin binder. In this study, to determine low temperature cracking resistance and fatigue performance, samples were prepared using a 100% RAP mix with no virgin binder and a 100% RAP mix with virgin asphalt binder to achieve the optimum binder content of the mix. Second, to determine the effectiveness of binder from RAP materials, compaction tests were performed by heating RAP materials at various temperatures. It was found that 100% RAP mixes cannot be feasible for field use if additional virgin binder is added to reach the optimum asphalt content. Based on limited test results, the low temperature grade was not within proper limits but the beam fatigue testing results were acceptable. Based on compaction test results, additional heating is needed to increase the effectiveness of asphalt binder from RAP materials.

  8. Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement

    USGS Publications Warehouse

    Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

    2012-01-01

    Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10–4, as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10–5. Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0–6 years of age).

  9. Performance of an enhanced pervious pavement system loaded with large volumes of hydrocarbons.

    PubMed

    Newman, Alan P; Puehmeier, Tim; Shuttleworth, Andy; Pratt, Christopher J

    2014-01-01

    Five litres of lubricating oil and two 8.5 litre batches of diesel were deposited on each of two hydraulically isolated experimental enhanced pervious pavement parking bays. The 50 mm aggregate subbases of the two bays were of either recycled concrete or crushed limestone. The bays were constructed in such a way that a near-surface gravity separator was created by the arranging of the outlet pipes such that a permanent pool of water was maintained in the system and water could only enter from below the level of any floating oil. Dissolved/dispersed hydrocarbons were measured at acceptable concentrations when monitoring was carried out over a period of approximately 5 months. The maximum concentration was 7.2 mg/l and of all the samples collected only 3% exceeded the 5 mg/l limit applied in the UK for a class 1 interceptor, and the majority of samples had hydrocarbon concentrations of less than 2 mg/l. Much more significant is the fact that no free product was discharged from either system up to the time the experiment was dismantled 2 years from the first oil application despite the fact that sufficient hydrocarbon had been added to each pavement to produce a film on a water surface of over 500 hectares. PMID:25225930

  10. Relationships between laboratory measured HMA material and mixture properties and pavement performance at WesTrack

    NASA Astrophysics Data System (ADS)

    Hand, Adam J. T.

    For years researchers and practitioners alike in the pavements and materials industry have attempted to establish relationships between laboratory measured material and mixture properties and actual pavement performance. The ultimate goal of any highway agency is to have performance related specifications, which require such relationships. This sounds simple enough, but in reality such a task is not so simple due to the extremely complex behavior of hot mix asphalt. Due to the fact that it takes many years to evaluate new materials and methodologies, the use of accelerated loading facilities such as WesTrack for evaluation purposes becomes very advantageous. The research presented here produces multiple permanent deformation performance relationships for the WesTrack project, some of which may be extended to other environments. An attempt to develop similar fatigue performance relationships was unsuccessful due partially to the lack of fatigue distress at WesTrack to date. Additionally, mix design and some quality control data summaries are presented for the project along with an investigation into a potential cause of the premature rutting of coarse Superpave mixes. The investigation resulted in the development of precision statements for the ASTM D5821-95 coarse aggregate angularity test method and a better understanding of the sensitivity of coarse Superpave mixtures.

  11. Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas.

    PubMed

    Mahler, Barbara J; Ingersoll, Christopher G; Van Metre, Peter C; Kunz, James L; Little, Edward E

    2015-04-21

    Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ≤10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application. PMID:25860716

  12. Electrical resistance tomography for monitoring the infiltration of water into a pavement section

    SciTech Connect

    Buettner, M.; Daily, B.; Ramirez, A.

    1997-07-03

    Electrical resistance tomography (ERT) was used to follow the infiltration of water into pavement section at the UC Berkeley Richmond Field Station. A volume of pavement 1m square and 1.29 m deep was sampled by an ERT array consisting of electrodes in 9 drilled holes plus 8 surface electrodes. The data were collected using a computer controlled data acquisition system capable of collecting a full data set in under 1 hour, allowing for nearly real time sampling of the infiltration. The infiltration was conducted in two phases. During the first phase, water was introduced into the asphalt-concrete (AC) layers at a slow rate of about 8 ml per hour for a period of about 6 days. In the second phase, water was introduced into the asphalt-treated-permeable base (ATPB) layer at a more rapid rate of about 100 ml/h for about 2 days. The ERT images show that water introduced into the upper AC layers shows up as a decrease in resistivity which grows with time. The images also appear to show that when water moves into the layers below the ATPB, the resistivity increases; an unexpected result. There are some indications that the water moved laterally as well as down into the deeper ATPB and the aggregate base. The images also show that when water is introduced directly into the ATPB and aggregate layer, the water moves into the the underlying materials much more quickly.

  13. Assessment of the aging level of rejuvenated hot mixed asphalt concrete pavements

    NASA Astrophysics Data System (ADS)

    McGovern, Megan; Buttlar, William G.; Reis, Henrique

    2016-04-01

    The efficacy of asphalt rejuvenator on restoring the properties of oxidatively aged asphalt was tested via a non-collinear ultrasonic subsurface wave mixing technique modified for field use. Longitudinal transducers were mounted on angle wedges to generate subsurface dilatational waves to allow for pavement evaluation when there is only access to one side. Because in the field the asphalt concrete (AC) pavement properties (i.e., ultrasonic velocities and attenuations) are unknown, a pre-determined fixed incident angle (based on the AC mixture type) was used, which allows for practical implementation in the field. Oxidative aged AC specimens were coated with rejuvenator (10% by weight of the binder) and left to dwell for varying amounts of time. Once the dwell time reached the desired amount, the specimen was immediately ultrasonically tested. The frequency ratio, f2/f1, at which the interaction took place and the normalized nonlinear wave generation parameter, β/β0, were recorded and compared against a reference plot. It was observed that the rejuvenator had the effect of restoring the nonlinear properties to those corresponding to a virgin sample after a sufficient amount of dwell time. The ability of the rejuvenator to fully penetrate and act on the binder was observed to be dependent on the porosity and aggregate structure, and thus varied for each specimen. As a result, some portions of the binder were restored to a greater extent than others. This non-uniform nature was captured via the nonlinear ultrasonic technique.

  14. Energy harvesting from pavements via PVDF: hybrid piezo-pyroelectric effects

    NASA Astrophysics Data System (ADS)

    Tao, Junliang; Hu, Jie; Wu, Guangxi

    2016-04-01

    In the U.S., there are over 4 million miles (6 million km) of roadways and more than 250 million registered vehicles. The energy lost in the pavement system due to traffic-induced vibration and deformation is enormous. If effectively harvested, such energy can serve as an alternative sustainable energy source that can be easily integrated to the transportation system. The potential of PVDF, which is a piezoelectric polymer material, is investigated as a potential energy harvester integrated in pavement systems. The uniqueness of this study lies in that the electrical response of PVDF under coupled mechanical and thermal stimulations are studied. It is well known that most piezoelectric materials are also pyroelectric materials, which convert temperature change into electricity. However, the potential of PVDF as a hybrid piezo-pyroelectric energy harvester has been seldom studied. Through series of well controlled experiments, it is found that there exists interesting coupling phenomenon between piezoelectric and pyroelectric effects of PVDF: the voltage generated by simultaneous mechanical and thermal stimulations is the sum of voltages generated by separate stimulations. In addition, an estimation of power generation through piezoelectric and pyroelectric effect is conducted. Finally, the overall effects of temperature on hybrid piezo-pyroelectric energy harvesting are discussed.

  15. Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas

    USGS Publications Warehouse

    Mahler, Barbara J.; Ingersoll, Christopher G.; Van Metre, Peter C.; Kunz, James L.; Little, Edward E.

    2015-01-01

    Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ≤10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application.

  16. Water quality and quantity assessment of pervious pavements performance in experimental car park areas.

    PubMed

    Sañudo-Fontaneda, Luis A; Charlesworth, Susanne M; Castro-Fresno, Daniel; Andres-Valeri, Valerio C A; Rodriguez-Hernandez, Jorge

    2014-01-01

    Pervious pavements have become one of the most used sustainable urban drainage system (SUDS) techniques in car parks. This research paper presents the results of monitoring water quality from several experimental car park areas designed and constructed in Spain with bays made of interlocking concrete block pavement, porous asphalt, polymer-modified porous concrete and reinforced grass with plastic and concrete cells. Moreover, two different sub-base materials were used (limestone aggregates and basic oxygen furnace slag). This study therefore encompasses the majority of the materials used as permeable surfaces and sub-base layers all over the world. Effluent from the test bays was monitored for dissolved oxygen, pH, electric conductivity, total suspended solids, turbidity and total petroleum hydrocarbons in order to analyze the behaviour shown by each combination of surface and sub-base materials. In addition, permeability tests were undertaken in all car parks using the 'Laboratorio Caminos Santander' permeameter and the Cantabrian Portable Infiltrometer. All results are presented together with the influence of surface and sub-base materials on water quality indicators using bivariate correlation statistical analysis at a confidence level of 95%. The polymer-modified porous concrete surface course in combination with limestone aggregate sub-base presented the best performance. PMID:24718346

  17. Fast simulated annealing inversion of surface waves on pavement using phase-velocity spectra

    USGS Publications Warehouse

    Ryden, N.; Park, C.B.

    2006-01-01

    The conventional inversion of surface waves depends on modal identification of measured dispersion curves, which can be ambiguous. It is possible to avoid mode-number identification and extraction by inverting the complete phase-velocity spectrum obtained from a multichannel record. We use the fast simulated annealing (FSA) global search algorithm to minimize the difference between the measured phase-velocity spectrum and that calculated from a theoretical layer model, including the field setup geometry. Results show that this algorithm can help one avoid getting trapped in local minima while searching for the best-matching layer model. The entire procedure is demonstrated on synthetic and field data for asphalt pavement. The viscoelastic properties of the top asphalt layer are taken into account, and the inverted asphalt stiffness as a function of frequency compares well with laboratory tests on core samples. The thickness and shear-wave velocity of the deeper embedded layers are resolved within 10% deviation from those values measured separately during pavement construction. The proposed method may be equally applicable to normal soil site investigation and in the field of ultrasonic testing of materials. ?? 2006 Society of Exploration Geophysicists.

  18. Seismic monitoring of roadbeds for traffic flow, vehicle characterization, and pavement deterioration

    SciTech Connect

    Elbring, G.J.; Ormesher, R.C.; Holcomb, D.J.

    1998-01-01

    A road-side seismic monitoring system has been developed that includes not only instrumentation and fielding methods, but also data analysis methods and codes. The system can be used as either a passive or active monitoring system. In the passive mode, seismic signals generated by passing vehicles are recorded. Analysis of these signals provides information on the location, speed, length, and weight of the vehicle. In the active mode, designed for monitoring pavement degradation, a vibrating magnetostrictive source is coupled to the shoulder of the road and signals generated are recorded on the opposite side of the road. Analysis of the variation in surface wave velocity at various frequencies (dispersion) is used in an attempt to develop models of the near-surface pavement velocity structure. The monitoring system was tested at two sites in New Mexico, an older two-lane road and a newly-paved section of interstate highway. At the older site, the system was able to determine information about vehicle velocity, wheel-base length and weight. The sites showed significant differences in response and the results indicate the need for further development of the method to extract the most information possible for each site investigated.

  19. Hydrologic and Pollutant Removal Performance of a Full-Scale, Fully Functional Permeable Pavement Parking Lot - paper

    EPA Science Inventory

    To meet the need for long-term, full-scale, replicated studies of permeable pavement systems used in their intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditions, and maintenance regimes to evaluate these systems, the EPA’s Urb...

  20. Noise abatement and traffic safety: The trade-off of quieter engines and pavements on vehicle detection.

    PubMed

    Mendonça, C; Freitas, E; Ferreira, J P; Raimundo, I D; Santos, J A

    2013-03-01

    Road traffic sounds are a major source of noise pollution in urban areas. But recent developments such as low noise pavements and hybrid/electric engine vehicles cast an optimistic outlook over such an environmental problem. However, it can be argued that engine, tire, and road noise could be relevant sources of information to avoid road traffic conflicts and accidents. In this paper, we analyze the potential trade-offs of traffic-noise abatement approaches in an experimental study, focusing for the first time on the impact and interaction of relevant factors such as pavement type, vehicle type, listener's age, and background noise, on vehicle detection levels. Results reveal that vehicle and pavement type significantly affect vehicle detection. Age is a significant factor, as both younger and older people exhibit lower detection levels of incoming vehicles. Low noise pavements combined with all-electric and hybrid vehicles might pose a severe threat to the safety of vulnerable road users. All factors interact simultaneously, and vehicle detection is best predicted by the loudness signal-to-noise ratio. PMID:23182778

  1. Three Permeable Pavements Performances for Priority Metal Pollutants and Metals associated with Deicing Chemicals from Edison Parking Lot, NJ - abstract

    EPA Science Inventory

    The U.S. Environmental Protection Agency constructed a 4000-m2 parking lot in Edison, New Jersey in 2009. The parking lot is surfaced with three permeable pavements [permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA)]. Samples of each p...

  2. Three Permeable Pavements Performances for Priority Metal Pollutants and Metals Associated with Deicing Chemicals from Edison Parking Lot, NJ

    EPA Science Inventory

    The U.S. Environmental Protection Agency constructed a 4000-m2 parking lot in Edison, New Jersey in 2009. The parking lot is surfaced with three permeable pavements [permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA)]. Samples of each p...

  3. Performance of a movable flexible pipe-encapsulated FBG sensor developed for shape monitoring of multi-layered pavement structure

    NASA Astrophysics Data System (ADS)

    Wang, Huaping; Liu, Wanqiu; Zhou, Zhi

    2014-03-01

    The large span and heterogeneous components of multi-layered pavement structure usually bring about stochastic damage, and many modern approaches, such as ground penetrating radar, integral imaging and optical fiber sensing technology, have been employed to detect the degeneration mechanism. Restricted by the cost and universality, novel elements for pavement monitoring are in high demand. Optical fiber sensing technology for high sensitivity, long stability, anti-corrosion and resistance to water erosion then is considered. Therefore, a movable FBG sensor located in flexible pipe is developed, which has long stroke inside inner wall of the hollow pipe, and a full-scale shape of the structure could be sketched just with one FBG. Theoretical and experimental methods about establishing the relationship between wavelength variable and curvature have been provided, and function about reconfiguring the coordinate is converted to a mathematic question. Move over, transfer error modification has been taken into account for modify related error. Multi-layered pavement model embedded with this sensor will be accomplished to inspect its performance in later work. The work in the paper affords a feasible method for shape monitoring and would be potentially valuable for the maintenance and inverse design of pavement structure.

  4. Reducing Conflicts between Motor Vehicles and Pedestrians: The Separate and Combined Effects of Pavement Markings and a Sign Prompt

    ERIC Educational Resources Information Center

    Huybers, Sherry; Van Houten, Ron; Malenfant, J.E. Louis

    2004-01-01

    The effects of a symbolic "yield here to pedestrians" sign and advance yield pavement markings on pedestrian/motor vehicle conflicts, motorists' yielding behavior, and the distance motorists' yield in advance of crosswalks were evaluated at multilane crosswalks at uncontrolled T intersections. In Experiment 1, the sign, when used alone, reduced…

  5. Measurements of the Stiffness and Thickness of the Pavement Asphalt Layer Using the Enhanced Resonance Search Method

    PubMed Central

    Zakaria, Nur Mustakiza; Yusoff, Nur Izzi Md.; Hardwiyono, Sentot; Mohd Nayan, Khairul Anuar

    2014-01-01

    Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard. PMID:25276854

  6. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and azaarenes in runoff from coal-tar- and asphalt-sealcoated pavement

    USGS Publications Warehouse

    Mahler, Barbara J.; Van Metre, Peter C.; Foreman, William T.

    2014-01-01

    Coal-tar-based sealcoat, used extensively on parking lots and driveways in North America, is a potent source of PAHs. We investigated how concentrations and assemblages of PAHs and azaarenes in runoff from pavement newly sealed with coal-tar-based (CT) or asphalt-based (AS) sealcoat changed over time. Samples of simulated runoff were collected from pavement 5 h to 111 d following application of AS or CT sealcoat. Concentrations of the sum of 16 PAHs (median concentrations of 328 and 35 μg/L for CT and AS runoff, respectively) in runoff varied relatively little, but rapid decreases in concentrations of azaarenes and low molecular weight PAHs were offset by increases in high molecular weight PAHs. The results demonstrate that runoff from CT-sealcoated pavement, in particular, continues to contain elevated concentrations of PAHs long after a 24-h curing time, with implications for the fate, transport, and ecotoxicological effects of contaminants in runoff from CT-sealcoated pavement.

  7. Rubber modified and performance based asphalt binder pavements: I-5 Nisqually River to Gravelly Lake. Post construction report

    SciTech Connect

    Pierce, L.M.

    1996-01-01

    The report describes the construction of asphalt pavements made with three types of asphalt binders. The three types of binders were PBA-6, PBA-6GR (ground rubber), and AR4000W. The two modified binders, PBA-6 and PBA-6GR, are being evaluated to determine their resistance to rutting as compared to the conventional binder, AR4000W.

  8. Use of leaching tests to quantify trace element release from waste to energy bottom ash amended pavements.

    PubMed

    Roessler, Justin G; Townsend, Timothy G; Ferraro, Christopher C

    2015-12-30

    A series of roadway tests strips were paved on-site at a landfill in Florida, U.S. Waste to energy (WTE) bottom ash was used as a partial course aggregate replacement in a hot mix asphalt (HMA) and a Portland cement concrete (PCC) pavement, along with control HMA and PCC sections. This allowed for a comparison of the relative degree of leaching between both materials (HMA and PCC) as well as between the ash-amended and control pavements. Batch and monolithic tank leaching tests were conducted on the pavements. Testing of the PCC samples demonstrated that Mo and Al were elevated above regulatory thresholds for both the control and ash amended samples. Further leach testing demonstrated that the release of Mo was likely from the PCC and not a result of the inclusion of the BA into pavement. Batch leach testing of ash-amended HMA samples revealed Sb as a constituent of potential concern. The results of the monolith leaching test displayed leaching of Sb within the same order of magnitude as the regulatory threshold. Calculation of the leachability index (LI) for Sb found that it would have limited mobility when incorporated in the HMA matrix. PMID:26340550

  9. 23 CFR Appendix to Subpart F of... - Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking Materials Appendix to Subpart F of Part 655 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRAFFIC OPERATIONS Traffic Control Devices on...

  10. Exposure to wear particles generated from studded tires and pavement induces inflammatory cytokine release from human macrophages.

    PubMed

    Lindbom, John; Gustafsson, Mats; Blomqvist, Göran; Dahl, Andreas; Gudmundsson, Anders; Swietlicki, Erik; Ljungman, Anders G

    2006-04-01

    Health risks associated with exposure to airborne particulate matter (PM) have been shown epidemiologically as well as experimentally, pointing to both respiratory and cardiovascular effects. Lately, wear particles generated from traffic have been recognized to be a major contributing source to the overall particle load, especially in the Nordic countries were studded tires are used. In this work, we investigated the inflammatory effect of PM10 generated from the wear of studded tires on two different types of pavement. As comparison, we also investigated PM10 from a traffic-intensive street, a subway station, and diesel exhaust particles (DEP). Human monocyte-derived macrophages, nasal epithelial cells (RPMI 2650), and bronchial epithelial cells (BEAS-2B) were exposed to the different types of particles, and the secretion of IL-6, IL-8, IL-10, and TNF-alpha into the culture medium was measured. The results show a significant release of cytokines from macrophages after exposure for all types of particles. When particles generated from asphalt/granite pavement were compared to asphalt/quartzite pavement, the granite pavement had a significantly higher capacity to induce the release of cytokines. The granite pavement particles induced cytokine release at the same magnitude as the street particles did, which was higher than what particles from both a subway station and DEP did. Exposure of epithelial cells to PM10 resulted in a significant increase of TNF-alpha secreted from BEAS-2B cells for all types of particles used (DEP was not tested), and the highest levels were induced by subway particles. None of the particle types were able to evoke detectable cytokine release from RPMI 2650 cells. The results indicate that PM10 generated by the wear of studded tires on the street surface is a large contributor to the cytokine-releasing ability of particles in traffic-intensive areas and that the type of pavement used is important for the level of this contribution

  11. PAH volatilization following application of coal-tar-based pavement sealant

    NASA Astrophysics Data System (ADS)

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-05-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2-3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (˜1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  12. GPR Image and Signal Processing for Pavement and Road Monitoring on Android Smartphones and Tablets

    NASA Astrophysics Data System (ADS)

    Benedetto, Francesco; Benedetto, Andrea; Tedeschi, Antonio

    2014-05-01

    Ground Penetrating Radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation and detects the reflected signals from subsurface structures. It can detect objects, changes in material, and voids and cracks. GPR has many applications in a number of fields. In the field of civil engineering one of the most advanced technologies used for road pavement monitoring is based on the deployment of advanced GPR systems. One of the most relevant causes of road pavement damage is often referable to water intrusion in structural layers. In this context, GPR has been recently proposed as a method to estimate moisture content in a porous medium without preventive calibration. Hence, the development of methods to obtain an estimate of the moisture content is a crucial research field involving economic, social and strategic aspects in road safety for a great number of public and private Agencies. In particular, a recent new approach was proposed to estimate moisture content in a porous medium basing on the theory of Rayleigh scattering, showing a shift of the frequency peak of the GPR spectrum towards lower frequencies as the moisture content increases in the soil. Addressing some of these issues, this work proposes a mobile application, for smartphones and tablets, for GPR image and signal processing. Our application has been designed for the Android mobile operating system, since it is open source and android mobile platforms are selling the most smartphones in the world (2013). The GPR map can be displayed in black/white or color and the user can zoom and navigate into the image. The map can be loaded in two different ways: from the local memory of the portable device or from a remote server. This latter possibility can be very useful for real-time and mobile monitoring of road and pavement inspection. In addition, the application allows analyzing the GPR data also in the frequency domain. It is

  13. PAH volatilization following application of coal-tar-based pavement sealant

    USGS Publications Warehouse

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  14. Numerical analysis of road pavement thermal deformability, based on Biot viscoelastic model of porous medium

    NASA Astrophysics Data System (ADS)

    Bartlewska-Urban, Monika; Zombroń, Marek; Strzelecki, Tomasz

    2016-03-01

    The following study presents numerical calculations for establishing the impact of temperature changes on the process of distortion of bi-phase medium represented using Biot consolidation equations with Kelvin-Voigt rheological skeleton presented, on the example of thermo-consolidation of a pavement of expressway S17. We analyzed the behavior of the expressway under the action of its own weight, dynamic load caused by traffic and temperature gradient. This paper presents the application of the Biot consolidation model with the Kelvin-Voigt skeleton rheological characteristics and the influence of temperature on the deformation process is taken into account. A three-dimensional model of the medium was created describing the thermal consolidation of a porous medium. The 3D geometrical model of the area under investigation was based on data obtained from the land surveying and soil investigation of a 200 m long section of the expressway and its shoulders.

  15. Research on a Novel Low Modulus OFBG Strain Sensor for Pavement Monitoring

    PubMed Central

    Wang, Chuan; Hu, Qingli; Lu, Qiyu

    2012-01-01

    Because of the fatigue and deflection damage of asphalt pavement, it is very important for researchers to monitor the strain response of asphalt layers in service under vehicle loads, so in this paper a novel polypropylene based OFBG (Optical Fiber Bragg Gratings) strain sensor with low modulus and large strain sensing scale was designed and fabricated. PP with MA-G-PP is used to package OFBG. The fabrication techniques, the physical properties and the sensing properties were tested. The experimental results show that this kind of new OFBG strain sensor is a wonderful sensor with low modulus (about 1 GPa) and good sensitivity, which would meet the needs for monitoring some low modulus materials or structures. PMID:23112584

  16. Coal-tar pavement sealants might substantially increase children's PAH exposures

    USGS Publications Warehouse

    Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

    2012-01-01

    Dietary ingestion has been identified repeatedly as the primary route of human exposure to polycyclic aromatic hydrocarbons (PAHs), seven of which are classified as probable human carcinogens (B2 PAHs) by the U.S. EPA. Humans are exposed to PAHs through ingestion of cooked and uncooked foods, incidental ingestion of soil and dust, inhalation of ambient air, and absorption through skin. Although PAH sources are ubiquitous in the environment, one recently identified PAH source stands out: Coal-tar-based pavement sealant—a product applied to many parking lots, driveways, and even playgrounds primarily in the central, southern, and eastern U.S.—has PAH concentrations 100–1000 times greater than most other PAH sources. It was reported recently that PAH concentrations in house dust in residences adjacent to parking lots with coal-tar-based sealant were 25 times higher than in residences adjacent to unsealed asphalt parking lots.

  17. A road pavement full-scale test track containing stabilized bottom ashes.

    PubMed

    Toraldo, E; Saponaro, S

    2015-01-01

    This paper reports the results of a road pavement full-scale test track built by using stabilized bottom ash (SBA) from an Italian municipal solid waste incinerator as the aggregate in granular foundation, cement-bound mixes and asphalt concretes. The investigation focused on both the performance and the environmental compatibility of such mixes, especially with regard to the effects of mixing, laying and compaction. From the road construction point of view, the performance related to the effects of mixing, laying and compaction on constructability was assessed, as well as the volumetric and the mechanical properties. Environmental aspects were investigated by leaching tests. The results suggested that SBA meets the environmental Italian law for the reuse of non-hazardous waste and could be used as road material with the procedures, plants and equipment currently used for road construction. PMID:25354811

  18. Study on Preserving Public Security of Installing 22 kV Distribution Equipment on Pavements

    NASA Astrophysics Data System (ADS)

    Murata, Koichi; Oka, Keisuke; Uemura, Satoshi; Ariga, Yasuo

    To cope with restructuring of electricity market, application of 22kV distribution systems to areas with high load density, is promising. To expand them, it is important to install 22kV distribution equipment on pavements and lots without fences. On the other hand, the neutral grounding method is expected for the 22kV distribution equipment in terms of rationalization of insulation. In this case, one line-to-ground fault current will be large. Therefore, to make safety of people, it is essential to decrease the contact voltage. In this paper, we will perform the simulation of current distribution in the case of one line-to-ground fault and study the security of human from the viewpoint of both step voltage and contact voltage. We will also clarify that we can lower the contact voltage by grounding mutually insulated inner box and outer box separately. Then we will propose the improved grounding method.

  19. Hypolithic Microbial Community of Quartz Pavement in the High-Altitude Tundra of Central Tibet

    PubMed Central

    Wong, Fiona K. Y.; Lacap, Donnabella C.; Lau, Maggie C. Y.; Aitchison, J. C.; Cowan, Donald A.

    2010-01-01

    The hypolithic microbial community associated with quartz pavement at a high-altitude tundra location in central Tibet is described. A small-scale ecological survey indicated that 36% of quartz rocks were colonized. Community profiling using terminal restriction fragment length polymorphism revealed no significant difference in community structure among a number of colonized rocks. Real-time quantitative PCR and phylogenetic analysis of environmental phylotypes obtained from clone libraries were used to elucidate community structure across all domains. The hypolithon was dominated by cyanobacterial phylotypes (73%) with relatively low frequencies of other bacterial phylotypes, largely represented by the chloroflexi, actinobacteria, and bacteriodetes. Unidentified crenarchaeal phylotypes accounted for 4% of recoverable phylotypes, while algae, fungi, and mosses were indicated by a small fraction of recoverable phylotypes. Electronic supplementary material The online version of this article (doi:10.1007/s00248-010-9653-2) contains supplementary material, which is available to authorized users. PMID:20336290

  20. Criteria for asphalt-rubber concrete in civil airport pavements: Mixture design

    NASA Astrophysics Data System (ADS)

    Roberts, F. L.; Lytton, R. L.; Hoyt, D.

    1986-07-01

    A mixture design procedure is developed to allow the use of asphalt-rubber binders in concrete for flexible airport pavement. The asphalt-rubber is produced by reacting asphalt with ground, scrap tire rubber to produce the binder for the asphalt-rubber concrete. Procedures for laboratory preparation of alsphalt-rubber binders using an equipment setup that was found by researchers to produce laboratory binders with similar properties to field processes are included. The rubber-asphalt concrete mixture design procedure includes adjustments to the aggregate gradation to permit space for the rubber particles in the asphalt-rubber binder as well as suggested mixing and compaction temperatures, and compaction efforts. While the procedure was used in the laboratory to successfully produce asphalt-rubber concrete mixtures, it should be evaluated in the field to ensure that consistent results can be achieved in a production environment.

  1. Rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems in the presence of trees.

    PubMed

    Scholz, Miklas; Uzomah, Vincent C

    2013-08-01

    The retrofitting of sustainable drainage systems (SuDS) such as permeable pavements is currently undertaken ad hoc using expert experience supported by minimal guidance based predominantly on hard engineering variables. There is a lack of practical decision support tools useful for a rapid assessment of the potential of ecosystem services when retrofitting permeable pavements in urban areas that either feature existing trees or should be planted with trees in the near future. Thus the aim of this paper is to develop an innovative rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems close to trees. This unique tool proposes the retrofitting of permeable pavements that obtained the highest ecosystem service score for a specific urban site enhanced by the presence of trees. This approach is based on a novel ecosystem service philosophy adapted to permeable pavements rather than on traditional engineering judgement associated with variables based on quick community and environment assessments. For an example case study area such as Greater Manchester, which was dominated by Sycamore and Common Lime, a comparison with the traditional approach of determining community and environment variables indicates that permeable pavements are generally a preferred SuDS option. Permeable pavements combined with urban trees received relatively high scores, because of their great potential impact in terms of water and air quality improvement, and flood control, respectively. The outcomes of this paper are likely to lead to more combined permeable pavement and tree systems in the urban landscape, which are beneficial for humans and the environment. PMID:23697848

  2. Pavement Subsidence in the Cumberland Gap Tunnel, USA: A Story of Groundwater Chemistry

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Currens, J. C.; Webb, S. E.; Rister, B. W.

    2014-12-01

    Cumberland Gap Tunnel was constructed in 1996 to improve highway travel between southeastern Kentucky and northeastern Tennessee and to restore Cumberland Gap to its historical appearance. About five years after construction, the concrete pavement in the tunnel began to exhibit noticeable signs of subsidence. Ground penetrating radar surveys detected voids in many areas of the limestone roadbed aggregate beneath the pavement. Field investigations conducted by the Kentucky Geological Survey and Kentucky Transportation Center from 2006 to 2008 discovered that groundwater was flowing from the bedrock invert into the aggregate along many parts of the tunnel. Average groundwater discharge from the tunnel was measured at approximately 1700 m3/d. We analyzed 265 groundwater samples collected from aggregate in different parts of the tunnel roadbed during low and high flow conditions. Calculated calcite saturation indices indicated that the groundwater was geochemically aggressive and capable of continuously dissolving calcite in the limestone aggregate although pH values of these water samples were near neutral. We also conducted an in-situ dissolution experiment by placing eight baskets filled with limestone aggregate beneath the roadbed in different locations in the tunnel for 178 days. At the end of the experiment, the limestone aggregate in contact with groundwater exhibited visual signs of dissolution and lost mass, and the highest mass loss recorded was 3.4 percent. Mass loss calculations based on kinetic models of calcite mineral and water samples taken near the baskets matched well with the actual measured mass losses, confirming that dissolution of calcite by the groundwater was the primary cause of the roadbed subsidence problem. Based on these findings, we suggested the limestone aggregate be replaced with noncarbonate (granite) aggregate to mitigate future road subsidence. The suggestion was adopted, and the repair was completed in early 2014.

  3. Permeability measurement and scan imaging to assess clogging of pervious concrete pavements in parking lots.

    PubMed

    Kayhanian, Masoud; Anderson, Dane; Harvey, John T; Jones, David; Muhunthan, Balasingam

    2012-03-01

    This paper describes a study that used permeability measurement along with physical and hydrological characteristics of 20 pervious concrete pavements in parking lots throughout California. The permeability was measured at five locations: the main entrance, an area with no traffic, and three separate measurements within a parking space at each parking lot. Hydrological and physical site characteristics such as traffic flow, erosion, vegetation cover, sediments accumulation, maintenance practice, presence of cracking, rainfall, and temperature data were also collected for each parking lot. These data were used to perform detailed statistical analysis to determine factors influencing changes in permeability and hence assessing possible cause of clogging. In addition, seven representative core samples were obtained from four different parking lots with permeability ranging from very low to very high. Porosity profiles produced from CT scanning were used to assess the possible nature and extent of clogging. Results showed that there is a large variation in permeability within each parking lot and between different parking lots. In general, the age of the parking lot is the predominant factor influencing the permeability. Statistical analysis revealed that fine sediment (particles less than 38 μm) mass is also an important influencing factor. Other influencing factors with lower significance included number of days with a temperature greater than 30°C and the amount of vegetation next to the parking lot. The combined scanned image analysis and porosity profile of the cores showed that most clogging occurs near the surface of the pavement. While lower porosity generally appeared to be limited to the upper 25 mm, in some core samples evidence of lower porosity was found up to 100mm below the surface. PMID:22115516

  4. Development of an evaporation-optimized and water-permeable pavement

    NASA Astrophysics Data System (ADS)

    Starke, P.; Göbel, P.; Coldewey, W. G.

    2009-04-01

    During recent decades, urban areas have been threatened more frequently by flood events. Furthermore, the potential for damage from these events has increased on average. The construction of houses, streets and parking lots has caused this trend by sealing the ground surface, i.e. these water-impermeable areas reduce the natural infiltration and evaporation-rates, and in some cases it is even completely stopped. The consequence is the so called "urban water cycle". Water from precipitation cannot be stored anywhere and so there is an immediate and very high surface run-off effect. Especially after intense rain events, canalisations and sewage-treatment plants are overloaded and this leads to higher costs for water treatment and to environmental damage. A practical solution to this problem is the use of water-permeable pavements. Here higher infiltration rates lead to a groundwater recharge that is greater than that of natural soils. The consequences from using these surfaces are already noticeable in many places through increasing groundwater levels. These increases cause damage to buildings. A second difference from a natural-soil water-balance is a lower evapotranspiration rate. Up to now the evaporation rates for water-permeable pavements has not been established accurately. The aim of the applied research project at the University of Muenster, which is sponsored by the DBU (The German Federal Environmental Foundation), is to gain knowledge of urban evaporation rates and of water-permeable surfaces, especially water-permeable pavements. Water-permeable pavements consist of the paving stone surface and the two sub-base layers below. Pre-investigations show that evaporation can be influenced by the complete sub-base. Therefore, the first step was to investigate which materials are used for sub-base construction. All in all, 27 materials were collected from throughout Germany and these materials were then tested (in terms of physical and hydraulic attributes) in

  5. Asphalt overlay design methods for rigid pavements considering rutting, reflection cracking, and fatigue cracking. Research report September 1996--August 1997

    SciTech Connect

    Cho, Y.H.; Liu, C.; Dossey, T.; McCullough, B.F.

    1998-10-01

    An asphalt concrete pavement (ACP) overlay over a rigid pavement represents a viable rehabilitation strategy. It can provide good serviceability at an initial construction cost that is substantially less than that of a rigid overlay rehabilitation. In addition, ACP overlays require less construction time, which can reduce user costs during construction. However, it may not be the most economical solution for long-term rehabilitation. Because of their relatively short service life, ACP overlays may require maintenance sooner than rigid overlays. And one of the more critical distresses that effectively determine the life span of the structure is reflection cracking. This report investigates alternative strategies that seek to prevent reflection cracking on ACP overlays.

  6. Assessment of in-situ compaction degree of HMA pavement surface layers using GPR and novel dielectric properties-based algorithms

    NASA Astrophysics Data System (ADS)

    Georgiou, Panos; Loizos, Fokion

    2015-04-01

    Field compaction of asphalt pavements is ultimately conducted to achieve layer(s) with suitable mechanical stability. However, the achieved degree of compaction has a significant influence on the performance of asphalt pavements. Providing all desirable mixture design characteristics without adequate compaction could lead to premature permanent deformation, excessive aging, and moisture damage; these distresses reduce the useful life of asphalt pavements. Hence, proper construction of an asphalt pavement is necessary to develop a long lasting roadway that will help minimize future maintenance. This goal is achieved by verifying and confirming that design specifications, in this case density specifications are met through the use of Quality Assurance (QA) practices. With respect to in-situ compaction degree of hot mix asphalt (HMA) pavement surface layers, nearly all agencies specify either cored samples or nuclear/ non nuclear density gauges to provide density measurement of the constructed pavement. Typically, a small number of spot tests (with either cores or nuclear gauges) are run and a judgment about the density level of the entire roadway is made based on the results of this spot testing. Unfortunately, density measurement from a small number of spots may not be representative of the density of the pavement mat. Hence, full coverage evaluation of compaction quality of the pavement mat is needed. The Ground Penetrating Radar (GPR), as a Non Destructive Testing (NDT) technique, is an example of a non-intrusive technique that favors over the methods mentioned above for assessing compaction quality of asphalt pavements, since it allows measurement of all mat areas. Further, research studies in recent years have shown promising results with respect to its capability, coupled with the use of novel algorithms based on the dielectric properties of HMA, to predict the in-situ field density. In view of the above, field experimental surveys were conducted to assess the

  7. Depression storage capacities of different ideal pavements as quantified by a terrestrial laser scanning-based method.

    PubMed

    Nehls, T; Menzel, M; Wessolek, G

    2015-01-01

    Rainfall partition on paved urban surfaces is governed to a great extent by depression storage. This is especially the case for small rainfall events, which are often ignored in urban hydrology. If storage, infiltration and evaporation (important for urban heat island mitigation), rather than storm water run-off, are of interest, high-resolution simulations with exact values for depression storage capacities are required. Terrestrial laser scanners deliver fast, high-resolution surveys of pavement surface morphology. The depression storage capacity can be quantified from 3D points by generating digital elevation models and applying cut-and-fill algorithms in a geographic information system. The method was validated using a test model. It was possible to quantify depressions with a depth of at least 1.4 × 10(-3) m and a surface of at least 15 × 10(-6) m(2) with an uncertainty below 30%. Applying this method, the depression storage capacities for 11 ideal, typical pavement designs were found to vary from 0.07 to 1.4 mm. Realistic urban pavements must also be surveyed, as cracks and puddles from their use history can have a major impact on the depression storage capacities and thus on infiltration, evaporation and, finally, the annual run-off. PMID:25812095

  8. Evaluation of clay content in soils for pavement engineering applications using GPR

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; Patriarca, Claudio; Benedetto, Andrea; Slob, Evert C.; Lambot, Sébastien

    2013-04-01

    Clay content significantly influences the mechanical behavior of soils, thereby playing an important role in many fields of applications such as civil engineering, geology and agriculture. In the area of pavement engineering, clay content in structural bearing courses of pavement frequently causes damages and defects, such as transversal and longitudinal cracks, or other faults. The main consequence is a lowering of both the road safety and operability, with the number of expected accidents increasing. In this study, ground-penetrating radar (GPR) laboratory tests were carried out to predict the clay amount in pavement structural layers under different clay and moisture conditions. GPR data processing is performed using two different methods. The first method is based on the Fresnel theory and focuses on the Rayleigh scattering of the radar waves. The approach is based on a different scattering of the various components of the frequency spectrum, mostly depending on both the soil texture and variation in soil moisture content. For the application of this method, we used a pulse radar with ground-coupled, 500 MHz centre-frequency antennas in a common offset, bistatic configuration. The transmitter and receiver were linked by optic fiber electronic modules. The second method is based on full-waveform inversion of the ultra wideband radar data. In particular, a specific radar-antenna electromagnetic model is used to filter out antenna effects and antenna-medium interactions from the raw radar data and retrieve the response of the soil only, expressed in terms of a layered medium Green's function. To estimate the medium geometrical and electrical values, an optimization inverse problem is formulated. For the application of that second method, we used a vector network analyzer (VNA) as continuous-wave stepped-frequency radar system to acquire data in the 500-3000 MHz frequency range. A doubled-ridged broadband horn antenna operating in far-field conditions was used as

  9. Medway Tunnel Road Pavement Survey Using Different Frequency GPR Antenna Systems - A Case Study

    NASA Astrophysics Data System (ADS)

    Alani, Morteza Amir; Banks, Kevin

    2015-04-01

    This presentation reports on an extensive survey carried out on a section (just outside the westbound end of the tunnel portal) of the Medway Tunnel in North Kent, UK. The Medway Tunnel provides a dual carriageway road crossing under the River Medway between Chatham and Strood. It is 725 metres long from portal to portal and consists of three sections. The appearance of repeated cracking of the road surface in this particular section of the tunnel suggested either a steady movement of the ground or possible undermining due to an underground watercourse. Ironically, the design and construction of the road had been realised to prevent any form of structural movement. It was deemed necessary to perform a Ground Penetrating Radar (GPR) survey in order to confirm underground construction details of the road in this section of the tunnel. This presentation reports on the detailed survey and the challenges encountered during the operation, which utilised four different frequency GPR systems including 2GHz, 900MHz, 600MHz and 200MHz antennas. The presentation will also describe how decisions were made to carry out supplementary surveys based on results obtained on-site (via primary data processing) and observations made during the survey. A summary of results will be presented individually for each antenna system used, as well as comparisons between each antenna system. Results will then be mapped against the design drawings available for confirmation of construction configurations. In conclusion, the presentation will demonstrate that the tunnel road pavement is not constructed as per the information provided (design drawings). Results will clearly indicate that there is no second reinforced concrete layer present in this particular section of the road pavement (contrary to what was originally believed) and will present the actual road construction in comparison with the design drawings. The results will confirm that there is no underground watercourse present in this

  10. Effectiveness of Pavement Management System and its Effects to the Closing of Final Account in Construction Project in Malaysia

    NASA Astrophysics Data System (ADS)

    Zakaria, Zarabizan; Ismail, Syuhaida; Yusof, Aminah Md

    2013-04-01

    Federal roads maintenance needs a systematic and effective mechanism to ensure that the roads are in good condition and provide comfort to the road user. In implementing effective maintenance, budget is main the factor limiting this endeavor. Thus Public Works Department (PWD) Malaysia used Highway Development and Management (HDM-4) System to help the management of PWD Malaysia in determining the location and length of the road to be repaired according to the priority based on its analysis. For that purpose, PWD Malaysia has applied Pavement Management System (PMS) which utilizes HDM-4 as the analysis engine to conduct technical and economic analysis in generating annual work programs for pavement maintenance. As a result, a lot of feedback and comment have been received from Supervisory and Roads Maintenance Unit (UPPJ) Zonal on the accuracy of the system output and problems that arise in the closing of final account. Therefore, the objective of this paper is to evaluate current system accuracy in terms of generating the annual work program for periodic pavement maintenance, to identify factors contributing to the system inaccuracy in selecting the location and length of roads that require for treatment and to propose improvement measures for the system accuracy. The factors affecting the closing of final account caused by result received from the pavement management system are also defined. The scope of this paper is on the existing HDM-4 System which cover four states specifically Perlis, Selangor, Kelantan and Johor which is analysed via the work program output data for the purpose of evaluating the system accuracy. The method used in this paper includes case study, interview, discussion and analysis of the HDM-4 System output data. This paper has identified work history not updated and the analysis is not using the current data as factors contributing to the system accuracy. From the result of this paper, it is found that HDM-4's system accuracy used by PWD

  11. a Feasibility Study on Use of Generic Mobile Laser Scanning System for Detecting Asphalt Pavement Cracks

    NASA Astrophysics Data System (ADS)

    Chen, Xinqu; Li, Jonathan

    2016-06-01

    This study aims to automatically detect pavement cracks on urban roads by employing the 3D point clouds acquired by a mobile laser scanning (MLS) system. Our method consists of four steps: ground point filtering, high-pass convolution, matched filtering, and noise removal. First, a voxel-based upward growing method is applied to construct Digital Terrain Model (DTM) of the road surface. Then, a high-pass filter convolutes the DTM to detect local elevation changes that may embed cracking information. Next, a two-step matched filter is applied to extract crack features. Lastly, a noise removal process is conducted to refine the results. Instead of using MLS intensity, this study takes advantages of the MLS elevation information to perform automated crack detection from large-volume, mixed-density, unstructured MLS point clouds. Four types of cracks including longitudinal, transvers, random, and alligator cracks are detected. Our results demonstrated that the proposed method works well with the RIEGL VMX-450 point clouds and can detect cracks in moderate-to-severe severity (13 - 25 mm) within a 200 m by 30 m urban road segment located in Kingston, Ontario, at one time. Due to the resolution capability, small cracks with slight severity remain unclear in the MLS point cloud.

  12. Production variability analysis of hot-mixed asphalt concrete containing reclaimed asphalt pavement. Final research report

    SciTech Connect

    Solaimanian, M.; Kennedy, T.W.

    1995-02-01

    A research project was undertaken to evaluate the production and construction variability of Hot Mix Asphalt Concrete (HMAC) containing high quantities of reclaimed asphalt pavement (RAP) material. Four construction projects were selected for this purpose. Two of the projects used 35 percent RAP material (both type-C mixes), while the other two used 40 percent (a type-B mix) and 50 percent (a type-D mix) of the RAP material, respectively. The projects differed in sizes, with total construction tonnage ranging from 10.9 million kg to 27.2 million kg (12,000 to 30,000 tons). In all cases, dedicated stockpiles of RAP material were used. Analysis was performed on the results obtained from the tests. The gradation and asphalt content deviations, air voids, penetration and viscosities, and stabilities, were included in the analysis. Pay adjustment factors were determined for gradation and asphalt content deviation, as well as for air voids (based on TxDOT Specification 3007). In general, these high-percent RAP projects indicated a variability higher than that of a typical HMAC without RAP. The pay adjustment factors for gradation and asphalt content deviation were lower than typical values. The construction gradations were finer than the job-mix formula target gradations, possibly a result of aggregate crushing during the milling operation.

  13. Minnesota`s experience using shingle scrap in bituminous pavements. Final report, 1991-1996

    SciTech Connect

    Janisch, D.W.; Turgeon, C.M.

    1996-10-01

    The Minnesota Department of Transportation (Mn/DOT) has experimented with the use of shingle scrap in hot mix asphalt (HMA) since 1990. To date, the source of the shingle scrap has been shingle manufacturers exclusively. The manufactured shingle scrap consists primarily of tab punch-outs but also contains some mis-colored and damaged shingles. Test sections were constructed on the Willard Munger Recreational Trail, T.H. 25 in Mayer, Minnesota and on County State Aid Highway (CSAH) 17, in Scott County, Minnesota. Not only are the test sections performing as well as the control sections, but using shingle scrap reduces the amount of virgin asphalt cement required in a bituminous mix, thus creating the potential for a cost savings when using shingle scrap in HMA. Based on the performance of these test sections, shingle manufacturing scrap is now an allowable salvage material in hot mix asphalt under Mn/DOT specification 2331.E2e, Recycled Mixture Requirements. This report outlines the history of shingle scrap use in Minnesota, presents laboratory and field performance data and contains the current Mn/DOT specifications allowing shingle scrap to be used as a salvage material in HMA pavements.

  14. An approach to the usage of polyethylene terephthalate (PET) waste as roadway pavement material.

    PubMed

    Gürü, Metin; Çubuk, M Kürşat; Arslan, Deniz; Farzanian, S Ali; Bilici, İbrahim

    2014-08-30

    This study investigates an application area for Polyethylene Terephthalate (PET) bottle waste which has become an environmental problem in recent decades as being a considerable part of the total plastic waste bulk. Two novel additive materials, namely Thin Liquid Polyol PET (TLPP) and Viscous Polyol PET (VPP), were chemically derived from waste PET bottles and used to modify the base asphalt separately for this aim. The effects of TLPP and VPP on the asphalt and hot mix asphalt (HMA) mixture properties were detected through conventional tests (Penetration, Softening Point, Ductility, Marshall Stability, Nicholson Stripping) and Superpave methods (Rotational Viscosity, Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR)). Also, chemical structures were described by Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectrometer (EDS) and Fourier Transform Infrared (FTIR) techniques. Since TLPP and VPP were determined to improve the low temperature performance and fatigue resistance of the asphalt as well as the Marshall Stability and stripping resistance of the HMA mixtures based on the results of the applied tests, the usage of PET waste as an asphalt roadway pavement material offers an alternative and a beneficial way of disposal of this ecologically hazardous material. PMID:25080154

  15. Subcellular and supracellular mechanical stress prescribes cytoskeleton behavior in Arabidopsis cotyledon pavement cells

    PubMed Central

    Sampathkumar, Arun; Krupinski, Pawel; Wightman, Raymond; Milani, Pascale; Berquand, Alexandre; Boudaoud, Arezki; Hamant, Olivier; Jönsson, Henrik; Meyerowitz, Elliot M

    2014-01-01

    Although it is a central question in biology, how cell shape controls intracellular dynamics largely remains an open question. Here, we show that the shape of Arabidopsis pavement cells creates a stress pattern that controls microtubule orientation, which then guides cell wall reinforcement. Live-imaging, combined with modeling of cell mechanics, shows that microtubules align along the maximal tensile stress direction within the cells, and atomic force microscopy demonstrates that this leads to reinforcement of the cell wall parallel to the microtubules. This feedback loop is regulated: cell-shape derived stresses could be overridden by imposed tissue level stresses, showing how competition between subcellular and supracellular cues control microtubule behavior. Furthermore, at the microtubule level, we identified an amplification mechanism in which mechanical stress promotes the microtubule response to stress by increasing severing activity. These multiscale feedbacks likely contribute to the robustness of microtubule behavior in plant epidermis. DOI: http://dx.doi.org/10.7554/eLife.01967.001 PMID:24740969

  16. Potential for localized groundwater contamination in a porous pavement parking lot setting in Rhode Island

    NASA Astrophysics Data System (ADS)

    Boving, Thomas B.; Stolt, Mark H.; Augenstern, Janelle; Brosnan, Brian

    2008-08-01

    The control of polluted surface runoff and the assessment of possible impacts on groundwater is a concern at the local and regional scale. On this background, a study investigates possible impacts of organic and inorganic pollutants (including bacteria) originating from a permeable asphalt parking lot on the water quality immediately beneath it. The functioning of the permeable pavement, including clogging and restricted vertical percolation, was also evaluated. Four nested sample ports (shallow and deep) were installed below low- and high-traffic areas, including one port outside the parking lot. At least initially there was a good hydraulic connection between the parking surface and the shallow sample ports. The presence of a geotextile layer at the base of the parking lot structure, however, was identified in lab tests as one factor restricting vertical percolation to the deeper ports. Clogging of the permeable surface was most pronounced in heavy traffic areas and below snow pile storage areas. Corroborated by high electric conductivity and chloride measurements, sand brought in by cars during winter was the principal cause for clogging. No bacteria or BOD were found in percolating water. Polycyclic aromatic hydrocarbons (PAH) were present at concentrations near minimum detection limit. Nutrients (nitrate and phosphate) were being leached into the ground via the permeable parking lot surface at annual flux rates of 0.45 0.84 g/m2/year. A multi-species tracer test demonstrated a retention capacity of the permeable parking lot structure of >90% for metals and 27% for nutrients, respectively.

  17. Feasibility for the use of coal tar as a new material for road surfaces (pavement) construction

    NASA Astrophysics Data System (ADS)

    Romero Farfán, M. A.; Murillo Vega, H. E.; Trujillo Pinto, F. A.

    2016-02-01

    The stabilization products often used to improve the support of granular layers in the construction of road surfaces may be expensive and difficult to get. Therefore, it is necessary to test different materials, which are cheap and easy to obtain, and which will enhance the physical and mechanical properties of pavement layers. This document evaluates the use of coal tar, as a stabilizer for granular subbase. Initially, with a description of tar properties, determining the optimal conditions for the granular subbase material compaction, by means of modified proctor tests and the calculation of the resistance of the unaltered material by using CBR lab tests (California Bearing Ratio). Afterwards, with the design and development of granular material mixes with different percentages of coal tar and determining its CBR as comparative parameter with that of the unaltered material. Finally, by calculating the optimal coal tar percentage in order to stabilize the subbase granular, the results showed an improvement in the resistance of the granular material and a decrease in its expansion due to the use of coal tar.

  18. Quantifying mobile and immobile zones during simulated stormwater infiltration through a new permeable pavement material.

    PubMed

    Bentarzi, Y; Ghenaim, A; Terfous, A; Wanko, A; Poulet, J B

    2015-01-01

    We have designed a new eco-material for use in permeable pavements in view to ensuring the sustainable management of stormwater in urban areas. The specific characteristic of this material is that it allows the infiltration of rainfall, storing the infiltrated water and trapping the pollutants carried by runoff such as engine oil and heavy metals. This new material is composed of a mixture of crushed concrete , resulting from inert construction waste, and organic material (compost). We performed tracing experiments in view to monitor the flow of the water within this material in order to study its hydrodynamics under heavy rainfall (rain with a return period of 10 years). The experimental results revealed preferential flows due to the heterogeneity of the material and liable to act as a major vector for the mobility of the pollutants transported within the material by stormwater. The work presented in this article consists in quantifying these preferential flows by determining their water contents in mobile (θm) and immobile (θim) water during infiltration. To do this, we used the (NON-EQUILIBRIUM Convection-Dispersion Equation) model, in order to evaluate mobile and stagnant zones in the framework of tracing experiments. PMID:25230252

  19. Evaluation of reclaimed rubber in bituminous pavements. Final report, July 1993-April 1995

    SciTech Connect

    Trepanier, J.

    1995-06-01

    Section 1038 of the 1991 Intermodel Surface Transportation efficiency Act (ISTEA) mandated use of crumb rubber from scrap tires in asphalt pavement starting in FY 94. To gain some experience, the Illinois Department of Transportation (IDOT) constructed five demonstration projects in 1993 and one in 1994. All used the `dry process` to introduce crumb rubber into the mix. With the dry process, crumb rubber is added to the heated aggregate prior to addition of asphalt cement (AC). Three projects used very low addition rates. Each was divided into five equal segments. One segment, the control, used no crumb rubber. The other segments used 1/2, 1, 1 1/2 and 2 pounds of crumb rubber per ton of hot mix. The other three projects each used 20 pounds of crumb rubber per ton of hot mix. Both batch plants and drier-drum plants were used, and the crumb rubber was supplied in pre-measured batch-size packets, 50-pound paper bags and 2000-pound super sacks.

  20. An Iterative Approach for the Optimization of Pavement Maintenance Management at the Network Level

    PubMed Central

    Torres-Machí, Cristina; Chamorro, Alondra; Videla, Carlos; Yepes, Víctor

    2014-01-01

    Pavement maintenance is one of the major issues of public agencies. Insufficient investment or inefficient maintenance strategies lead to high economic expenses in the long term. Under budgetary restrictions, the optimal allocation of resources becomes a crucial aspect. Two traditional approaches (sequential and holistic) and four classes of optimization methods (selection based on ranking, mathematical optimization, near optimization, and other methods) have been applied to solve this problem. They vary in the number of alternatives considered and how the selection process is performed. Therefore, a previous understanding of the problem is mandatory to identify the most suitable approach and method for a particular network. This study aims to assist highway agencies, researchers, and practitioners on when and how to apply available methods based on a comparative analysis of the current state of the practice. Holistic approach tackles the problem considering the overall network condition, while the sequential approach is easier to implement and understand, but may lead to solutions far from optimal. Scenarios defining the suitability of these approaches are defined. Finally, an iterative approach gathering the advantages of traditional approaches is proposed and applied in a case study. The proposed approach considers the overall network condition in a simpler and more intuitive manner than the holistic approach. PMID:24741352

  1. FEM analysis of dynamic behavior of asphalt pavement structure weakened by grassroots with account of hydraulic and vehicle load coupling effects

    NASA Astrophysics Data System (ADS)

    Huang, J.; Pan, X.; Dai, S. B.; Cai, Y.

    2015-12-01

    This paper establishes the finite element model of saturated asphalt pavement with ANSYS. The thickness and elastic modulus of pavement surface layers and grassroots are taken as influencing factors to analyze the influence of these factors’ change on the pavement mechanical behavior. The results indicate that the increase of surface thickness leads to the shear stress's decrease that may relieve the internal shear stress concentrated phenomenon effectively. The increase of elastic modulus of surface makes the pore pressure decrease, and result in the shear stress's increase. The grassroots thickness has no obvious effect on the pore- water pressure and shear stress; the grassroots elastic modulus’ increase may increase the internal shear stress and decrease the pore pressure.

  2. Design and implementation of PAVEMON: A GIS web-based pavement monitoring system based on large amounts of heterogeneous sensors data

    NASA Astrophysics Data System (ADS)

    Shahini Shamsabadi, Salar

    A web-based PAVEment MONitoring system, PAVEMON, is a GIS oriented platform for accommodating, representing, and leveraging data from a multi-modal mobile sensor system. Stated sensor system consists of acoustic, optical, electromagnetic, and GPS sensors and is capable of producing as much as 1 Terabyte of data per day. Multi-channel raw sensor data (microphone, accelerometer, tire pressure sensor, video) and processed results (road profile, crack density, international roughness index, micro texture depth, etc.) are outputs of this sensor system. By correlating the sensor measurements and positioning data collected in tight time synchronization, PAVEMON attaches a spatial component to all the datasets. These spatially indexed outputs are placed into an Oracle database which integrates seamlessly with PAVEMON's web-based system. The web-based system of PAVEMON consists of two major modules: 1) a GIS module for visualizing and spatial analysis of pavement condition information layers, and 2) a decision-support module for managing maintenance and repair (Mℝ) activities and predicting future budget needs. PAVEMON weaves together sensor data with third-party climate and traffic information from the National Oceanic and Atmospheric Administration (NOAA) and Long Term Pavement Performance (LTPP) databases for an organized data driven approach to conduct pavement management activities. PAVEMON deals with heterogeneous and redundant observations by fusing them for jointly-derived higher-confidence results. A prominent example of the fusion algorithms developed within PAVEMON is a data fusion algorithm used for estimating the overall pavement conditions in terms of ASTM's Pavement Condition Index (PCI). PAVEMON predicts PCI by undertaking a statistical fusion approach and selecting a subset of all the sensor measurements. Other fusion algorithms include noise-removal algorithms to remove false negatives in the sensor data in addition to fusion algorithms developed for

  3. Experimental and Numerical Studies of the Effects of Water Sprinkling on Urban Pavement on Heat Island Mitigation

    NASA Astrophysics Data System (ADS)

    Yoshioka, M.; Tosaka, H.; Nakagawa, K.

    2007-12-01

    One of the main causes of 'heat island phenomeno' is thought to be the artificial covers of the ground surface with asphalt or concrete which reduce greatly inherent cooling effect of water evaporation from soil surface. In this study, as a candidate method of mitigating the heat island the effects of the 'water sprinkling' on the pavements are discussed from field experiments and numerical studies. Three field experiments of water sprinkling on the asphalt/concrete pavements were performed in hot summer days in 2004-2006. For detecting the change in temperatures, the authors developed and used a 3-D measurements system which consists of two vertical planes with 6m high and 16m wide, and has network arrays of 102 thermistors distributed spatially in the planes. The temperatures measured in and around the water sprinkled area indicated that the ground surface temperature decreased 5 to 15 degrees uniformly in the water sprinkled area compared with those in the un-sprinkled area, while the relative decrease of atmospheric temperature was approximately up to 1 degree. The subsurface temperature at a depth of 14cm under the pavement decreased significantly and kept lower than that at the same depth in un-sprinkled area over the next morning. A numerical model was developed and applied to interpret the experimental results. It deals with the heat balance of radiation, sensible/latent heat transfer at the ground surface and heat conduction through the artificial and natural soil layer under ground. temperature and vapor conditions changes at and near ground surface were modeled by using the bulk formula.Good agreements between the calculated time-temperature profiles and the experimental ones were obtained by assuming adequate physical parameters and meteorological conditions. The model could be improved in order to evaluate the changes of temperature and vapor contents in atmosphere near the ground surface caused by aerodynamic turbulent diffusion.

  4. Simultaneous multi-vehicle detection and tracking framework with pavement constraints based on machine learning and particle filter algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Huang, Zhi; Zhong, Zhihua

    2014-11-01

    Due to the large variations of environment with ever-changing background and vehicles with different shapes, colors and appearances, to implement a real-time on-board vehicle recognition system with high adaptability, efficiency and robustness in complicated environments, remains challenging. This paper introduces a simultaneous detection and tracking framework for robust on-board vehicle recognition based on monocular vision technology. The framework utilizes a novel layered machine learning and particle filter to build a multi-vehicle detection and tracking system. In the vehicle detection stage, a layered machine learning method is presented, which combines coarse-search and fine-search to obtain the target using the AdaBoost-based training algorithm. The pavement segmentation method based on characteristic similarity is proposed to estimate the most likely pavement area. Efficiency and accuracy are enhanced by restricting vehicle detection within the downsized area of pavement. In vehicle tracking stage, a multi-objective tracking algorithm based on target state management and particle filter is proposed. The proposed system is evaluated by roadway video captured in a variety of traffics, illumination, and weather conditions. The evaluating results show that, under conditions of proper illumination and clear vehicle appearance, the proposed system achieves 91.2% detection rate and 2.6% false detection rate. Experiments compared to typical algorithms show that, the presented algorithm reduces the false detection rate nearly by half at the cost of decreasing 2.7%-8.6% detection rate. This paper proposes a multi-vehicle detection and tracking system, which is promising for implementation in an on-board vehicle recognition system with high precision, strong robustness and low computational cost.

  5. Oral exposure to commercially available coal tar-based pavement sealcoat induces murine genetic damage and mutations.

    PubMed

    Long, Alexandra S; Watson, Margaret; Arlt, Volker M; White, Paul A

    2016-08-01

    Coal tar (CT) is a thick black liquid produced as a by-product of coal carbonization to produce coke or manufactured gas. It is comprised a complex mixture of polycyclic aromatic compounds, including a wide range of polycyclic aromatic hydrocarbons (PAHs), many of which are genotoxic and carcinogenic. CT is used in some pavement sealants (also known as sealcoat), which are applied to pavement in order to seal and beautify the surface. Human exposure is known to occur not only during application, but also as a result of the weathering process, as elevated levels of PAHs have been found in settled house dust in residences adjacent to CT-sealed surfaces. In this study we examined the genotoxicity of an extract of a commercially available CT-based sealcoat in the transgenic Muta™Mouse model. Mice were orally exposed to 3 doses of sealcoat extract daily for 28 days. We evaluated genotoxicity by examining: (1) stable DNA adducts and (2) lacZ mutations in bone marrow, liver, lung, small intestine, and glandular stomach, as well as (3) micronucleated red blood cells. Significant increases were seen for each endpoint and in all tissues. The potency of the response differed across tissues, with the highest frequency of adducts occurring in liver and lung, and the highest frequency of mutations occurring in small intestine. The results of this study are the first demonstration of mammalian genotoxicity following exposure to CT-containing pavement sealcoat. This work provides in vivo evidence to support the contention that there may be adverse health effects in mammals, and potentially in humans, from exposure to coal tar. Environ. Mol. Mutagen. 57:535-545, 2016. © 2016 Her Majesty the Queen in Right of Canada. PMID:27473530

  6. Oral exposure to commercially available coal tar‐based pavement sealcoat induces murine genetic damage and mutations

    PubMed Central

    Watson, Margaret; Arlt, Volker M.; White, Paul A.

    2016-01-01

    Coal tar (CT) is a thick black liquid produced as a by‐product of coal carbonization to produce coke or manufactured gas. It is comprised a complex mixture of polycyclic aromatic compounds, including a wide range of polycyclic aromatic hydrocarbons (PAHs), many of which are genotoxic and carcinogenic. CT is used in some pavement sealants (also known as sealcoat), which are applied to pavement in order to seal and beautify the surface. Human exposure is known to occur not only during application, but also as a result of the weathering process, as elevated levels of PAHs have been found in settled house dust in residences adjacent to CT‐sealed surfaces. In this study we examined the genotoxicity of an extract of a commercially available CT‐based sealcoat in the transgenic Muta™Mouse model. Mice were orally exposed to 3 doses of sealcoat extract daily for 28 days. We evaluated genotoxicity by examining: (1) stable DNA adducts and (2) lacZ mutations in bone marrow, liver, lung, small intestine, and glandular stomach, as well as (3) micronucleated red blood cells. Significant increases were seen for each endpoint and in all tissues. The potency of the response differed across tissues, with the highest frequency of adducts occurring in liver and lung, and the highest frequency of mutations occurring in small intestine. The results of this study are the first demonstration of mammalian genotoxicity following exposure to CT‐containing pavement sealcoat. This work provides in vivo evidence to support the contention that there may be adverse health effects in mammals, and potentially in humans, from exposure to coal tar. Environ. Mol. Mutagen. 57:535–545, 2016. © 2016 Her Majesty the Queen in Right of Canada PMID:27473530

  7. Fracture-fault network characterization of pavement imagery of the Whitby Mudstone, Yorkshire

    NASA Astrophysics Data System (ADS)

    Boersma, Quinten; Hardebol, Nico; Houben, Maartje; Barnhoorn, Auke; Drury, Martyn

    2015-04-01

    Natural fractures play an important role in the hydrocarbon production from tight reservoirs. The need for fracture network pathways by fraccing matters particularly for shale gas prospects, due to their micro- to nano-darcies matrix permeabilities. The study of natural fractures from outcrops helps to better understand network connectivity and possibility of reactivating pre-existing planes of weakness, induced by hydraulic stimulation. Microseismicity also show that natural fractures are reactivated during fraccing in tight gas reservoirs and influence the success of the stimulation. An accurate understanding of natural fracture networks can help in predicting the development of fracture networks. In this research we analyze an outcrop analogue, the Whitby Mustone Formation (WMF), in terms of its horizontal fracture network. The WMF is the time equivalent of the Posidonia Shale Formation (PSF), which on itself is the main shale gas prospect in the Dutch subsurface. The fracture network of the WMF is characterized by a system of steep dipping joints with two dominant directions with N-S and E-W strike. The network was digitized from bird-view imagery of the pavement with a spatial extent of ~100 m at sub-cm resolution. The imagery is interpreted in terms of orientation and length distributions, intensity and fractal dimensions. Samples from the field were analyzed for rock strength and sample mineralogy. The results indicate that the fracture networks greatly differ per bed. Observed differences are for example; the geometry of the fracture network, its cumulative length distribution law, the fracture intensity, the fracture length vs its orientation and the fractal dimension. All these parameters greatly influence fracture network connectivity, the probability that longer fractures exist within the pavement and whether the network is more prone to clustering or scattering. Apart from the differences, the networks display a fairly similar orthogonal arrangement

  8. Potential applicability of stress wave velocity method on pavement base materials as a non-destructive testing technique

    NASA Astrophysics Data System (ADS)

    Mahedi, Masrur

    Aggregates derived from natural sources have been used traditionally as the pavement base materials. But in recent times, the extraction of these natural aggregates has become more labor intensive and costly due to resource depletion and environmental concerns. Thus, the uses of recycled aggregates as the supplementary of natural aggregates are increasing considerably in pavement construction. Use of recycled aggregates such as recycled crushed concrete (RCA) and recycled asphalt pavement (RAP) reduces the rate of natural resource depletion, construction debris and cost. Although recycled aggregates could be used as a viable alternative of conventional base materials, strength characteristics and product variability limit their utility to a great extent. Hence, their applicability is needed to be evaluated extensively based on strength, stiffness and cost factors. But for extensive evaluation, traditionally practiced test methods are proven to be unreasonable in terms of time, cost, reliability and applicability. On the other hand, rapid non-destructive methods have the potential to be less time consuming and inexpensive along with the low variability of test results; therefore improving the reliability of estimated performance of the pavement. In this research work, the experimental program was designed to assess the potential application of stress wave velocity method as a non-destructive test in evaluating recycled base materials. Different combinations of cement treated recycled concrete aggregate (RAP) and recycled crushed concrete (RCA) were used to evaluate the applicability of stress wave velocity method. It was found that, stress wave velocity method is excellent in characterizing the strength and stiffness properties of cement treated base materials. Statistical models, based on P-wave velocity were derived for predicting the modulus of elasticity and compressive strength of different combinations of cement treated RAP, Grade-1 and Grade-2 materials. Two

  9. Aquatic toxicity of airfield-pavement deicer materials and implications for airport runoff

    USGS Publications Warehouse

    Corsi, S.R.; Geis, S.W.; Bowman, G.; Failey, G.G.; Rutter, T.D.

    2009-01-01

    Concentrations of airfield-pavement deicer materials (PDM) in a study of airport runoff often exceeded levels of concern regarding aquatic toxicity. Toxicity tests on Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata (commonly known as Selenastrum capricornutum) were performed with potassium acetate (K-Ac) PDM, sodium formate (Na-For) PDM, and with freezing- point depressants (K-Ac and Na-For). Results indicate that toxicity in PDM is driven by the freezing-point depressants in all tests except the Vibrio fisheri test for Na-For PDM which is influenced by an additive. Acute toxicity end points for different organisms ranged from 298 to 6560 mg/L (as acetate) for K-Ac PDM and from 1780 to 4130 mg/L (as formate) for Na- For PDM. Chronic toxicity end points ranged from 19.9 to 336 mg/L (as acetate) for K-Ac PDM and from 584 to 1670 mg/L (as formate) for Na-For PDM. Sample results from outfalls at General Mitchell International Airport in Milwaukee, Wl (GMIA) indicated that 40% of samples had concentrations greater than the aquatic-life benchmark for K-Ac PDM. K-Ac has replaced urea during the 1990s as the most widely used PDM at GMIA and in the United States. Results of ammonia samples from airport outfalls during periods when urea-based PDM was used at GMIA indicated that41% of samples had concentrations exceeding the U.S. Environmental Protection Agency (USEPA) 1 -h water-quality criterion. The USEPA 1-h water-quality criterion for chloride was exceeded in 68% of samples collected in the receiving stream, a result of road-salt runoff from urban influence near the airport. Results demonstrate that PDM must be considered to comprehensively evaluate the impact of chemical deicers on aquatic toxicity in water containing airport runoff. ?? 2009 American Chemical Society.

  10. Traffic-generated emissions of ultrafine particles from pavement-tire interface

    NASA Astrophysics Data System (ADS)

    Dahl, Andreas; Gharibi, Arash; Swietlicki, Erik; Gudmundsson, Anders; Bohgard, Mats; Ljungman, Anders; Blomqvist, Göran; Gustafsson, Mats

    In a road simulator study, a significant source of sub-micrometer fine particles produced by the road-tire interface was observed. Since the particle size distribution and source strength is dependent on the type of tire used, it is likely that these particles largely originate from the tires, and not the road pavement. The particles consisted most likely of mineral oils from the softening filler and fragments of the carbon-reinforcing filler material (soot agglomerates). This identification was based on transmission electron microscopy studies of collected ultrafine wear particles and on-line thermal treatment using a thermodesorber. The mean particle number diameters were between 15-50 nm, similar to those found in light duty vehicle (LDV) tail-pipe exhaust. A simple box model approach was used to estimate emission factors in the size interval 15-700 nm. The emission factors increased with increasing vehicle speed, and varied between 3.7×10 11 and 3.2×10 12 particles vehicle -1 km -1 at speeds of 50 and 70 km h -1. This corresponds to between 0.1-1% of tail-pipe emissions in real-world emission studies at similar speeds from a fleet of LDV with 95% gasoline and 5% diesel-fueled cars. The emission factors for particles originating from the road-tire interface were, however, similar in magnitude to particle number emission factors from liquefied petroleum gas-powered vehicles derived in test bench studies in Australia 2005. Thus the road-tire interface may be a significant contributor to particle emissions from ultraclean vehicles.

  11. Dual-function growth medium and structural soil for use as porous pavement.

    PubMed

    Sloan, John J; Hegemann, Mary Ann; George, Steve A

    2008-01-01

    Permeable grass-covered surfaces can reduce the quantity of storm water runoff and filter out potentially harmful chemicals. The objective of this study was to develop permeable structural soils that sustained healthy turf growth and filtered heavy metals from contaminated pavement runoff. The basic soil medium was a 50:50 mixture (v/v) of expanded shale (ExSh) and quartz sand (QS). The ExSh component consisted of (i) large-diameter particles (3-6 mm), (ii) small-diameter particles (1-3 mm), or (iii) a 50:50 mixture (v/v) of the two. The basic blends were mixed with 0, 10, and 20% sphagnum peat moss (v/v) and 0, 10, and 20% natural zeolites (v/v) and placed in 15-cm-diameter pots in a greenhouse. Bermudagrass plugs were planted in each pot. The addition of sphagnum peat moss to the basic ExSh/QS blend increased bermudagrass growth and improved plant response to added fertilizer. Zeolites had no significant effect on plant growth in the absence of sphagnum peat moss. Growing mediums that contained 10 to 20% sphagnum peat moss and 10 to 20% zeolites consistently produced more bermudagrass biomass than the unamended ExSh/QS mixture. Changing the ratio of small- to large-diameter ExSh in the basic medium did not affect bermudagrass yield. Very low amounts of Cd, Cu, Pb, and Zn were recovered in leachate after the addition of 10 mg metal per pot, suggesting that most heavy metals (>99%) were retained in the growing mediums. Zeolites reduced the amount of Cd and Pb in leachate water, but not Cu or Zn. PMID:18948478

  12. Aquatic toxicity of airfield-pavement deicer materials and implications for airport runoff.

    PubMed

    Corsi, Steven R; Geis, Steven W; Bowman, George; Failey, Greg G; Rutter, Troy D

    2009-01-01

    Concentrations of airfield-pavement deicer materials (PDM) in a study of airport runoff often exceeded levels of concern regarding aquatic toxicity. Toxicity tests on Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata (commonly known as Selenastrum capricornutum) were performed with potassium acetate (K-Ac) PDM, sodium formate (Na-For) PDM, and with freezing-point depressants (K-Ac and Na-For). Results indicate that toxicity in PDM is driven by the freezing-point depressants in all tests except the Vibrio fisheri test for Na-For PDM which is influenced by an additive. Acute toxicity end points for different organisms ranged from 298 to 6560 mg/L (as acetate) for K-Ac PDM and from 1780 to 4130 mg/L (as formate) for Na-For PDM. Chronic toxicity end points ranged from 19.9 to 336 mg/L (as acetate) for K-Ac PDM and from 584 to 1670 mg/L (as formate) for Na-For PDM. Sample results from outfalls at General Mitchell International Airport in Milwaukee, WI (GMIA) indicated that 40% of samples had concentrations greater thanthe aquatic-life benchmarkfor K-Ac PDM. K-Ac has replaced urea during the 1990s as the most widely used PDM at GMIA and in the United States. Results of ammonia samples from airport outfalls during periods when urea-based PDM was used at GMIA indicated that 41% of samples had concentrations exceeding the U.S. Environmental Protection Agency (USEPA) 1-h water-quality criterion. The USEPA 1-h water-quality criterion for chloride was exceeded in 68% of samples collected in the receiving stream, a result of road-salt runoff from urban influence near the airport. Results demonstrate that PDM must be considered to comprehensively evaluate the impact of chemical deicers on aquatic toxicity in water containing airport runoff. PMID:19209582

  13. A study of sound absorption by street canyon boundaries and asphalt rubber concrete pavement

    NASA Astrophysics Data System (ADS)

    Drysdale, Graeme Robert

    A sound field model, based on a classical diffusion equation, is extended to account for sound absorption in a diffusion parameter used to model sound energy in a narrow street canyon. The model accounts for a single sound absorption coefficient, separate accommodation coefficients and a combination of separate absorption and accommodation coefficients from parallel canyon walls. The new expressions are compared to the original formula through numerical simulations to reveal the effect of absorption on sound diffusion. The newly established analytical formulae demonstrate satisfactory agreement with their predecessor under perfect reflection. As well, the influence of the extended diffusion parameter on normalized sound pressure levels in a narrow street canyon is in agreement with experimental data. The diffusion parameters are used to model sound energy density in a street canyon as a function of the sound absorption coefficient of the street canyon walls. The acoustic and material properties of conventional and asphalt rubber concrete (ARC) pavement are also studied to assess how the crumb rubber content influences sound absorption in street canyons. The porosity and absolute permeability of compacted specimens of asphalt rubber concrete are measured and compared to their normal and random incidence sound absorption coefficients as a function of crumb rubber content in the modified binder. Nonlinear trends are found between the sound absorption coefficients, porosity and absolute permeability of the compacted specimens and the percentage of crumb rubber in the modified binders. The cross-sectional areas of the air voids on the surfaces of the compacted specimens are measured using digital image processing techniques and a linear relationship is obtained between the average void area and crumb rubber content. The measured material properties are used to construct an empirical formula relating the average porosity, normal incidence noise reduction coefficients and

  14. Evaluation of Warm Mix Asphalt Technologies and Recycled Asphalt Pavements in Truckee Meadows, Nevada

    NASA Astrophysics Data System (ADS)

    Diaz Montecino, Cristian

    This study evaluated the properties and laboratory-performance of Hot Mix Asphalt (HMA) and Warm Mix Asphalt (WMA) mixtures with different levels of Recycled Asphalt Pavements (RAP) content: none for control mixtures, around 15% by dry weight of aggregates, and more than 30% by dry weight of aggregates. The rheological properties were evaluated for virgin and recovered RAP asphalt binders. The target amount of RAP in the mixtures was determined by using Blending Charts and Mortar Experiments. The mixtures are design through the guidelines established in Marshall Mix Design Method considering additional modifications for RAP and WMA from Superpave Mix Design. The mixtures are evaluated for their resistance to moisture damage by means of measuring the Dynamic Modulus |E*| after three freeze/thaw cycles and the indirect tensile strength after one and three freeze/thaw cycles. The resistance of the mixtures to permanent deformation was also evaluated by using the Asphalt Mixture Performance Tester (AMPT) to measure the flow number (FN). For this study, it was determined that the resistance to moisture damage decreases as the number of freeze/thaw cycles increases for most of the evaluated mixtures. Mixtures exhibited an increase in dynamic modulus as the RAP percentage increased. A decrease in the resistance to moisture damage was detected with the increase in RAP content for most of the mixtures. HMA mixtures exhibited a better performance in rutting than the WMA mixtures. An increase in rutting resistance was observed with the increase in RAP percentage for HMA mixtures whereas an inconsistent trend was observed for WMA mixtures. Further study is needed to validate the use of the high percentage of RAP in Washoe County.

  15. The Impact of Cloud Type on Surface Radiation and Road Pavement Temperature

    NASA Astrophysics Data System (ADS)

    Walker, C. L.; Anderson, A.; Chapman, M.; Drobot, S.

    2012-12-01

    Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with winter road maintenance. The racing community also relies on racetrack pavement temperature forecast systems because tire friction decreases as temperature increases, affecting vehicle performance. Race crews perform vehicle maintenance (e.g., tire pressure and suspension adjustments) to maximize traction given a forecasted racetrack temperature. Many forecast systems suffer from inaccurate radiation forecasts resulting in part from a lack of information relating radiation to cloud types. This research seeks to improve the forecasts by determining how cloud type impacts the amount of solar radiation reaching the surface. Cloud type information was obtained from the Naval Research Laboratory Cloud Classifier algorithm and radiation data were obtained from a Davis Weather Station. A theoretical maximum solar radiation distribution was calculated. Cloud type-radiation distribution analyses from Salisbury, North Carolina during May-June 2012 indicated that low clouds allowed approximately 20% of the maximum possible radiation to reach the surface, mid level clouds 32%, high clouds 40% and cumuliform types 34%. A categorical regression analysis revealed 33% of the variation in solar radiation on cloudy case days can be explained by cloud type. Inclusion of clear case days with apparent variability lowered this to 7% suggesting another influence on radiation. A similar bulk statistical analysis is in progress on a much larger data set obtained from the Oklahoma Mesonet. This work lays the foundation for use of satellite cloud type information in order to improve the output of forecast systems. Distribution of mean solar radiation measured at the surface for all nine case studies, sorted by cloud type height characteristics, where n represents the sample size.

  16. Stormwater infiltration and surface runoff pollution reduction performance of permeable pavement layers.

    PubMed

    Niu, Zhi-Guang; Lv, Zhi-Wei; Zhang, Ying; Cui, Zhen-Zhen

    2016-02-01

    In this paper, the laboratory-scale permeable pavement layers, including a surface permeable brick layer, coarse sand bedding layers (thicknesses = 2, 3.5, and 5 cm), and single-graded gravel sub-base layers (thicknesses = 15, 20, 25, and 30 cm), were built to evaluate stormwater infiltration and surface runoff pollution reduction performance. And, the infiltration rate (I) and concentrations of suspended solids (SS), total phosphorus (TP), chemical oxygen demand (COD), ammonia nitrogen, and total nitrogen (TN) were measured under the simulated rainfall intensity of 72.4 mm/h over duration of 60 min. The results indicate that the thickness factor primarily influences the infiltration rate and pollutant removal rate. The highest steady infiltration rate was for surface brick layer 51.0 mm/h, for 5-cm sand bedding layer 32.3 mm/h, and for 30-cm gravel sub-base layer 42.3 mm/h, respectively. The SS average removal rate was relative higher (79.8 ∼ 98.6 %) for all layers due to the interception and filtration. The average removal rates of TP and COD were for surface layer 71.2 and 24.1 %, for 5-cm bedding layer 54.8 and 9.0 %, and for 20-cm sub-base layer 72.2 and 26.1 %. Ammonia nitrogen and TN cannot steadily be removed by layers according to the experiment results. The optimal thickness of bedding sands was 5 cm, and that of sub-base gravels was 20 ∼ 30 cm. PMID:26429141

  17. Effects of composition and exposure on the solar reflectance of Portland Cement Concrete

    SciTech Connect

    Levinson, Ronnen; Akbari, Hashem

    2002-06-01

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Lower air temperatures decrease demand for cooling energy and slow the formation of urban smog. Variations with composition and environmental exposure of the albedos of portland cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Concrete albedo generally correlated with cement albedo and sand albedo and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance of concrete. Simulated weathering, soiling, and abrasion each reduced average concrete albedo, though some samples became slightly more reflective through weathering or soiling. Concrete albedo grew as the cement hydration reaction progressed, but stabilized within six weeks of casting.

  18. Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert

    2015-06-01

    Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors.

  19. Formation of gravel pavements during fluvial erosion as an explanation for persistence of ancient cratered terrain on Titan and Mars

    NASA Astrophysics Data System (ADS)

    Howard, Alan D.; Breton, Sylvain; Moore, Jeffrey M.

    2016-05-01

    In many terrestrial channels the gravel bed is only transported during rare floods (threshold channels), and rates of erosion are very slow. In this paper we explore how coarse debris delivered to channels on Mars and Titan from erosion may inhibit further erosion once a coarse gravel channel bed develops. Portions of the equatorial region of Titan are fluvially eroded into banded (crenulated) terrain, some of which contains numerous circular structures that are likely highly degraded large impact craters surviving from the late heavy bombardment. No mechanism that can chemically or physically break down ice (likely the most important component of Titans crust) has been unambiguously identified. This paper examines a scenario in which fluvial erosion on Titan has largely involved erosion into an impact-generated megaregolith that contains a modest component of gravel-sized debris. As the megaregolith is eroded, coarse gravel gradually accumulates as a lag pavement on channel beds, limiting further erosion and creating a dissected, but largely inactive, or senescent, landscape. Similar development of gravel pavements occur in ancient mountain belts on Earth, and partially explain the persistence of appreciable relief after hundreds of millions of years. Likewise, coarse gravel beds may have limited the degree to which erosion could modify the heavily cratered terrains on Mars, particularly if weathering were largely due to physical, rather than chemical weathering processes in a relatively cold and/or arid environment.

  20. Deterioration of the volcanic kerb and pavement stones in a humid environment in the city centre of Izmir, Turkey

    NASA Astrophysics Data System (ADS)

    Yavuz, A. B.

    2006-11-01

    İzmir is the third largest city in Turkey and has being the centre of art, culture, tourism and trade activities throughout the 5,000 years of its history. Natural stones brought from different parts of the world have been widely used for construction of the prestigious buildings, monuments and roads etc., in the past in the city. Renovation of the street pavements and public gathering areas in the city centre has been undertaken by the Metropolitan Municipality in 2000 and continued through the year of 2001. These renovation activities have mainly been carried out in the streets running parallel to the sea shore. Volcanic rocks brought from the Central Anatolia Ankara-Gölbaşı (andesites) and Kayseri-İncesu (tuffs) have been used in the renovation works. These rocks have shown extensive deteriorations within 4 years of their usage between 2001 and 2005 under the influence of different environmental factors. In this study, the deteriorations developed in the recently placed volcanic rocks used as kerb and pavement stones in the city centre of İzmir in the light of their mineralogical, chemical, physical and mechanical properties, used locations and the environmental factors are presented.

  1. In-depth study of cold in-place recycled-pavement performance. Volume 1. Final report. Rept. for Dec 88-Oct 90

    SciTech Connect

    Scholz, T.V.; Hicks, R.G.; Rogge, D.F.

    1990-12-01

    Oregon has developed a mix design procedure for cold in-place recycled (CIR) asphalt concrete pavements. The procedure involves estimation of an initial emulsion content based on gradation of recycled asphalt pavement (RAP), asphalt content of RAP, and penetration and viscosity of recovered asphalt. When an estimated emulsion content is determined, Marshall-sized specimens are prepared for a range of emulsion contents with the range centered on the estimated emulsion content. Hveem and Marshall stability, resilient modulus, and index of retained modulus (IRM) tests are performed on the specimens and a design emulsion content is selected based upon these results. Because of variations in RAP properties, continual need for field adjustments, and the difficulty of interpreting mix property test results, only the estimation part of the procedure is currently implemented. The paper describes the mix design procedure and presents lab results demonstrating the difficulty of choosing emulsion content based on Hveem and Marshall stability, resilient modulus and IRM. Data comparing design emulsion content with actual emulsion contents used in the field are presented. Selection of water content is discussed. Test results of mix properties monitored over time are presented, demonstrating the curing of the emulsion. Performance data for CIR pavements constructed from 1984 through 1988 are presented as well as initial results of an attempt to use lime during recycling to correct a stripped pavement. A construction and inspection manual is presented as a separate document.

  2. Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

    PubMed

    Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

    2016-03-15

    The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material. PMID:26735865

  3. In-situ infiltration performance of different permeable pavements in a employee used parking lot--A four-year study.

    PubMed

    Kumar, Kuldip; Kozak, Joseph; Hundal, Lakhwinder; Cox, Albert; Zhang, Heng; Granato, Thomas

    2016-02-01

    Permeable pavements are being adopted as a green solution in many parts of the world to manage urban stormwater quantity and quality. This paper reports on the measured in-situ infiltration performance over a four-year period since construction and use of three permeable parking sections (permeable pavers, permeable concrete and permeable asphalt) of an employee car parking lot. There was only a marginal decline in infiltration rates of all three pavements after one year of use. However, between years two to four, the infiltration rates declined significantly due to clogging of pores either by dry deposition of particles and/or shear stress of vehicles driving and degrading the permeable surfaces; during the last two years, a greater decline was also observed in driving areas of the parking lots compared to parking slots, where minimal wear and tear are expected. Maintenance strategies were employed to reclaim some of the lost infiltration rate of the permeable pavements to limited success. Despite this decline, the infiltration rates were still four to five times higher than average rainstorm intensity in the region. Thus, these permeable pavement parking lots may have significant ecological importance due to their ability to infiltrate rainwater quickly, reduce the runoff in the catchment area, and also dampen runoff peak flows that could otherwise enter the collection system for treatment in a combined sewer area. PMID:26606196

  4. Pavements Maintenance and Construction Equipment Operator Career Ladders: United States Air Force Job Inventory. AFSCs 55130/31, 55150/51, 55170/71, and 55191.

    ERIC Educational Resources Information Center

    Air Force Personnel and Training Research Center, Lackland AFB, TX.

    The U. S. Air Force job inventory for the pavements maintenance and construction equipment operator career ladders is divided into 26 categories, each of which is broken down into a duty-task list. Space is provided for Air Force personnel filling out the inventory to check whether each task is at present part of their duties. The 26 categories…

  5. Analysis of Instrumentation Selection and Placement to Monitor the Hydrologic Performance of Permeable Pavement Systems and Bioinfiltration Areas at the Edison Environmental Center in New Jersey

    EPA Science Inventory

    In 2009, the U.S. Environmental Protection Agency constructed a 0.4-ha (1-ac) parking lot surfaced with three different permeable pavement types (interlocking concrete pavers, porous concrete, and porous asphalt) and six bioinfiltration areas with three different drainage area to...

  6. Aircraft and Pavement Deicer and Anti-Icer Forensics: Which Formulations Reach the Receiving Water and What are Their Potential Impacts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To characterize the effects from runoff of aircraft deicer and anti-icer fluid (ADAF) and pavement deicer formulations (PDF) on receiving water, multiple deicing and anti-icing formulations must be considered. ADAF formulations used on aircraft include Type I fluids (deicers) and Type IV fluids (an...

  7. Comparative Occupational Survey of Civilian and Military Members in the Pavements Maintenance and Construction Equipment Operator Specialties. Final Report for Period 1 October 1975-30 October 1977.

    ERIC Educational Resources Information Center

    Cowan, Douglas K.

    A study was conducted to analyze and compare the job performance of civil service and military pavements maintenance workers and construction equipment operators. A military sample of 2,675 and a civilian sample of 1,974 were surveyed by means of a job inventory checklist and relative time spent rating method. Of the three job types that were…

  8. PAH Concentrations Decline Following 2006 Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas

    NASA Astrophysics Data System (ADS)

    Van Metre, P. C.; Mahler, B. J.

    2013-12-01

    Recent studies have concluded that coal-tar-based pavement sealants (CT sealants) are a major source of polycyclic aromatic hydrocarbons (PAHs) in non-industrial urban settings in the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of CT sealants. We evaluated PAH concentrations following the ban by analyzing sediment cores collected from Lady Bird Lake in 2012; Lady Bird Lake impounds the Colorado River in central Austin and receives runoff from much of the greater Austin area. The mean sum concentration of the 16 U.S. Environmental Protection Agency Priority Pollutant PAHs (∑PAH16) in one of two 2012 sediment cores analyzed for PAHs declined 75% from before 2006 (mean of 4 samples=8,090 μg kg-1) to 2012 (mean of 2 samples=2,030 μg kg-1), reversing a 40-year (1959-1999) upward trend in PAH concentrations that was previously documented. The downward trend in PAH concentrations in the seven uppermost 1 cm sampling intervals in the first 2012 core was statistically significant (r=0.93, p-value=0.002). Post-2008 PAH trends in the second 2012 core were similar (significant downward trend in the six uppermost 1 cm sampling intervals and mean 2012 ∑PAH16 of 2,390 μg kg-1); however, pre-2007 sediment did not appear to have been preserved in this core likely because of the effects of flooding on sediment deposition and mixing at this site--the largest flood on the Colorado River in Austin in 20 years was in 2007. On the basis of a comparison of lake-sediment PAH profiles to 22 PAH source profiles, the PAH loading to lake sediment continues to be dominated by CT sealants. The continued dominance of proportional PAH loading by CT sealants in spite of decreased concentrations since 2006 might be because legacy CT sealant and contaminated soils and sediments continue to yield PAHs to runoff. A previous study using source-receptor modeling concluded that CT sealants were the largest PAH source to 40 urban lakes studied in the

  9. Some advances/results in monitoring road cracks from 2D pavement images within the scope of the collaborative FP7 TRIMM project

    NASA Astrophysics Data System (ADS)

    Baltazart, Vincent; Moliard, Jean-Marc; Amhaz, Rabih; Wright, Dean; Jethwa, Manish

    2015-04-01

    Monitoring road surface conditions is an important issue in many countries. Several projects have looked into this issue in recent years, including TRIMM 2011-2014. The objective of such projects has been to detect surface distresses, like cracking, raveling and water ponding, in order to plan effective road maintenance and to afford a better sustainability of the pavement. The monitoring of cracking conventionally focuses on open cracks on the surface of the pavement, as opposed to reflexive cracks embedded in the pavement materials. For monitoring surface condition, in situ human visual inspection has been gradually replaced by automatic image data collection at traffic speed. Off-line image processing techniques have been developed for monitoring surface condition in support of human visual control. Full automation of crack monitoring has been approached with caution, and depends on a proper manual assessment of the performance. This work firstly presents some aspects of the current state of monitoring that have been reported so far in the literature and in previous projects: imaging technology and image processing techniques. Then, the work presents the two image processing techniques that have been developed within the scope of the TRIMM project to automatically detect pavement cracking from images. The first technique is a heuristic approach (HA) based on the search for gradient within the image. It was originally developed to process pavement images from the French imaging device, Aigle-RN. The second technique, the Minimal Path Selection (MPS) method, has been developed within an ongoing PhD work at IFSTTAR. The proposed new technique provides a fine and accurate segmentation of the crack pattern along with the estimation of the crack width. HA has been assessed against the field data collection provided by Yotta and TRL with the imaging device Tempest 2. The performance assessment has been threefold: first it was performed against the reference data set

  10. Mono-static GPR without transmitting anything for pavement damage inspection: interferometry by auto-correlation applied to mobile phone signals

    NASA Astrophysics Data System (ADS)

    Feld, R.; Slob, E. C.; Thorbecke, J.

    2015-12-01

    Creating virtual sources at locations where physical receivers have measured a response is known as seismic interferometry. A much appreciated benefit of interferometry is its independence of the actual source locations. The use of ambient noise as actual source is therefore not uncommon in this field. Ambient noise can be commercial noise, like for example mobile phone signals. For GPR this can be useful in cases where it is not possible to place a source, for instance when it is prohibited by laws and regulations. A mono-static GPR antenna can measure ambient noise. Interferometry by auto-correlation (AC) places a virtual source on this antenna's position, without actually transmitting anything. This can be used for pavement damage inspection. Earlier work showed very promising results with 2D numerical models of damaged pavement. 1D and 2D heterogeneities were compared, both modelled in a 2D pavement world. In a 1D heterogeneous model energy leaks away to the sides, whereas in a 2D heterogeneous model rays can reflect and therefore still add to the signal reconstruction (see illustration). In the first case the amount of stationary points is strictly limited, while in the other case the amount of stationary points is very large. We extend these models to a 3D world and optimise an experimental configuration. The illustration originates from the journal article under submission 'Non-destructive pavement damage inspection by mono-static GPR without transmitting anything' by R. Feld, E.C. Slob, and J.W. Thorbecke. (a) 2D heterogeneous pavement model with three irregular-shaped misalignments between the base and subbase layer (marked by arrows). Mono-antenna B-scan positions are shown schematically. (b) Ideal output: a real source at the receiver's position. The difference w.r.t. the trace found in the middle is shown. (c) AC output: a virtual source at the receiver's position. There is a clear overlap with the ideal output.

  11. Stormwater quality performance of a macro-pervious pavement car park installation equipped with channel drain based oil and silt retention devices.

    PubMed

    Newman, Alan Paul; Aitken, Douglas; Antizar-Ladislao, Blanca

    2013-12-15

    This paper reports the results of a two year field monitoring exercise intended to investigate the pollution abatement capabilities of a novel system which offers an alternative to the, now well established, pervious pavement system as a source control device for stormwater management. The aim of this study was to determine the effectiveness of a live installation of a macro-pervious pavement system (MPPS) (operated as a visitors' car park at a prison in Central Scotland) in retaining and treating a range of pollutants which originate from automobile use or become concentrated on the parking surface from the wider environment. The MPPS is a sub-class of pervious pavement system where the vast majority of the surface is impermeable. It directs stormwater into a pervious sub surface storage/attenuation zone through a series of distinct infiltration points fast enough to prevent flooding during the design storm. In the particular system studied here the infiltration points consist of a network of oil/silt separation devices with extensive further pollutant retention/degradation provided during the passage of stormwater through the sub surface zone. Approximately 12 months after the car park was completed a sampling regime was instigated in which grab samples were collected at intervals from each of the three sub catchments whilst, simultaneously, samples were collected directly from the, pollutant retaining, infiltration devices. Through investigation of samples collected at the upstream end of the system, the retention of significant amounts of hydrocarbons and heavy metals in the initial collection devices has been illustrated and the analysis of effluent samples collected at the outlet points indicate that the system is capable of producing effluent which is of a standard comparable to that expected from a traditional pervious pavement system and is acceptable for direct release into a surface water receptor. The system offers the opportunity to accrue the benefits

  12. Cortisol affects tight junction morphology between pavement cells of rainbow trout gills in single-seeded insert culture.

    PubMed

    Sandbichler, Adolf Michael; Farkas, Julia; Salvenmoser, Willi; Pelster, Bernd

    2011-12-01

    A primary culture system of rainbow trout gill pavement cells grown on permeable support (single-seeded insert, SSI) was used to examine histological and physiological changes induced by the addition of the corticosteroid hormone cortisol. Pavement cell epithelia were cultured under symmetrical conditions (L15 apical/L15 basolateral) and developed a high transepithelial resistance (TER, 6.84 ± 1.99 kΩ cm(2), mean ± SEM) with a low phenol red diffusion rate (PRD, 0.15 ± 0.03 μmol l(-1)/day). Addition of cortisol to the basolateral compartment increased TER twofold and reduced PRD threefold over a 5-day period. A similar increase in TER could be seen after 24 h apical freshwater (FW) in control cultures. In cortisol-treated cultures FW exposure did not change TER, but PRD increased significantly. Histochemical staining of the cytoskeleton of cells in SSI culture revealed a morphological partitioning into a single mucosal layer of polarized, polygonal cells featuring cortical F-actin rings which were comparable to F-actin rings of epithelial cells on the lamellar and filamental surface, and several unorganized serosal layers of cells with F-actin stress fibers. Addition of cortisol increased cell density by 18% and in the mucosal layer it led to smaller, less polygonal cells with increased height and increased cell contact area. In transmission electron microscopic images two pairs of cytoplasmatic electron-dense structures confining the zonula occludens apically and basally toward the zonula adhaerens were found. Addition of cortisol increased the distance between those paired structures, hence led to deeper tight junctions. The cortisol-induced increase in barrier properties, therefore, involves a structural fortification of the tight junctions which was not generally modified by a short 24-h apical freshwater stress. These results identify cortisol as a regulator of tight junction morphology between pavement cells of euryhaline fish such as the

  13. Investigation of Self Consolidating Concrete Containing High Volume of Supplementary Cementitious Materials and Recycled Asphalt Pavement Aggregates

    NASA Astrophysics Data System (ADS)

    Patibandla, Varun chowdary

    The use of sustainable technologies such as supplementary cementitiuous materials (SCMs), and/or recycled materials is expected to positively affect the performance of concrete mixtures. However, it is important to study and qualify such mixtures and check if the required specifications of their intended application are met before they can be implemented in practice. This study presents the results of a laboratory investigation of Self Consolidating concrete (SCC) containing sustainable technologies. A total of twelve concrete mixtures were prepared with various combinations of fly ash, slag, and recycled asphalt pavement (RAP). The mixtures were divided into three groups with constant water to cementitiuous materials ratio of 0.37, and based on the RAP content; 0, 25, and 50% of coarse aggregate replaced by RAP. All mixtures were prepared to achieve a target slump flow equal to or higher than 500 mm (24in). A control mixture for each group was prepared with 100% Portland cement whereas all other mixtures were designed to have up to 70% of portland cement replaced by a combination of supplementary cementitiuous materials (SCMs) such as class C fly ash and granulated blast furnace slag. The properties of fresh concrete investigated in this study include flowability, deformability; filling capacity, and resistance to segregation. In addition, the compressive strength at 3, 14, and 28 days, the tensile strength, and the unrestrained shrinkage up to 80 days was also investigated. As expected the inclusion of the sustainable technologies affected both fresh and hardened concrete properties. Analysis of the experimental data indicated that inclusion of RAP not only reduces the ultimate strength, but it also affected the compressive strength development rate. Moreover, several mixes satisfied compressive strength requirements for pavements and bridges; those mixes included relatively high percentages of SCMs and RAP. Based on the results obtained in this study, it is not

  14. Stormwater harvesting for irrigation purposes: an investigation of chemical quality of water recycled in pervious pavement system.

    PubMed

    Nnadi, Ernest O; Newman, Alan P; Coupe, Stephen J; Mbanaso, Fredrick U

    2015-01-01

    Most available water resources in the world are used for agricultural irrigation. Whilst this level of water use is expected to increase due to rising world population and land use, available water resources are expected to become limited due to climate change and uneven rainfall distribution. Recycled stormwater has the potential to be used as an alternative source of irrigation water and part of sustainable water management strategy. This paper reports on a study to investigate whether a sustainable urban drainage system (SUDS) technique, known as the pervious pavements system (PPS) has the capability to recycle water that meets irrigation water quality standard. Furthermore, the experiment provided information on the impact of hydrocarbon (which was applied to simulate oil dripping from parked vehicles onto PPS), leaching of nutrients from different layers of the PPS and effects of nutrients (applied to enhance bioremediation) on the stormwater recycling efficiency of the PPS. A weekly dose of 6.23 × 10(-3) L of lubricating oil and single dose of 17.06 g of polymer coated controlled-release fertilizer granules were applied to the series of 710 mm × 360 mm model pervious pavement structure except the controls. Rainfall intensity of 7.4 mm/h was applied to the test models at the rate of 3 events per week. Analysis of the recycled water showed that PPS has the capability to recycle stormwater to a quality that meets the chemical standards for use in agricultural irrigation irrespective of the type of sub-base used. There is a potential benefit of nutrient availability in recycled water for plants, but care should be taken not to dispose of this water in natural water courses as it might result in eutrophication problems. PMID:25256837

  15. Development and application of laboratory and geophysical methods for the determination of hydraulic properties on desert pavements in the Mojave Desert

    NASA Astrophysics Data System (ADS)

    Meadows, Darren G.

    Interactions between pedologic development and hydrology have important implications for arid ecosystems and landscape evolution. The ability to rapidly evaluate hydraulic properties of a soil would greatly enhance our ability to study these relationships. The purpose of this work was (1) to develop a method for determining the hydraulic properties of structured soil peds; (2) to use the method to investigate the impact of surface age on the hydraulic properties; and (3) to investigate the efficacy of noninvasive geophysical methods for estimation of clay content and hydraulic properties of surface soils in arid environments. This work was conducted on multiple aged desert pavements in the Mojave National Preserve, California. To more fully investigate the mechanism of infiltration on desert pavements, we first ran a tension infiltrometer experiment on a well-developed pavement to determine the field hydraulic properties. The area directly underneath the disc was then excavated and brought to the laboratory. The peds that comprised the disc area were individually sampled using the newly developed method, which is a combination of the traditional evaporation experiment and parameter estimation. Hydraulic properties of the individual peds were then areally averaged and compared with the field-determined values. A comparison of the two methods provides an indication of the impact of the interped region on the hydraulic properties because the laboratory method sampled only the peds, whereas the field method sampled both peds and the interped cracks that separate them in the field. This method was then used on three different pavements of varying age (10 ka, 100 ka, and ˜600 ka), with triplicate measurements on each surface. Although the 600 ka is the oldest surface, the Av horizon and desert pavement mantling this surface is similar in age to the 10 ka because the original soil has been stripped and the horizon re-formed, making the Qf3 the oldest surface soil

  16. Numerical modeling of gravel bed river response to meander straightening: The coupling between the evolution of bed pavement and long profile

    NASA Astrophysics Data System (ADS)

    Talbot, Tracey; Lapointe, Michel

    2002-06-01

    Artificial meander straightening (rectification) was conducted in the early 1960s along the Sainte-Marguerite River, Canada, in order to facilitate highway construction along the valley. Previous studies [Talbot and Lapointe, 2002] confirm that vertical reprofiling, coupled with pavement coarsening in the degrading reach, were the main responses counteracting the disequilibrium in gravel transport rates triggered at rectification of this system. Numerical simulations, using SEDROUT2.0, a one-dimensional hydraulic and sediment transport model, and validated against the observed channel response, show the important role played by an advancing wave of pavement coarsening down the rectified reach in modulating the bed degradation response. Simulations extending into the future reveal an asymptotically slowing approach to equilibrium in the middle of the 21st century, with a response half-time of the order of 10 years. In near-threshold gravel bed systems like the Sainte-Marguerite River, pavement coarsening after rectification buffers the system against extreme degradation. Most significantly for watershed management, this also appears to severely limit the extent of propagation of degradation upstream of the rectification.

  17. A method for assessing the physical recovery of Antarctic desert pavements following human-induced disturbances: a case study in the Ross Sea region of Antarctica.

    PubMed

    O'Neill, Tanya A; Balks, Megan R; López-Martínez, Jerónimo; McWhirter, Judi L

    2012-12-15

    With increasing visitor numbers an understanding of the impacts of human activities in Antarctic terrestrial environments has become important. The objective of this study was to develop a means for assessing recovery of the ground surface desert pavement following physical disturbance. A set of 11 criteria were identified to assess desert pavement recovery. Assessed criteria were: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m(2); colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity/extent rating on a scale from zero to four, zero being highly disturbed, and four being undisturbed. A relative % recovery for each criteria was calculated for each site by comparison with a nearby undisturbed control area, and an overall Mean Recovery Index (MRI) was assigned to each pavement surface. To test the method, 54 sites in the Ross Sea region of Antarctica were investigated including areas disturbed by: bulldozer scraping for road-fill, contouring for infrastructure, geotechnical investigations, and experimental treading trial sites. Disturbances had occurred at timescales ranging from one week to 50 years prior to assessment. The extent of desert pavement recovery at the sites investigated in this study was higher than anticipated. Fifty of the 54 sites investigated were in an intermediate, or higher, stage of desert pavement recovery, 30 sites were in an advanced stage of recovery, and four sites were indistinguishable from adjacent control sites (MRI = 100%). It was found that active surfaces, such as the gravel beach deposits at the Greenpeace World Park Base site at Cape Evans, the aeolian sand deposits at Bull Pass, and the alluvial fan deposits of the Loop Moraine field campsite, recovered relatively

  18. Strain distribution and crack detection in thin unbonded concrete pavement overlays with fully distributed fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Bao, Yi; Chen, Genda

    2016-01-01

    This study aims at evaluating the feasibility of strain measurement and crack detection in thin unbonded concrete pavement overlays with pulse prepump Brillouin optical time domain analysis. Single-mode optical fibers with two-layer and three-layer coatings, respectively, were applied as fully distributed sensors, their performances were compared with analytical predictions. They were successfully protected from damage during concrete casting of three full-scale concrete panels when 5 to 10-cm-thick protective mortar covers had been set for 2 h. Experimental results from three-point loading tests of the panels indicated that the strain distributions measured from the two types of sensors were in good agreement, and cracks can be detected at sharp peaks of the measured strain distributions. The two-layer and three-layer coated fibers can be used to measure strains up to 2.33% and 2.42% with a corresponding sensitivity of 5.43×10-5 and 4.66×10-5 GHz/μɛ, respectively. Two cracks as close as 7 to 9 cm can be clearly detected. The measured strains in optical fiber were lower than the analytical prediction by 10% to 25%. Their difference likely resulted from strain transfer through various coatings, idealized point loading, varying optical fiber embedment, and concrete heterogeneity.

  19. [Further microbiological studies of the air in a newly built (under the pavement) section of the underground railway in Budapest].

    PubMed

    Szám, L; Vedres, I; Csatai, L; Nikodemusz, I

    1983-04-01

    In three subway stations, which are "sub-pavement" stations (Budapest), microbiological air analyses were simultaneously carried out by means of sedimentation and by the use of Krotow's impactor. In the course of the examinations, which lasted eight months, the following max. values were obtained on the agar plates: 78 colonies/dm2/h and 239 colonies/m3; the rates of incidence for pathogenic and indicator bacteria were 2.7 and 1.7 per 10 plates. The strongest airflow was 0.7 m/sec. These values were obtained at the "Nagy-várad tér" station, which forms a transition to the subway stations. The "stopper effect" was found to exist here as well, although not to such an extent as in the deep subway stations, but still more pronounced than in the other two "subpavement" stations "Esceri ut" and "Határ ut". The microbiological values are at any rate more favourable than in the subway stations dealt with in an earlier paper. PMID:6670402

  20. Optimisation structurale de dalles de chaussees en beton jointees avec des goujons en materiaux composites en Polymeres Renforces de Fibres de Verre (PRFV)

    NASA Astrophysics Data System (ADS)

    Bricola, Julien

    In Quebec, the majority of the road network was built in the 60's - 70's and show obvious signs of ageing. Moreover, the increase of road traffic and the rigorous weather conditions, render the maintenance and the exploitation of roads in this Northern American part quite difficult. Indeed, these environmental conditions cause severe damages for roads, especially in winter. The degradation factor of the jointed rigid pavement is intensified by the highway salt. So, the phenomena of deteriorations appears mainly by the corrosion of the steel at the joints (structural elements) guaranteeing the durability of roads. The jointed rigid pavements or "short jointed pavements" are still mainly sized with steel dowels placed at the lining of joints. One of the main functions of these structures is to control the formation of cracking due to the thermal and environmental conditions. In order to reduce these , disorders, the Ministry of Transport of Quebec (MTQ) turned towards new techniques and innovative materials to ensure the longevity of roads. With the rapid evolution of specific methods and knowledge in roads design, joined with technologies and new products, the MTQ emphasizes the research and development. That way, advanced techniques and diverse technologies in the Quebecois context are settled. As a matter of fact, one of the axes of these development researches concerns the composite materials which have recently been given good results in the civil engineering area. That is why Glass Fibre-Reinforced Polymer (GFRP) dowels bars appear as a solution to the steel corrosion. In fact, they provide better durability with lower costs: the increase of service life as well as the decrease of maintenance persons and traffics impac. Thus, this project proposes an optimization of structural design of GFRP dowels for transverse jointed highway pavement slabs, also keeping in mind their use in new projects. The GFRP dowels which are given in this essay are made by the Pultrall

  1. PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, Barbara J.

    2013-01-01

    Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin’s ban by analyzing PAHs in sediment cores and bottom-sediment samples collected in 1998, 2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving water body for Austin urban runoff. The sum concentration of the 16 EPA Priority Pollutant PAHs (∑PAH16) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998–2005 to 2006–2014 (means of 7980 and 4500 μg kg–1, respectively), and by 2012–2014, the decline was about 58% (mean of 3320 μg kg–1). Concentrations of ∑PAH16 in bottom sediment from two of three mid-lake sites decreased by about 71 and 35% from 2001 to 2014. Concentrations at a third site increased by about 14% from 2001 to 2014. The decreases since 2006 reverse a 40-year (1959–1998) upward trend. Despite declines in PAH concentrations, PAH profiles and source-receptor modeling results indicate that coal-tar sealants remain the largest PAH source to the lake, implying that PAH concentrations likely will continue to decline as stocks of previously applied sealant gradually become depleted.

  2. Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, Barbara J.

    2010-01-01

    Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) has increased in the United States during the past 40 years. We evaluated sources of PAHs in post-1990 sediments in cores from 40 lakes in urban areas across the United States using a contaminant mass-balance receptor model and including as a potential source coal-tar-based (CT) sealcoat, a recently recognized source of urban PAH. Other PAH sources considered included several coal- and vehicle-related sources, wood combustion, and fuel-oil combustion. The four best modeling scenarios all indicate CT sealcoat is the largest PAH source when averaged across all 40 lakes, contributing about one-half of PAH in sediment, followed by vehicle-related sources and coal combustion. PAH concentrations in the lakes were highly correlated with PAH loading from CT sealcoat (Spearman's rho=0.98), and the mean proportional PAH profile for the 40 lakes was highly correlated with the PAH profile for dust from CT-sealed pavement (r=0.95). PAH concentrations and mass and fractional loading from CT sealcoat were significantly greater in the central and eastern United States than in the western United States, reflecting regional differences in use of different sealcoat product types. The model was used to calculate temporal trends in PAH source contributions during the last 40 to 100 years to eight of the 40 lakes. In seven of the lakes, CT sealcoat has been the largest source of PAHs since the 1960s, and in six of those lakes PAH trends are upward. Traffic is the largest source to the eighth lake, located in southern California where use of CT sealcoat is rare.

  3. Evaluation of western shale-oil residue as an additive to petroleum asphalt for use as a pavement crack and joint sealant material

    SciTech Connect

    Harnsberger, P.M.; Wolf, J.M.; Robertson, R.E.

    1992-11-01

    The objective of this study was to perform a preliminary evaluation of using a distillation residue from Green River Formation (western) shale oil as an additive to a petroleum asphalt for use as a crack and joint filler material in portland cement concrete and asphaltic pavements. A commercially available rubberized asphalt crack and joint filler material was also tested for comparison. ASTM specification tests for sealant materials used in concrete and asphalt pavements were performed on the sealant materials. Portland cement concrete briquets prepared with an asphalt material sandwiched between two concrete wafers were tested in a stress-relaxation experiment to evaluate the relaxation and recovery properties of the sealant materials. The results show that the shale-oil modified petroleum asphalts and the neat petroleum asphalt do not pass the extension portion of the ASTM test; however, there is indication of improvement in the adhesive properties of the shale-oil modified asphalts. There is also evidence that the addition of shale-oil residue to the petroleum asphalt, especially at the 20% level, improves the relaxation and recovery properties compared with the petroleum asphalt.

  4. Estimation of in-situ density and moisture content in HMA pavements based on GPR trace reflection amplitude using different frequencies

    NASA Astrophysics Data System (ADS)

    Plati, Christina; Loizos, Andreas

    2013-10-01

    The basic goal of the present research is to investigate the estimation of both the in-situ density and moisture content within the Hot Mix Asphalt (HMA) pavement layer(s) in a non-destructive way using Ground Penetrating Radar (GPR) trace reflection amplitude. For this purpose, an extensive pavement survey was conducted using an air-coupled GPR system, operating at 1 GHz or alternatively with a 2 GHz central frequency. The collected data were analyzed comparatively for the two antennae. The variability of electric permittivity caused by variations in HMA material is discussed, while the effect of the different frequencies is compared on the ability to retrieve permittivity, in-situ density and moisture content of the compacted HMA material using relationships suggested in reviewed international literature. The main finding of the present research is that for the same type of HMA material, the assessment of the material properties appears to be independent from the two central frequencies of investigation. However, there is evidence concerning the variations between the GPR wave data for the two different frequencies. The

  5. Effects of composition and exposure on the solar reflectance of Portland cement concrete

    SciTech Connect

    Levinson, Ronnen; Akbari, Hashem

    2001-12-21

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Simulations of the influence of pavement albedo on air temperature in Los Angeles predict that increasing the albedo of 1,250 km2 of pavement by 0.25 would save cooling energy worth $15M yr-1, and reduce smog-related medical and lost-work expenses by $76M yr-1. Most sidewalks and a small fraction of roads and parking areas are paved with portland cement concrete, which can be made quite reflective through suitable choice of cement and aggregate. Variations with composition and environmental exposure of the albedos of portland cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Twenty-four mixes yielded substandard, ''rough'' concretes due to high, unmet aggregate water demand. The albedos of the remaining eight ''smooth'' concrete mixes ranged from 0.41 to 0.77 (mean 0.59). Simulated weathering, soiling, and abrasion each reduced average concrete albedo (mean decreases 0.06, 0.05, and 0.19, respectively), though some samples became slightly more reflective through weathering or soiling. Simulated rain (wetting) strongly depressed the albedos of concretes (mean decrease 0.23) until their surfaces were dried. Concrete albedo grew as the cement hydration reaction progressed (mean increase 0.08), but stabilized within six weeks of casting. White-cement concretes were on average significantly more reflective than gray-cement concretes. The albedo of the most-reflective white-cement concrete was 0.18 to 0.39 higher than that of the most-reflective gray-cement concrete, depending on state of exposure. Concrete albedo generally correlated with cement albedo and sand albedo, and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance of concrete. Efflorescence and surface

  6. Claudin 28b and F-actin are involved in rainbow trout gill pavement cell tight junction remodeling under osmotic stress.

    PubMed

    Sandbichler, Adolf Michael; Egg, Margit; Schwerte, Thorsten; Pelster, Bernd

    2011-05-01

    Permeability of rainbow trout gill pavement cells cultured on permeable supports (single seeded inserts) changes upon exposure to freshwater or treatment with cortisol. The molecular components of this change are largely unknown, but tight junctions that regulate the paracellular pathway are prime candidates in this adaptational process. Using differential display polymerase chain reaction we found a set of 17 differentially regulated genes in trout pavement cells that had been exposed to freshwater apically for 24 h. Five genes were related to the cell-cell contact. One of these genes was isolated and identified as encoding claudin 28b, an integral component of the tight junction. Immunohistochemical reactivity to claudin 28b protein was concentrated in a circumferential ring colocalized to the cortical F-actin ring. To study the contribution of this isoform to changes in transepithelial resistance and Phenol Red diffusion under apical hypo-or hyperosmotic exposure we quantified the fluorescence signal of this claudin isoform in immunohistochemical stainings together with the fluorescence of phalloidin-probed F-actin. Upon hypo-osmotic stress claudin 28b fluorescence and epithelial tightness remained stable. Under hyperosmotic stress, the presence of claudin 28b at the junction significantly decreased, and epithelial tightness was severely reduced. Cortical F-actin fluorescence increased upon hypo-osmotic stress, whereas hyperosmotic stress led to a separation of cortical F-actin rings and the number of apical crypt-like pores increased. Addition of cortisol to the basolateral medium attenuated cortical F-actin separation and pore formation during hyperosmotic stress and reduced claudin 28b in junctions except after recovery of cells from exposure to freshwater. Our results showed that short-term salinity stress response in cultured trout gill cells was dependent on a dynamic remodeling of tight junctions, which involves claudin 28b and the supporting F-actin ring

  7. Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line.

    PubMed

    Kienzler, Aude; Mahler, Barbara J; Van Metre, Peter C; Schweigert, Nathalie; Devaux, Alain; Bony, Sylvie

    2015-07-01

    Coal-tar-based (CTB) sealcoat, frequently applied to parking lots and driveways in North America, contains elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and related compounds. The RTL-W1 fish liver cell line was used to investigate two endpoints (genotoxicity and DNA-repair-capacity impairment) associated with exposure to runoff from asphalt pavement with CTB sealcoat or with an asphalt-based sealcoat hypothesized to contain about 7% CTB sealcoat (AS-blend). Genotoxic potential was assessed by the Formamido pyrimidine glycosylase (Fpg)-modified comet assay for 1:10 and 1:100 dilutions of runoff samples collected from 5 h to 36 d following sealcoat application. DNA-repair capacity was assessed by the base excision repair comet assay for 1:10 dilution of samples collected 26 h and 36 d following application. Both assays were run with and without co-exposure to ultraviolet-A radiation (UVA). With co-exposure to UVA, genotoxic effects were significant for both dilutions of CTB runoff for three of four sample times, and for some samples of AS-blend runoff. Base excision repair was significantly impaired for CTB runoff both with and without UVA exposure, and for AS-blend runoff only in the absence of UVA. This study is the first to investigate the effects of exposure to the complex mixture of chemicals in coal tar on DNA repair capacity. The results indicate that co-exposure to runoff from CT-sealcoated pavement and UVA as much as a month after sealcoat application has the potential to cause genotoxicity and impair DNA repair capacity. PMID:25795989

  8. Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line

    USGS Publications Warehouse

    Kienzler, Aude; Mahler, Barbara J.; Van Metre, Peter C.; Schweigert, Nathalie; Devaux, Alain; Bony, Sylvie

    2015-01-01

    Coal-tar-based (CTB) sealcoat, frequently applied to parking lots and driveways in North America, contains elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and related compounds. The RTL-W1 fish liver cell line was used to investigate two endpoints (genotoxicity and DNA-repair-capacity impairment) associated with exposure to runoff from asphalt pavement with CTB sealcoat or with an asphalt-based sealcoat hypothesized to contain about 7% CTB sealcoat (AS-blend). Genotoxic potential was assessed by the Formamido pyrimidine glycosylase (Fpg)-modified comet assay for 1:10 and 1:100 dilutions of runoff samples collected from 5 h to 36 d following sealcoat application. DNA-repair capacity was assessed by the base excision repair comet assay for 1:10 dilution of samples collected 26 h and 36 d following application. Both assays were run with and without co-exposure to ultraviolet-A radiation (UVA). With co-exposure to UVA, genotoxic effects were significant for both dilutions of CTB runoff for three of four sample times, and for some samples of AS-blend runoff. Base excision repair was significantly impaired for CTB runoff both with and without UVA exposure, and for AS-blend runoff only in the absence of UVA. This study is the first to investigate the effects of exposure to the complex mixture of chemicals in coal tar on DNA repair capacity. The results indicate that co-exposure to runoff from CT-sealcoated pavement and UVA as much as a month after sealcoat application has the potential to cause genotoxicity and impair DNA repair capacity.

  9. Electrocatalyst compositions

    DOEpatents

    Mallouk, Thomas E.; Chan, Benny C.; Reddington, Erik; Sapienza, Anthony; Chen, Guoying; Smotkin, Eugene; Gurau, Bogdan; Viswanathan, Rameshkrishnan; Liu, Renxuan

    2001-09-04

    Compositions for use as catalysts in electrochemical reactions are described. The compositions are alloys prepared from two or more elemental metals selected from platinum, molybdenum, osmium, ruthenium, rhodium, and iridium. Also described are electrode compositions including such alloys and electrochemical reaction devices including such catalysts.

  10. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

  11. Composites review

    NASA Technical Reports Server (NTRS)

    Hordonneau, A.

    1987-01-01

    The properties and applications of composite materials are reviewed. Glass, carbon, Kevlar, ceramic, whisker, and metal fibers are discussed along with polyester, epoxy, polyimide, Peek, carbon, ceramic, and metal matrices. The quantitative distribution of high technology fiber in various applications is given. The role of aerospace industry in the development and promotion of composite utilization is discussed. Consumption trends indicate a rapid development of the composite market.

  12. Energetic composites

    DOEpatents

    Danen, Wayne C.; Martin, Joe A.

    1993-01-01

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

  13. Energetic composites

    DOEpatents

    Danen, W.C.; Martin, J.A.

    1993-11-30

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application. 3 figures.

  14. Composite floorpan

    SciTech Connect

    Frutiger, R.L.; Baskar, S.

    1993-02-01

    Composite applications for automotive components have been a topic of increased interest. Some applications--load-bearing composites such as bumpers and leaf springs--have been implemented successfully in production vehicles. On the other hand, semi-structural load-bearing composites such as floorpans have not been investigated as extensively for stiffness, strength, and durability. Past studies have used structural composites to achieve parts consolidation in van crossmembers. A rear floorpan has also been demonstrated in composites. A hybrid vehicle structure consisting of a composite passenger module on a steel frame has been proposed. Assessments of the energy management of full composite front structures have also been reported. There remains a need to assess structural composites for a major load-bearing panel with real-vehicle packaging and design requirements; a floorplan is one such application. This design concept might be used in a space-frame vehicle structure in which composite panels could be used to complete the structure and provide additional torsional rigidity while meeting local strength and stiffness requirements.

  15. Electrode compositions

    DOEpatents

    Block, J.; Fan, X.

    1998-10-27

    An electrode composition is described for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C{sub 8}-C{sub 15} alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5--4.5 volts.

  16. Electrode compositions

    DOEpatents

    Block, Jacob; Fan, Xiyun

    1998-01-01

    An electrode composition for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C.sub.8 -C.sub.15 alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5-4.5 volts.

  17. Traffic generated non-exhaust particulate emissions from concrete pavement: A mass and particle size study for two-wheelers and small cars

    NASA Astrophysics Data System (ADS)

    Aatmeeyata; Kaul, D. S.; Sharma, Mukesh

    This study aimed to understand the non-exhaust (NE) emission of particles from wear of summer tire and concrete pavement, especially for two wheelers and small cars. A fully enclosed laboratory-scale model was fabricated to simulate road tire interaction with a facility to collect particles in different sizes. A road was cast using the M-45 concrete mixture and the centrifugal casting method. It was observed that emission of large particle non exhaust emission (LPNE) as well as PM 10 and PM 2.5 increased with increasing load. The LPNE was 3.5 mg tire -1 km -1 for a two wheeler and 6.4 mg tire -1 km -1 for a small car. The LPNE can lead to water pollution through water run-off from the roads. The contribution of the PM 10 and PM 2.5 was smaller compared to the LPNE particles (less than 0.1%). About 32 percent of particle mass of PM 10 was present below 1 μm. The number as well as mass size distribution for PM 10 was observed to be bi-modal with peaks at 0.3 μm and 4-5 μm. The NE emissions did not show any significant trend with change in tire pressure.

  18. TYPE-ONE PROTEIN PHOSPHATASE4 Regulates Pavement Cell Interdigitation by Modulating PIN-FORMED1 Polarity and Trafficking in Arabidopsis1

    PubMed Central

    Guo, Xiaola; Qin, Qianqian; Yan, Jia; Niu, Yali; Huang, Bingyao; Guan, Liping; Li, Yuan; Ren, Dongtao; Li, Jia; Hou, Suiwen

    2015-01-01

    In plants, cell morphogenesis is dependent on intercellular auxin accumulation. The polar subcellular localization of the PIN-FORMED (PIN) protein is crucial for this process. Previous studies have shown that the protein kinase PINOID (PID) and protein phosphatase6-type phosphatase holoenzyme regulate the phosphorylation status of PIN1 in root tips and shoot apices. Here, we show that a type-one protein phosphatase, TOPP4, is essential for the formation of interdigitated pavement cell (PC) pattern in Arabidopsis (Arabidopsis thaliana) leaf. The dominant-negative mutant topp4-1 showed severely inhibited interdigitated PC growth. Expression of topp4-1 gene in wild-type plants recapitulated the PC defects in the mutant. Genetic analyses suggested that TOPP4 and PIN1 likely function in the same pathway to regulate PC morphogenesis. Furthermore, colocalization, in vitro and in vivo protein interaction studies, and dephosphorylation assays revealed that TOPP4 mediated PIN1 polar localization and endocytic trafficking in PCs by acting antagonistically with PID to modulate the phosphorylation status of PIN1. In addition, TOPP4 affects the cytoskeleton pattern through the Rho of Plant GTPase-dependent auxin-signaling pathway. Therefore, we conclude that TOPP4-regulated PIN1 polar targeting through direct dephosphorylation is crucial for PC morphogenesis in the Arabidopsis leaf. PMID:25560878

  19. Comparing Composites.

    ERIC Educational Resources Information Center

    Mathras, Michael S.

    1993-01-01

    Presents an activity that models the work of chemical engineers. Students design, fabricate, and perform mechanical tests on plaster matrix composites and compare the strength to mass ratios of several products. (PR)

  20. Fuel composition

    SciTech Connect

    Johnson, T.H.

    1990-06-26

    This patent describes a motor fuel composition. It comprises: a mixture of hydrocarbons in the gasoline boiling range containing a deposit preventing or reducing effective amount of poly(olefin)-N-substituted- carbamate.

  1. Hydride compositions

    DOEpatents

    Lee, Myung W.

    1995-01-01

    A composition for use in storing hydrogen, and a method for making the composition. The composition comprises a mixture of two or more hydrides, each hydride having a different series of hydrogen sorption isotherms that contribute to the overall isotherms of the mixture. The hydrides are chosen so that the isotherms of the mixture have regions wherein the hydrogen equilibrium pressure increases with increasing hydrogen, preferably linearly. The isotherms of the mixture can be adjusted by selecting hydrides with different isotherms and by varying the amounts of the individual hydrides, or both. Preferably, the mixture is made up of hydrides that have isotherms with substantially flat plateaus and in nearly equimolar amounts. The composition is activated by degassing, exposing to hydrogen and then heating at a temperature below the softening temperature of any of the. constituents so that their chemical and structural integrity is preserved. When the composition is used to store hydrogen, its hydrogen content can be found simply by measuring P.sub.H.sbsb.2 and determining H/M from the isothermic function of the composition.

  2. Hydride compositions

    DOEpatents

    Lee, Myung, W.

    1994-01-01

    Disclosed are a composition for use in storing hydrogen and a method for making the composition. The composition comprises a mixture of two or more hydrides, each hydride having a different series of hydrogen sorption isotherms that contribute to the overall isotherms of the mixture. The hydrides are chosen so that the isotherms of the mixture have regions wherein the H equilibrium pressure increases with increasing hydrogen, preferably linearly. The isotherms of the mixture can be adjusted by selecting hydrides with different isotherms and by varying the amounts of the individual hydrides, or both. Preferably, the mixture is made up of hydrides that have isotherms with substantially flat plateaus and in nearly equimolar amounts. The composition is activated by degassing, exposing to H, and then heating below the softening temperature of any of the constituents. When the composition is used to store hydrogen, its hydrogen content can be found simply by measuring P{sub H}{sub 2} and determining H/M from the isothermic function of the composition.

  3. Photoimageable composition

    DOEpatents

    Dentinger, Paul; Krafick, Karen L.; Simison, Kelby Liv

    2005-02-22

    The use of photoacid generators including an alkoxyphenylphenyliodonium salt and/or bis(t-butylphenyl)iodonium salt in a photoimageable composition helps improve resolution. Suitable photoimageable compositions includes: (a) a multifuctional polymeric epoxy resin that is dissolved in an organic solvent wherein the epoxy resin comprises oligomers of bisphenol A that is quantitatively protected by glycidyl ether and wherein the oligomers have an average functionality that ranges from about 3 to 12; and a photoacid generator comprising an alkoxyphenylphenyliodonium salt and/or bis(t-butylphenyl)iodonium salt. Preferred alkoxyphenylphenyliodonium salts include 4-octyloxyphenyl phenyliodonium hexafluoroantimonate and 4-methoxyphenyl phenyliodonium hexafluoroantimonate. The photoimageable composition is particularly suited for producing high aspect ratio microstructures.

  4. Photoimageable composition

    DOEpatents

    Simison, Kelby Liv; Dentinger, Paul

    2003-11-11

    The use of selected buffering amines in a photoimageable composition prevents process bias which with conventional photoresists causes designed features to be distorted, especially in corners and high resolution features. It is believed that the amines react with the catalysts, e.g., photoacids, generated to create an inert salt. The presence of the amines also increases resolution. Suitable photoimageable compositions includes: (a) a multifunctional polymeric epoxy resin that is dissolved in an organic solvent wherein the epoxy resin comprises oligomers of bisphenol A that is quantitatively protected by glycidyl ether and wherein the oligomers have an average functionality that ranges from about 3 to 12; (b) a photoactive compound; and (c) an amine that is selected from the group consisting of triisobutylamine, 1,8-bis(dimethylamino)naphthalene (also known as PROTON SPONGET.TM.), 2,2'-diazabicyclo[2.2.2] octane and mixtures thereof. The photoimageable composition is particularly suited for producing high aspect ratio metal microstructures.

  5. Composite material

    DOEpatents

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  6. Surfactant compositions

    SciTech Connect

    Novakovic, M.; Abend, P.G.

    1987-09-29

    A surfactant composition is described for subsequent addition to a soap slurring comprising an acyloxy alkane sulfonate salt. The sulfonate salt is present in an amount by weight of about 44 percent of about 56 percent. The polyol is present in an amount by weight of about 2 percent to about 6 percent, and water is present in an amount by weight of 26 to 36 percent. The composition constituting a solid reversible solution at ambient temperature and having a solids content of about 58 to 72 percent, whereby subsequent addition of the surfactant composition to a soap slurry results in formation of a soap/detergent bar having a smooth texture, uniform wear properties and a lack of grittiness.

  7. Physical composition

    NASA Astrophysics Data System (ADS)

    Healey, Richard

    2013-02-01

    Atomistic metaphysics motivated an explanatory strategy which science has pursued with great success since the scientific revolution. By decomposing matter into its atomic and subatomic parts physics gave us powerful explanations and accurate predictions as well as providing a unifying framework for the rest of science. The success of the decompositional strategy has encouraged a widespread conviction that the physical world forms a compositional hierarchy that physics and other sciences are progressively articulating. But this conviction does not stand up to a closer examination of how physics has treated composition, as a variety of case studies will show.

  8. Composite Riflescope

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Bushnell Division of Bausch & Lomb's Armor-Sight riflescope combines the company's world-renowned optics with a graphite composite (Graphlon VI) developed for space applications. The riflescope is 10 percent lighter than aluminum scopes, and, because its thermal expansion coefficient is near zero, optical distortion from heat and cold extremes is eliminated. It is fogproof and waterproof; advanced multicoated optics provide maximum light transmission to brighten target ranges. Bushnell was assisted by NIAC/USC in searching for technical information on graphic composites and in overcoming difficulties with bonding and porosity.

  9. Composite Cores

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Spang & Company's new configuration of converter transformer cores is a composite of gapped and ungapped cores assembled together in concentric relationship. The net effect of the composite design is to combine the protection from saturation offered by the gapped core with the lower magnetizing requirement of the ungapped core. The uncut core functions under normal operating conditions and the cut core takes over during abnormal operation to prevent power surges and their potentially destructive effect on transistors. Principal customers are aerospace and defense manufacturers. Cores also have applicability in commercial products where precise power regulation is required, as in the power supplies for large mainframe computers.

  10. Myosins XI-K, XI-1, and XI-2 are required for development of pavement cells, trichomes, and stigmatic papillae in Arabidopsis

    PubMed Central

    2012-01-01

    Background The positioning and dynamics of vesicles and organelles, and thus the growth of plant cells, is mediated by the acto-myosin system. In Arabidopsis there are 13 class XI myosins which mediate vesicle and organelle transport in different cell types. So far the involvement of five class XI myosins in cell expansion during the shoot and root development has been shown, three of which, XI-1, XI-2, and XI-K, are essential for organelle transport. Results Simultaneous depletion of Arabidopsis class XI myosins XI-K, XI-1, and XI-2 in double and triple mutant plants affected the growth of several types of epidermal cells. The size and shape of trichomes, leaf pavement cells and the elongation of the stigmatic papillae of double and triple mutant plants were affected to different extent. Reduced cell size led to significant size reduction of shoot organs in the case of triple mutant, affecting bolt formation, flowering time and fertility. Phenotype analysis revealed that the reduced fertility of triple mutant plants was caused by delayed or insufficient development of pistils. Conclusions We conclude that the class XI myosins XI-K, XI-1 and XI-2 have partially redundant roles in the growth of shoot epidermis. Myosin XI-K plays more important role whereas myosins XI-1 and XI-2 have minor roles in the determination of size and shape of epidermal cells, because the absence of these two myosins is compensated by XI-K. Co-operation between myosins XI-K and XI-2 appears to play an important role in these processes. PMID:22672737

  11. The Apache Longbow-Hellfire Missile Test at Yuma Proving Ground: Ecological Risk Assessment for Tracked Vehicle Movement across Desert Pavement

    SciTech Connect

    Peterson, Mark J; Efroymson, Rebecca Ann; Hargrove, William Walter

    2008-01-01

    A multiple stressor risk assessment was conducted at Yuma Proving Ground, Arizona, as a demonstration of the Military Ecological Risk Assessment Framework. The focus was a testing program at Cibola Range, which involved an Apache Longbow helicopter firing Hellfire missiles at moving targets, M60-A1 tanks. This paper describes the ecological risk assessment for the tracked vehicle movement component of the testing program. The principal stressor associated with tracked vehicle movement was soil disturbance, and a resulting, secondary stressor was hydrological change. Water loss to washes and wash vegetation was expected to result from increased infiltration and/or evaporation associated with disturbances to desert pavement. The simulated exposure of wash vegetation to water loss was quantified using estimates of exposed land area from a digital ortho quarter quad aerial photo and field observations, a 30 30 m digital elevation model, the flow accumulation feature of ESRI ArcInfo, and a two-step process in which runoff was estimated from direct precipitation to a land area and from water that flowed from upgradient to a land area. In all simulated scenarios, absolute water loss decreased with distance from the disturbance, downgradient in the washes; however, percentage water loss was greatest in land areas immediately downgradient of a disturbance. Potential effects on growth and survival of wash trees were quantified by using an empirical relationship derived from a local unpublished study of water infiltration rates. The risk characterization concluded that neither risk to wash vegetation growth or survival nor risk to mule deer abundance and reproduction was expected. The risk characterization was negative for both the incremental risk of the test program and the combination of the test and pretest disturbances.

  12. Analysis of a Spatial Point Pattern: Examining the Damage to Pavement and Pipes in Santa Clara Valley Resulting from the Loma Prieta Earthquake

    USGS Publications Warehouse

    Phelps, G.A.

    2008-01-01

    This report describes some simple spatial statistical methods to explore the relationships of scattered points to geologic or other features, represented by points, lines, or areas. It also describes statistical methods to search for linear trends and clustered patterns within the scattered point data. Scattered points are often contained within irregularly shaped study areas, necessitating the use of methods largely unexplored in the point pattern literature. The methods take advantage of the power of modern GIS toolkits to numerically approximate the null hypothesis of randomly located data within an irregular study area. Observed distributions can then be compared with the null distribution of a set of randomly located points. The methods are non-parametric and are applicable to irregularly shaped study areas. Patterns within the point data are examined by comparing the distribution of the orientation of the set of vectors defined by each pair of points within the data with the equivalent distribution for a random set of points within the study area. A simple model is proposed to describe linear or clustered structure within scattered data. A scattered data set of damage to pavement and pipes, recorded after the 1989 Loma Prieta earthquake, is used as an example to demonstrate the analytical techniques. The damage is found to be preferentially located nearer a set of mapped lineaments than randomly scattered damage, suggesting range-front faulting along the base of the Santa Cruz Mountains is related to both the earthquake damage and the mapped lineaments. The damage also exhibit two non-random patterns: a single cluster of damage centered in the town of Los Gatos, California, and a linear alignment of damage along the range front of the Santa Cruz Mountains, California. The linear alignment of damage is strongest between 45? and 50? northwest. This agrees well with the mean trend of the mapped lineaments, measured as 49? northwest.

  13. COMPOSITE ELEMENT

    DOEpatents

    Schaner, B.E.; Wolfe, R.A.

    1962-12-18

    Composite fuel eiements of the sandwich type are reported. The invention resides in the use of a layer of graphite on the interfaces of the flssile material and the cladding to prevent interdiffusion of the fissile material and the ciadding material. (AEC)

  14. Music Composition

    ERIC Educational Resources Information Center

    Helfer, Jason A.

    2015-01-01

    Historically, music programs in K-12 schools have emphasized performance opportunities for children and young people. Until the release of the 1994 National Standards in Music, targeted instruction in composition was frequently overlooked due to the emphasis on performance as well as the expectations of what a school music program ought to produce…

  15. Phosphorescent compositions, methods of making the compositions, and methods of using the compositions

    DOEpatents

    Jia, Weiyi; Wang, Xiaojun; Jia, George D.; Lewis, Linda; Yen, Laurel C.

    2014-06-24

    Compositions, methods of making compositions, materials including compositions, crayons including compositions, paint including compositions, ink including compositions, waxes including compositions, polymers including compositions, vesicles including the compositions, methods of making each, and the like are disclosed.

  16. Phosphorescent compositions, methods of making the compositions, and methods of using the compositions

    DOEpatents

    Jia, Weiyi; Wang, Xiaojun; Yen, William; Yen, Laurel C.; Jia, George D.

    2012-12-04

    Compositions, methods of making compositions, materials including compositions, crayons including compositions, paint including compositions, ink including compositions, waxes including compositions, polymers including compositions, vesicles including the compositions, methods of making each, and the like are disclosed.

  17. Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

    NASA Astrophysics Data System (ADS)

    Loh, Kenneth J.; Gonzalez, Jesus

    2015-07-01

    Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens.

  18. Pb, Sr and Nd isotopic composition and trace element characteristics of coarse airborne particles collected with passive samplers

    NASA Astrophysics Data System (ADS)

    Hoàng-Hòa, Thi Bich; Stille, Peter; Dietze, Volker; Guéguen, Florence; Perrone, Thierry; Gieré, Reto

    2015-09-01

    Passive samplers for collection of coarse airborne particulate matter have been installed in and around the coal-mining town of Cam Pha, Quang Ninh Province (Vietnam). Analysis of Pb, Sr, and Nd isotope ratios and of major and trace element distribution patterns in atmospheric particulates collected at three stations allowed for the identification of four important dust components: (1) coal dust from an open-pit mine and fly ash particles from a coal-fired power station, (2) diesel soot, (3) traffic dust from metal, tire and pavement abrasion, and (4) limestone-derived dust. Outside of the coal-mining area, traffic-derived dust defines the atmospheric baseline composition of the studied environment.

  19. Strain distribution in thin concrete pavement panels under three-point loading to failure with pre-pulse-pump Brillouin optical time domain analysis (Presentation Video)

    NASA Astrophysics Data System (ADS)

    Bao, Yi; Cain, John; Chen, Yizheng; Huang, Ying; Chen, Genda; Palek, Leonard

    2015-04-01

    three types of fibers were functional until the concrete panels have experienced inelastic deformation, making the distributed strain sensing technology promising for real applications in pavement engineering.

  20. Concrete compositions and methods

    SciTech Connect

    Chen, Irvin; Lee, Patricia Tung; Patterson, Joshua

    2015-06-23

    Provided herein are compositions, methods, and systems for cementitious compositions containing calcium carbonate compositions and aggregate. The compositions find use in a variety of applications, including use in a variety of building materials and building applications.

  1. ) Hybrid Composite

    NASA Astrophysics Data System (ADS)

    Show, Bijay Kumar; Mondal, Dipak Kumar; Maity, Joydeep

    2014-12-01

    In this research work, the dry sliding wear behavior of 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite was investigated at low sliding speed (1 m/s) against a hardened EN 31 disk at different loads. In general, the wear mechanism involved adhesion (along with associated subsurface cracking and delamination) and microcutting abrasion at lower load. While at higher load, abrasive wear involving microcutting and microploughing along with adherent oxide formation was observed. The overall wear rate increased with increasing normal load. The massive particle clusters as well as individual reinforcement particles were found to stand tall to resist abrasive wear. Besides, at higher load, the generation of adherent nodular tribo-oxide through nucleation and epitaxial growth on existing Al2O3 particles lowered down the wear rate. Accordingly, at any normal load, 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite exhibited superior wear resistance (lower overall wear rate) than the reported wear resistance of monolithic 6351 Al alloy.

  2. Composite Tank

    NASA Technical Reports Server (NTRS)

    DeLay, Thomas K. (Inventor)

    2000-01-01

    A composite tank for containing liquid oxygen and the method of making the same Wherein a water-soluble mandrel having ing the desired tank configuration and a cylindrical protuberance on at least one end is fitted with an inner boss conformance, to the configuration of the mandrel and in outer boss conforming to the configuration of the inner boss, the bosses each having a tubular portion for receiving the protuberance on the mandrel and a spherical portion. The mandrel and the bosses are first coated with a nickel coating. The mandrel is then wrapped with graphite fibers wetted with an epoxy resin and this resin is cured. A layer of insulating foam is then applied to the tank and cured. The insulating foam is machined to a desired concentration and a layer of aramid fibers wetted with a second epoxy resin is wrapped around the tank. The second resin is cured and the water soluble mandrel is washed from inside the tank.

  3. Composite foams

    DOEpatents

    Williams, Jr., Joel M.; Nyitray, Alice M.; Wilkerson, Mark H.

    1990-01-01

    Composite foams are provided comprising a first rigid, microcellular, open-celled organic polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 1 micron to about 30 microns, said first foam containing a second polymer having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 or a second polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 0.01 microns to about 1.0 micron within the open cells of said first foam.

  4. Composite foams

    DOEpatents

    Williams, Jr., Joel M.; Nyitray, Alice M.; Wilkerson, Mark H.

    1991-01-01

    Composite foams are provided comprising a first rigid, microcellular, open-celled organic polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 1 micron to about 30 microns, said first foam containing a second polymer having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 or a second polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 0.01 microns to about 1.0 micron within the open cells of said first foam.

  5. Breaks in Pavement and Pipes as Indicators of Range-Front Faulting Resulting from the 1989 Loma Prieta Earthquake near the Southwest Margin of the Santa Clara Valley, California

    USGS Publications Warehouse

    Schmidt, Kevin M.; Ellen, Stephen D.; Haugerud, Ralph A.; Peterson, David M.; Phelps, Geoffery A.

    1995-01-01

    Damage to pavement and near-surface utility pipes, caused by the October 17, 1989, Loma Prieta earthquake, provide indicators for ground deformation in a 663 km2 area near the southwest margin of the Santa Clara Valley, California. The spatial distribution of 1284 sites of such damage documents the extent and distribution of detectable ground deformation. Damage was concentrated in four zones, three of which are near previously mapped faults. The zone through Los Gatos showed the highest concentration of damage, as well as evidence for pre- and post-earthquake deformation. Damage along the foot of the Santa Cruz Mountains reflected shortening that is consistent with movement along reverse faults in the region and with the hypothesis that tectonic strain is distributed widely across numerous faults in the California Coast Ranges.

  6. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  7. Fatigue of composites

    NASA Technical Reports Server (NTRS)

    Salkind, M. J.

    1972-01-01

    The failure mechanisms in the fatigue of composite materials are analyzed in terms of the requirements for designing fatigue-critical composite structures. Fiber reinforced polymers, fiber reinforced metals, fatigue of composite structures, and composite design considerations are discussed. It is concluded that composite materials offer the engineer the opportunity for tailoring stiffness in different directions for designing dynamic components.

  8. Composite powder particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald S. (Inventor); MacDowell, Louis G. (Inventor)

    2009-01-01

    A liquid coating composition including a coating vehicle and composite powder particles disposed within the coating vehicle. Each composite powder particle may include a magnesium component, a zinc component, and an indium component.

  9. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R. G.; Wiberley, S. E.

    1985-01-01

    Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.

  10. Conducting Compositions of Matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    1999-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  11. Conducting compositions of matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    2000-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  12. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1983-01-01

    Transverse properties of fiber constituents in composites, fatigue in composite materials, matrix dominated properties of high performance composites, numerical investigation of moisture effects, numerical investigation of the micromechanics of composite fracture, advanced analysis methods, compact lug design, and the RP-1 and RP-2 sailplanes projects are discussed.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

  14. Tough Composite Materials

    NASA Technical Reports Server (NTRS)

    Vosteen, L. F. (Compiler); Johnson, N. J. (Compiler); Teichman, L. A. (Compiler)

    1984-01-01

    Papers and working group summaries are presented which address composite material behavior and performance improvement. Topic areas include composite fracture toughness and impact characterization, constituent properties and interrelationships, and matrix synthesis and characterization.

  15. Carbon Fibers and Composites

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1979-01-01

    The basic nature of composite materials is considered. Carbon fiber composites and their area of current and planned application in civil aircraft are discussed, specifically within the framework of the various aspects of risk analysis.

  16. ACEE composite structures technology

    NASA Technical Reports Server (NTRS)

    Quinlivan, John T.; Wilson, Robert D.; Smith, Peter J.; Johnson, Ronald W.

    1984-01-01

    Toppics addressed include: advanced composites on Boeing commercial aircraft; composite wing durability; damage tolerance technology development; heavily loaded wing panel design; and pressure containment and damage tolerance in fuselages.

  17. Design of electronic composites

    SciTech Connect

    Taya, M.

    1995-12-31

    This report describes the requirements of selected electronic composites with application to electronic packaging, then focuses on the modeling for the microstructure-macrobehavior relation of electronic composites. The modeling depends on the microstructure, percolative and non-percolative.

  18. Heteroporphyrin nanotubes and composites

    DOEpatents

    Shelnutt, John A.; Medforth, Craig J.; Wang, Zhongchun

    2007-05-29

    Heteroporphyrin nanotubes, metal nanostructures, and metal/porphyrin-nanotube composite nanostructures formed using the nanotubes as photocatalysts and structural templates, and the methods for forming the nanotubes and composites.

  19. Heteroporphyrin nanotubes and composites

    DOEpatents

    Shelnutt, John A.; Medforth, Craig J.; Wang, Zhongchun

    2006-11-07

    Heteroporphyrin nanotubes, metal nanostructures, and metal/porphyrin-nanotube composite nanostructures formed using the nanotubes as photocatalysts and structural templates, and the methods for forming the nanotubes and composites.

  20. Thermoset molecular composites

    DOEpatents

    Benicewicz, Brian C.; Douglas, Elliot P.; Hjelm, Jr., Rex P.

    1996-01-01

    A polymeric composition including a liquid crystalline polymer and a thermosettable liquid crystalline monomer matrix, said polymeric composition characterized by a phase separation on the scale of less than about 500 Angstroms and a polymeric composition including a liquid crystalline polymer and a liquid crystalline thermoset matrix, said polymeric composition characterized by a phase separation on the scale of less than about 500 Angstroms are disclosed.

  1. Amorphous metal composites

    DOEpatents

    Byrne, Martin A.; Lupinski, John H.

    1984-01-01

    An improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite.

  2. Composite fuel cell membranes

    DOEpatents

    Plowman, Keith R.; Rehg, Timothy J.; Davis, Larry W.; Carl, William P.; Cisar, Alan J.; Eastland, Charles S.

    1997-01-01

    A bilayer or trilayer composite ion exchange membrane suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

  3. Nano-composite materials

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  4. Composite fuel cell membranes

    DOEpatents

    Plowman, K.R.; Rehg, T.J.; Davis, L.W.; Carl, W.P.; Cisar, A.J.; Eastland, C.S.

    1997-08-05

    A bilayer or trilayer composite ion exchange membrane is described suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

  5. Infiltrated carbon foam composites

    NASA Technical Reports Server (NTRS)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  6. Advanced composites for windmills

    NASA Astrophysics Data System (ADS)

    Bourquardez, G.

    A development status assessment is conducted for advanced composite construction techniques for windmill blade structures which, as in the case of composite helicopter rotors, promise greater reliability, longer service life, superior performance, and lower costs. Composites in wind turbine applications must bear aerodynamic, inertial and gravitational loads in complex interaction cycles. Attention is given to large Darrieus-type vertical axis windmills, to which composite construction methods may offer highly effective pitch-control mechanisms, especially in the 'umbrella' configuration.

  7. Solid polymer electrolyte compositions

    DOEpatents

    Garbe, James E.; Atanasoski, Radoslav; Hamrock, Steven J.; Le, Dinh Ba

    2001-01-01

    An electrolyte composition is featured that includes a solid, ionically conductive polymer, organically modified oxide particles that include organic groups covalently bonded to the oxide particles, and an alkali metal salt. The electrolyte composition is free of lithiated zeolite. The invention also features cells that incorporate the electrolyte composition.

  8. Phase change compositions

    DOEpatents

    Salyer, Ival O.

    1989-01-01

    Compositions containing crystalline, straight chain, alkyl hydrocarbons as phase change materials including cementitious compositions containing the alkyl hydrocarbons neat or in pellets or granules formed by incorporating the alkyl hydrocarbons in polymers or rubbers; and polymeric or elastomeric compositions containing alkyl hydrocarbons.

  9. Phase change compositions

    DOEpatents

    Salyer, Ival O.; Griffen, Charles W.

    1986-01-01

    Compositions containing crystalline, long chain, alkyl hydrocarbons as phase change materials including cementitious compositions containing the alkyl hydrocarbons neat or in pellets or granules formed by incorporating the alkyl hydrocarbons in polymers or rubbers; and polymeric or elastomeric compositions containing alkyl hydrocarbons.

  10. Metal etching composition

    NASA Technical Reports Server (NTRS)

    Otousa, Joseph E. (Inventor); Thomas, Clark S. (Inventor); Foster, Robert E. (Inventor)

    1991-01-01

    The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection.

  11. Refiguring Composition through Theory

    ERIC Educational Resources Information Center

    Lynch-Biniek, Amy

    2009-01-01

    In this dissertation, I argue that curricular choices in Composition are overdetermined by the academic labor system and its negative effect on the status of composition theory. Despite the growth of disciplinary knowledge, composition programs are still staffed largely with underpaid and under supported faculty and graduate students, many of whom…

  12. Composite Golf Clubs

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Babcock & Wilcox Co. under a partnership with Marshall Space Flight Center, produced composite materials, originally from the shuttle program, for improving golf clubs. Company used Marshall Space Flight Center's data summary file summarizing typical processing techniques and mechanical and physical properties of graphite and boron- reinforced composite materials. Reinforced composites provide combination of shaft rigidity and flexibility that provide maximum distance.

  13. ACEE composite structures technology

    NASA Technical Reports Server (NTRS)

    Klotzsche, M. (Compiler)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program has made significant progress in the development of technology for advanced composites in commercial aircraft. Commercial airframe manufacturers have demonstrated technology readiness and cost effectiveness of advanced composites for secondary and medium primary components and have initiated a concerted program to develop the data base required for efficient application to safety-of-flight wing and fuselage structures. Oral presentations were compiled into five papers. Topics addressed include: damage tolerance and failsafe testing of composite vertical stabilizer; optimization of composite multi-row bolted joints; large wing joint demonstation components; and joints and cutouts in fuselage structure.

  14. Developing composite signatures

    NASA Astrophysics Data System (ADS)

    Hawley, Chadwick T.; Carpenter, Tom; Cappelaere, Patrice G.; Frye, Stu; Lemoigne-Stewart, Jacqueline J.; Mandle, Dan; Montgomery, Sarah; Williams-Bess, Autumn

    2011-06-01

    A composite signature is a group of signatures that are related in such a way to more completely or further define a target or operational endeavor at a higher fidelity. This paper explores the merits of using composite signatures, in lieu of waiting for opportunities for the more elusive diagnostic signatures, to satisfy key essential elements of information Keywords: signature, composite signature, civil disaster (EEI) associated with civil disaster-related problems. It discusses efforts to refine composite signature development methodology and quantify the relative value of composite vs. diagnostic signatures. The objectives are to: 1) investigate and develop innovative composite signatures associated with civil disasters, including physical, chemical and pattern/behavioral; 2) explore the feasibility of collecting representative composite signatures using current and emerging intelligence, surveillance, and reconnaissance (ISR) collection architectures leveraging civilian and commercial architectures; and 3) collaborate extensively with scientists and engineers from U.S. government organizations and laboratories, the defense industry, and academic institutions.

  15. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1984-01-01

    Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

  16. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1987-01-01

    The development and application of composite materials to aerospace vehicle structures which began in the mid 1960's has now progressed to the point where what can be considered entire airframes are being designed and built using composites. Issues related to the fabrication of non-resin matrix composites and the micro, mezzo and macromechanics of thermoplastic and metal matrix composites are emphasized. Several research efforts are presented. They are entitled: (1) The effects of chemical vapor deposition and thermal treatments on the properties of pitch-based carbon fiber; (2) Inelastic deformation of metal matrix laminates; (3) Analysis of fatigue damage in fibrous MMC laminates; (4) Delamination fracture toughness in thermoplastic matrix composites; (5) Numerical investigation of the microhardness of composite fracture; and (6) General beam theory for composite structures.

  17. Advanced composites X

    SciTech Connect

    1994-12-31

    In the past ten years, high volume, high performance applications of advanced composites in transportation have grown substantially. The 10th annual ASM/ESD Advanced Composites Conference and Exposition presents the latest developments in composite applications and technologies with over 70 papers presented. The conference is organized in tracks covering body, chassis, powertrain and infrastructure applications, material sciences, manufacturing processes and recycling. Polymer composite and metal matrix composite technologies are included throughout. Body sessions feature adhesive bonding, analysis and test methods and crash energy absorption. The Chassis sessions showcase polymer and metal composite applications. The Powertrain/Propulsion track includes emerging materials as well as design and processing case studies. The Materials Science track features papers on new materials, their performance and theoretical treatment. Manufacturing Processes sessions cover process, modelling, fiber preforming and emerging manufacturing methods. The Infrastructure and Recycling track includes a panel discussion of infrastructure applications and technical papers on the recycling of polymer composites and nondestructive testing.

  18. Suite versus composite statistics

    USGS Publications Warehouse

    Balsillie, J.H.; Tanner, W.F.

    1999-01-01

    Suite and composite methodologies, two statistically valid approaches for producing statistical descriptive measures, are investigated for sample groups representing a probability distribution where, in addition, each sample is probability distribution. Suite and composite means (first moment measures) are always equivalent. Composite standard deviations (second moment measures) are always larger than suite standard deviations. Suite and composite values for higher moment measures have more complex relationships. Very seldom, however, are they equivalent, and they normally yield statistically significant but different results. Multiple samples are preferable to single samples (including composites) because they permit the investigator to examine sample-to-sample variability. These and other relationships for suite and composite probability distribution analyses are investigated and reported using granulometric data.

  19. Hydrogen storage compositions

    DOEpatents

    Li, Wen; Vajo, John J.; Cumberland, Robert W.; Liu, Ping

    2011-04-19

    Compositions for hydrogen storage and methods of making such compositions employ an alloy that exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The composition includes a ternary alloy including magnesium, boron and a metal and a metal hydride. The ternary alloy and the metal hydride are present in an amount sufficient to render the composition capable of hydrogen storage. The molar ratio of the metal to magnesium and boron in the alloy is such that the alloy exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The hydrogen storage composition is prepared by combining magnesium, boron and a metal to prepare a ternary alloy and combining the ternary alloy with a metal hydride to form the hydrogen storage composition.

  20. Investigation of Composite Structures

    NASA Technical Reports Server (NTRS)

    Hyer, Michael W.

    2000-01-01

    This final report consists of a compilation of four separate written documents, three dealing with the response and failure of elliptical composite cylinders to an internal pressure load, and the fourth dealing with the influence of manufacturing imperfections in curved composite panels. The three focused on elliptical cylinders consist of the following: 1 - A paper entitled "Progressive Failure Analysis of Internally Pressurized Elliptical Composite Cylinders," 2 - A paper entitled "Influence of Geometric Nonlinearities on the Response and Failure of Internally Pressurized Elliptical Composite Cylinders," and 3 - A report entitled "Response and Failure of Internally Pressurized Elliptical Composite Cyclinders." The document which deals with the influence of manufacturing imperfections is a paper entitled "Manufacturing Distortions of Curved Composite Panels."

  1. Composite Intersection Reinforcement

    NASA Technical Reports Server (NTRS)

    Misciagna, David T. (Inventor); Fuhrer, Jessica J. (Inventor); Funk, Robert S. (Inventor); Tolotta, William S. (Inventor)

    2013-01-01

    An assembly and method for manufacturing a composite reinforcement for unitizing a structure are provided. According to one embodiment, the assembly includes a base having a plurality of pins extending outwardly therefrom to define a structure about which a composite fiber is wound to define a composite reinforcement preform. The assembly also includes a plurality of mandrels positioned adjacent to the base and at least a portion of the composite reinforcement preform, and a cap that is positioned over at least a portion of the plurality of mandrels. The cap is configured to engage each of the mandrels to support the mandrels and the composite reinforcement preform during a curing process to form the composite reinforcement.

  2. Composite intersection reinforcement

    NASA Technical Reports Server (NTRS)

    Misciagna, David T. (Inventor); Fuhrer, Jessica J. (Inventor); Funk, Robert S. (Inventor); Tolotta, William S. (Inventor)

    2010-01-01

    An assembly and method for manufacturing a composite reinforcement for unitizing a structure are provided. According to one embodiment, the assembly includes a base having a plurality of pins extending outwardly therefrom to define a structure about which a composite fiber is wound to define a composite reinforcement preform. The assembly also includes a plurality of mandrels positioned adjacent to the base and at least a portion of the composite reinforcement preform, and a cap that is positioned over at least a portion of the plurality of mandrels. The cap is configured to engage each of the mandrels to support the mandrels and the composite reinforcement preform during a curing process to form the composite reinforcement.

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The composite aircraft program component (CAPCOMP) is a graduate level project conducted in parallel with a composite structures program. The composite aircraft program glider (CAPGLIDE) is an undergraduate demonstration project which has as its objectives the design, fabrication, and testing of a foot launched ultralight glider using composite structures. The objective of the computer aided design (COMPAD) portion of the composites project is to provide computer tools for the analysis and design of composite structures. The major thrust of COMPAD is in the finite element area with effort directed at implementing finite element analysis capabilities and developing interactive graphics preprocessing and postprocessing capabilities. The criteria for selecting research projects to be conducted under the innovative and supporting research (INSURE) program are described.

  4. Indirect resin composites

    PubMed Central

    Nandini, Suresh

    2010-01-01

    Aesthetic dentistry continues to evolve through innovations in bonding agents, restorative materials, and conservative preparation techniques. The use of direct composite restoration in posterior teeth is limited to relatively small cavities due to polymerization stresses. Indirect composites offer an esthetic alternative to ceramics for posterior teeth. This review article focuses on the material aspect of the newer generation of composites. This review was based on a PubMed database search which we limited to peer-reviewed articles in English that were published between 1990 and 2010 in dental journals. The key words used were ‘indirect resin composites,’ composite inlays,’ and ‘fiber-reinforced composites.’ PMID:21217945

  5. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1988-01-01

    A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented.

  6. Galactic cosmic ray composition

    NASA Technical Reports Server (NTRS)

    Meyer, J. P.

    1986-01-01

    An assessment is given of the galactic cosmic ray source (GCRS) elemental composition and its correlation with first ionization potential. The isotopic composition of heavy nuclei; spallation cross sections; energy spectra of primary nuclei; electrons; positrons; local galactic reference abundances; comparison of solar energetic particles and solar coronal compositions; the hydrogen; lead; nitrogen; helium; and germanium deficiency problems; and the excess of elements are among the topics covered.

  7. Continuous Fiber Ceramic Composites

    SciTech Connect

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  8. Composite Material Switches

    NASA Technical Reports Server (NTRS)

    Javadi, Hamid (Inventor)

    2001-01-01

    A device to protect electronic circuitry from high voltage transients is constructed from a relatively thin piece of conductive composite sandwiched between two conductors so that conduction is through the thickness of the composite piece. The device is based on the discovery that conduction through conductive composite materials in this configuration switches to a high resistance mode when exposed to voltages above a threshold voltage.

  9. Collection and analysis of samples for polycyclic aromatic hydrocarbons in dust and other solids related to sealed and unsealed pavement from 10 cities across the United States, 2005-07

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, Barbara J.; Wilson, Jennifer T.; Burbank, Teresa L.

    2008-01-01

    Parking lots and driveways are dominant features of the modern urban landscape, and in the United States, sealcoat is widely used on these surfaces. One of the most widely used types of sealcoat contains refined coal tar; coal-tar-based sealcoat products have a mean polycyclic aromatic hydrocarbon (PAH) concentration of about 5 percent. A previous study reported that parking lots in Austin, Texas, treated with coal-tar sealcoat were a major source of PAH compounds in streams. This report presents methods for and data from the analysis of concentrations of PAH compounds in dust from sealed and unsealed pavement from nine U.S. cities, and concentrations of PAH compounds in other related solid materials (sealcoat surface scrapings, nearby street dust, and nearby soil) from three of those same cities and a 10th city. Dust samples were collected by sweeping dust from areas of several square meters with a soft nylon brush into a dustpan. Some samples were from individual lots or driveways, and some samples consisted of approximately equal amounts of material from three lots. Samples were sieved to remove coarse sand and gravel and analyzed by gas chromatography/mass spectrometry. Concentrations of PAHs vary greatly among samples with total PAH (sigmaPAH), the sum of 12 unsubstituted parent PAHs, ranging from nondetection for all 12 PAHs (several samples from Portland, Oregon, and Seattle, Washington; sigmaPAH of less than 36,000 micrograms per kilogram) to 19,000,000 micrograms per kilogram for a sealcoat scraping sample (Milwaukee, Wisconsin). The largest PAH concentrations in dust are from a driveway sample from suburban Chicago, Illinois (sigmaPAH of 9,600,000 micrograms per kilogram).

  10. Collection and Analysis of Samples for Polycyclic Aromatic Hydrocarbons in Dust and Other Solids Related to Sealed and Unsealed Pavement From 10 Cities Across the United States, 2005-07

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, Barbara J.; Wilson, Jennifer T.; Burbank, Teresa L.

    2008-01-01

    Parking lots and driveways are dominant features of the modern urban landscape, and in the United States, sealcoat is widely used on these surfaces. One of the most widely used types of sealcoat contains refined coal tar; coal-tar-based sealcoat products have a mean polycyclic aromatic hydrocarbon (PAH) concentration of about 5 percent. A previous study reported that parking lots in Austin, Texas, treated with coal-tar sealcoat were a major source of PAH compounds in streams. This report presents methods for and data from the analysis of concentrations of PAH compounds in dust from sealed and unsealed pavement from nine U.S. cities, and concentrations of PAH compounds in other related solid materials (sealcoat surface scrapings, nearby street dust, and nearby soil) from three of those same cities and a 10th city. Dust samples were collected by sweeping dust from areas of several square meters with a soft nylon brush into a dustpan. Some samples were from individual lots or driveways, and some samples consisted of approximately equal amounts of material from three lots. Samples were sieved to remove coarse sand and gravel and analyzed by gas chromatography/mass spectrometry. Concentrations of PAHs vary greatly among samples with total PAH (sigmaPAH), the sum of 12 unsubstituted parent PAHs, ranging from nondetection for all 12 PAHs (several samples from Portland, Oregon, and Seattle, Washington; sigmaPAH of less than 36,000 micrograms per kilogram) to 19,000,000 micrograms per kilogram for a sealcoat scraping sample (Milwaukee, Wisconsin). The largest PAH concentrations in dust are from a driveway sample from suburban Chicago, Illinois (sigmaPAH of 9,600,000 micrograms per kilogram).

  11. Cometary dust composition

    NASA Technical Reports Server (NTRS)

    Gehrz, R. D.; Hanner, M. S.

    1988-01-01

    The earth based measurements and in situ sampling of Comet Halley have provided new data about the chemical composition of cometary grains. Recent progress in laboratory studies of interplanetary dust particles (IDPs) complement the comet data, allowing inferences about the mineralogy and physical structure of the comet dust to be drawn from the observed elemental composition and infrared spectra. The in situ dust composition measurements at Halley, the composition of IDPs and their relation to comet dust, and the origin of the 3.4 micron hydrocarbon feature is discussed. Related discussion is also presented on aromatic components in comets and the 3.4 micron feature. These topics are briefly summarized.

  12. Composition for detecting uranyl

    SciTech Connect

    Baylor, L.C.; Stephens, S.M.

    1995-06-13

    A composition for detecting the presence and concentration of a substance, such as uranyl, comprises an organohalide covalently bonded to an indicator for said substance. The composition has at least one active OH site for forming a complex with the substance to be detected. The composition is made by reacting equimolar amounts of the indicator and the organohalide in a polar organic solvent. The absorbance spectrum of the composition-uranyl complex is shifted with respect to the absorbance spectrum of the indicator-uranyl complex, to provide better spectral resolution for detecting uranyl. 6 figs.

  13. Polyimide composites: Application histories

    NASA Technical Reports Server (NTRS)

    Poveromo, L. M.

    1985-01-01

    Advanced composite hardware exposed to thermal environments above 127 C (260 F) must be fabricated from materials having resin matrices whose thermal/moisture resistance is superior to that of conventional epoxy-matrix systems. A family of polyimide resins has evolved in the last 10 years that exhibits the thermal-oxidative stability required for high-temperature technology applications. The weight and structural benefits for organic-matrix composites can now be extended by designers and materials engineers to include structures exposed to 316 F (600 F). Polyimide composite materials are now commercially available that can replace metallic or epoxy composite structures in a wide range of aerospace applications.

  14. Pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  15. Probabilistic composite analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Murthy, P. L. N.

    1991-01-01

    Formal procedures are described which are used to computationally simulate the probabilistic behavior of composite structures. The computational simulation starts with the uncertainties associated with all aspects of a composite structure (constituents, fabrication, assembling, etc.) and encompasses all aspects of composite behavior (micromechanics, macromechanics, combined stress failure, laminate theory, structural response, and tailoring) optimization. Typical cases are included to illustrate the formal procedure for computational simulation. The collective results of the sample cases demonstrate that uncertainties in composite behavior and structural response can be probabilistically quantified.

  16. Electrically conductive cellulose composite

    DOEpatents

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  17. RADIATION SHIELDING COMPOSITION

    DOEpatents

    Dunegan, H.L.

    1963-01-29

    A light weight radiation shielding composition is described whose mechanical and radiological properties can be varied within wide limits. The composition of this shielding material consists of four basic ingredients: powder of either Pb or W, a plastic resin, a resin plasticizer, and a polymerization catalyst to promote an interaction of the plasticizer with the plastic resin. Air may be mixed into the above ingredients in order to control the density of the final composition. For equivalent gamma attenuation, the shielding composition weighs one-third to one-half as much as conventional Pb shielding. (AEC)

  18. Composition for detecting uranyl

    DOEpatents

    Baylor, Lewis C.; Stephens, Susan M.

    1995-01-01

    A composition for detecting the presence and concentration of a substance such as uranyl, comprising an organohalide covalently bonded to an indicator for said substance. The composition has at least one active OH site for forming a complex with the substance to be detected. The composition is made by reacting equimolar amounts of the indicator and the organohalide in a polar organic solvent. The absorbance spectrum of the composition-uranyl complex is shifted with respect to the absorbance spectrum of the indicator-uranyl complex, to provide better spectral resolution for detecting uranyl.

  19. Reactive composite compositions and mat barriers

    DOEpatents

    Langton, Christine A.; Narasimhan, Rajendran; Karraker, David G.

    2001-01-01

    A hazardous material storage area has a reactive multi-layer composite mat which lines an opening into which a reactive backfill and hazardous material are placed. A water-inhibiting cap may cover the hazardous material storage area. The reactive multi-layer composite mat has a backing onto which is placed an active layer which will neutralize or stabilize hazardous waste and a fronting layer so that the active layer is between the fronting and backing layers. The reactive backfill has a reactive agent which can stabilize or neutralize hazardous material and inhibit the movement of the hazardous material through the hazardous material storage area.

  20. Composite materials: Testing and design

    NASA Technical Reports Server (NTRS)

    Whitcomb, John D. (Editor)

    1988-01-01

    The present conference discusses topics in the analysis of composite structures, composite materials' impact and compression behavior, composite materials characterization methods, composite failure mechanisms, NDE methods for composites, and filament-wound and woven composite materials' fabrication. Attention is given to the automated design of a composite plate for damage tolerance, the effects of adhesive layers on composite laminate impact damage, instability-related delamination growth in thermoset and thermoplastic composites, a simple shear fatigue test for unidirectional E-glass epoxy, the growth of elliptic delaminations in laminates under cyclic transverse shear, and the mechanical behavior of braided composite materials.