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1

Recycling of pavement materials  

E-print Network

was recycled. Mixing was accom- plished by using a 10-by $0-foot drum mixer with a low efficiency wet wash. This mixer had an asphalt line in- side the drum and introduced $. 5 percent asphalt by weight into the old pavement which contained. ). 7 percent... material from old asphalt pavement and coarse aggregate. One and one- half percent emulsion was added. Air pollution seemed to be the biggest problem. Warren Brothers feel that the main objective of recycling is to utilize existing plants with minor...

O'Neal, Randy Jim

1976-01-01

2

Improving Rutting Resistance of Pavement Structures Using Geosynthetics: An Overview  

PubMed Central

A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

2014-01-01

3

Improving rutting resistance of pavement structures using geosynthetics: an overview.  

PubMed

A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

Mirzapour Mounes, Sina; Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

2014-01-01

4

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...

5

Integrated Materials and Construction Practices (IMCP) for Concrete Pavement  

E-print Network

Integrated Materials and Construction Practices (IMCP) for Concrete Pavement Workshop Participant Handbook Prepared for Prepared by Federal Highway Administration National Concrete Pavement Technology and Construction Practices for Concrete Pavements Workshop Participant Handbook--Front Matter i Technical Report

6

Filtration and clogging of permeable pavement loaded by urban drainage.  

PubMed

Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (?(e)) of 24% and median pore size of 658 ?m with a standard deviation of 457 ?m. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 ?m and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 × 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage. PMID:22123518

Sansalone, J; Kuang, X; Ying, G; Ranieri, V

2012-12-15

7

Contemporary biogenic formation of clay pavements by eucalypts: further support for the phytotarium concept  

PubMed Central

Background and Aims Clayey (sodosolic) pavements were studied in lateral root catchments of eucalypts where mixed myrtaceous:proteaceous vegetation was colonizing a dune of quartzitic sand blown out from a playa lake during late Pleistocene times. The site at Chillinup in south-west Western Australia provided an opportunity to examine these signature pavements in an unequivocally recent setting, and to assess their effects on competing non-eucalypt vegetation. Methods Pavements were located, and their extents and depths assessed by probing with steel rods, followed by corings and pit excavations using an air spade. Listings of plant species, growth forms and root morphologies were assembled for different vegetation zones in a representative transect across the dune. A deep cutting through the dune provided details on pavement morphology and modifications to the sand deposit bioengineered by eucalypt and heath vegetation. Key Results Clay pavements comprised closely spaced, round-topped columns whose mean diameters and depths varied between eucalypt species. Incipient pavement formation was characterized by clumps of clay deposited around fine root material. Pavements appeared to have been synthesized in situ from locally accessed and imported constituents. Understoreys on superficial pavements of a tree eucalypt were considerably less dense and biodiverse than on the deeper pavements of two mallee species, whilst most profuse vegetation cover was encountered in heath on unmodified (non-pavemented) sand. Certain species were restricted to superficially located pavements, whilst other ‘generalist’ species occurred widely across the dune. Relict pavements formed by earlier generations of eucalypts were present in certain areas of the transect and in soil profiles of the cutting. Some relict pavements colonized by proteaceous shrubs were overprinted with ferricrete. Conclusions Clay pavements formed by eucalypts have pronounced effects on understorey vegetation and may have been instrumental in establishment of the complex mosaics of mallee-woodland and proteaceous heathland observed across semi-arid landscapes of south-west Western Australia. Findings are related to earlier observations on the range of plant-mediated changes in soil profiles discussed in the recently advanced ‘Phytotarium’ concept. PMID:19141601

Pate, John S.; Verboom, William H.

2009-01-01

8

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...

9

Development of Improved Pavement Performance Prediction Models for the Indiana Pavement Management System  

Microsoft Academic Search

The Indiana Department of Transportation (INDOT) is increasingly committed to the Pavement Management System. For this reason, updated simple pavement performance prediction models with the least number of explanatory (independent) variables are required to predict the performance of various pavement types for future planning of rehabilitation or replacement. In Indiana, the two main pavement types are jointed concrete pavement (JCP)

Sedat Gulen; Karen Zhu; John Weaver; Jie Shan; William F. Flora

2001-01-01

10

General outlook of pavement and vehicle dynamics  

SciTech Connect

The interaction between vehicle and pavement is complex since pavement roughness excites the dynamic forces generated by vehicles, while these dynamic forces simultaneously increase the pavement roughness. The objective of this paper is to provide an overview of the results of recent research related to pavement and vehicle dynamics and their interaction and to evaluate their potential use in the design and management of pavements. Pavement dynamic models are capable of determining stresses, strains, and deflections in various directions when harmonic, pulse, or transient loads are applied. Vehicle dynamic models simulate the effect of pavement roughness on the inertia of various vehicle components. These models can predict the dynamic forces produced by different axles and wheels of traveling vehicles at different locations along the pavement. Pavement response computed using dynamic models matches field measurements closer than those computed using static models. The concept of vehicle-pavement interaction can be applied to weigh-in-motion, pavement design and performance, and vehicle regulations.

Mamlouk, M.S. [Arizona State Univ., Tempe, AZ (United States). Dept. of Civil and Environmental Engineering

1997-11-01

11

Review of the development of concrete pavement surface types and their acoustic performance with time  

NASA Astrophysics Data System (ADS)

Roadways have been constructed out of concrete pavements in the United States since the late 1800s. Numerous surface textures have been produced including burlap drag, astroturf, uniformly and random transverse tined, longitudinally tined, and both profile and whisper diamond grinding processes. Each surface evolved for specific reasons during the historical development of Portland Cement Concrete Pavements (PCCP).This paper reviews the development of these various surface texture types and the reasons for their evolution. In addition, results from both far field and near field acoustic testing are presented to evaluate the ``acoustic'' performance of these surfaces over time.For five surface types, 1/24 octave analysis were conducted on CPX data obtained with a single tire. The spectrum of each of these surface types is presented for comparison. For three of the surfaces, speed gradient testing, ranging between 25-75 MPH was conducted. 1/24 octave analysis of each of these runs was conducted so that that any speed induced spectrum shifts could be observed.The results to date indicate that the adverse tonal properties of some PCCP surfaces can be eliminated through diamond grinding and prevented by not constructing transverse tined PCCP.

Scofield, Larry A.

2005-09-01

12

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

PubMed

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

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

2012-01-01

13

GPR-based evaluation of strength properties of unbound pavement material from electrical characteristics  

NASA Astrophysics Data System (ADS)

It is well known that inter-particle friction and cohesion of soil particles and aggregates deeply affect the strength and deformation properties of soils, exerting critical effects on the bearing capacity of unbound pavement materials. In that respect, considering that strength characteristics of soil are highly dependent on particle interactions, and assuming a relationship between electric properties (e.g. electric permittivity) and bulk density of materials, a good correlation between mechanical and electric characteristics of soil is expected. In this work, Ground Penetrating Radar (GPR) techniques are used to investigate this topic. Two GPR equipment with same electronic characteristics and different survey configurations are used. Each radar operates with two ground-coupled antennae at 600 MHz and 1600 MHz central frequencies. Measurements are developed using 4 channels, 2 mono-static and 2 bi-static. The received signal is sampled in the time domain at dt = 7.8125 × 10-2 ns, and in the space domain every 2.4 × 10-2 m. A semi-empirical model is proposed for predicting the resilient modulus of sub-asphalt layers from GPR-derived data. Basically, the method requires to follow two steps. Firstly, laboratory tests are carried out for calibration, with the main focus to provide consistent empirical relationships between physical (e.g. bulk density) and electric properties. The second step is focused on the in-situ validation of results through soil strength measurements retrieved by CBR tests and Light Falling Weight Deflectometer (LFWD). On the basis of traditional empirical equations used for flexible pavement design, the following expression is proposed: -m Ei = ?j?hj,i j=1 where Ei [MPa] is the ith expected resilient modulus of the surveyed soil under the line of scan, hj,i [m] is the ith thickness referred to the jth layer, and ?j is a dielectric parameter calibrated as a function of the relative electric permittivity. The experimental setting requires the use of road material, typically employed for subgrade and subbase courses. Different types of soil ranging from group A1 to A4 by AASHTO soil classification system, are analyzed. As regards the laboratory experiments, material is gradually compacted in electrically and hydraulically isolated test boxes. A large metal sheet supports the experimental boxes, so that the transmitted GPR signal is totally reflected. GPR inspections are carried out for any compaction step up to the maximum density value available. Moreover, in-situ tests are carried out on targeted types of soil, with grain size distribution and texture comparable to those analyzed in laboratory environment. The results of this study confirm a promising correlation between the electric permittivities and the strength and deformation properties of the surveyed soils. Laboratory analyses show that the relationship between the relative permittivity and the bulk density is positive: the higher the density of the compacted soil sample, the higher the electric permittivity of the medium. Analogously, in-situ validation presents a good comparison between measured and predicted data. Percentage errors less than 20% demonstrate that a reliable prediction of Young Modulus using this GPR-based approach can be achieved.

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

2013-04-01

14

Impact of the variation in dynamic vehicle load on flexible pavement responses  

NASA Astrophysics Data System (ADS)

The purpose of this research was to evaluate the dynamic variation in asphalt pavement critical responses due to dynamic tire load variations. An attempt was also made to develop generalized regression equations to predict the dynamic response variation in flexible pavement under various dynamic load conditions. The study used an extensive database of computed pavement response histories for five different types of sites (smooth, rough, medium rough, very rough and severely rough), two different asphalt pavement structures (thin and thick) at two temperatures (70 °F and 104 °F), subjected to a tandem axle dual tire at three speeds 25, 37 and 50 mph (40, 60 and 80 km/h). All pavement responses were determined using the 3D-Move Analysis program (Version 1.2) developed by University of Nevada, Reno. A new term called Dynamic Response Coefficient (DRC) was introduced in this study to address the variation in critical pavement responses due to dynamic loads as traditionally measured by the Dynamic Load Coefficient (DLC). While DLC represents the additional varying component of the tire load, DRC represents the additional varying component of the response value (standard deviation divided by mean response). In this study, DRC was compared with DLC for five different sites based on the roughness condition of the sites. Previous studies showed that DLC varies with vehicle speed and suspension types, and assumes a constant value for the whole pavement structure (lateral and vertical directions). On the other hand, in this study, DRC was found to be significantly varied with the asphalt pavement and function of pavement structure, road roughness conditions, temperatures, vehicle speeds, suspension types, and locations of the point of interest in the pavement. A major contribution of the study is that the variation of pavement responses due to dynamic load in a flexible pavement system can be predicted with generalized regression equations. Fitting parameters (R2) in the rage of 0.60 to 0.87 were observed the DRC predictive equations. In addition, verification of those generalized equations was evaluated using different sets of asphalt pavement structures and pavement materials. The differences between calculated and predicted values were found to be within +/-20% for the maximum tensile strain and +/-30% for the maximum compressive strain in the asphalt layer.

Ahsanuzzaman, Md

15

STATUS OF POROUS PAVEMENT RESEARCH  

EPA Science Inventory

This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available stormwater management techniq...

16

Project Information Form Project Title White Paper on The application of permeable pavement with emphasis  

E-print Network

Project Information Form Project Title White Paper on The application of permeable pavement (by each agency or organization) Cal Trans Total Project Cost $29,007 Agency ID or Contract Number Project Depending on the type of surface pavement, permeable pavement can be termed as porous asphalt

California at Davis, University of

17

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

PubMed

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

Liu, Xiaoyu; Cui, Qingbin; Schwartz, Charles

2014-01-01

18

Bridge and pavement maintenance  

NASA Astrophysics Data System (ADS)

Deterioration of New York State Highway structures; precast repair of continuously reinforced concrete pavement (abridgment) patching of continuously reinforced concrete pavements, evaluation of several maintenance methods for continuously reinforced concrete pavement, patching jointed concrete pavements, highway pavement repairs by using polymer concrete, pressure grouting of concrete pavements, and choosing cost-effective maintenance are discussed.

Fitzpatrick, M. W.; Law, D. A.; Dixon, W. C.; Elkins, G. E.; Mucullough, B. F.; Darter, M. I.; Yoder, E. J.; Florence, R. H., Jr.; Virkler, S. J.; McGhee, K. H.

1981-03-01

19

Evaluation of the existing performance models used for pavement management by the Texas Department of Transportation  

E-print Network

Development of Performance Models Considerations Types of Models Data Analysis Empirical Models . Regression Models Survivor Curves Markov Models Semi-Markov Models nl v VI V11 X1 Xlv 4 5 7 7 8 10 11 11 13 13 14 15 16 18 19... 174 175 175 177 177 179 180 182 183 185 186 188 LIST OF FIGURES Figure Page 1 Typical Regression Curves 2 A Typical Survivor Curve . . 3 Difference between Markov and Semi-Markov Models . . 4 Definition of Thick Pavement by Classical...

Mukherjee, Biswajit

1998-01-01

20

Equations for predicting the layer stiffness moduli in pavement systems containing lime-flyash stabilized materials  

E-print Network

properties from Dynaflect data for the Texas flexible pave- ment system. For pavements of known thickness resting on homogenous subgrade of infinite depth and assuming a Poisson's ratio of 0. 5, Scrivner's approximated equation is of the general form: 4E...EOUATIONS FOR PREDICTING THE LAYER STIFFNESS ' MODULI IN PAVEMENT SYSTEMS CONTAINING LIME-FLYASH STABILIZED MATERIALS A Thesis by SHAH MANZOOR ALAM Submitted to the Graduate College of Texas AN University in partial fulfillment...

Alam, Shah Manzoor

1984-01-01

21

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

SciTech Connect

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, which we call the chipping and aggregate methods, and calculated their potential life cycle costs. By analyzing the potential for increased pavement durability resulting from these conceptual approaches, we then estimated the incremental costs that would allow them to be cost-effective compared to conventional AC. For our example case of Los Angeles, we found that those allowable incremental costs range from less than dollar 1 to more than dollar 11 per square yard (dollar 1 to dollar 13 per square meter) depending on street type and the condition of the original pavement. Finally, we evaluated the main actors in the pavement market and the existing and potential market barriers associated with reflective pavements. Apart from situations where lifecycle costs are high compared to conventional AC, all reflective paving technologies face a cultural barrier based on the belief that black is better. For PCC, high first costs were found to be the most significant economic barrier, particularly where agencies are cons trained by first cost. Lack of developer standards was found to be a significant institutional barrier to PCC since developers are often not held accountable for the long-term maintenance of roads after initial construction, which creates a misplaced incentive to build low first-cost pavements. PCC also faces site-specific barriers such as poorly compacted base soils and proximity to areas of frequent utility cutting.

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

2001-11-21

22

Contribution of lateral processes to stone pavement formation in deserts inferred from clast orientation patterns  

NASA Astrophysics Data System (ADS)

Stone pavements are widespread landforms of arid environments. They typically develop by accretionary rise above a thickening aeolian mantle which usually contains a surficial vesicular unit. Hence, stone pavements are regarded as stable landforms and, thus, are often used as surface-age indicators. We studied orientation patterns of pavement clasts and depict their geometrical properties. We introduce a new statistical approach for quantitative description of circular data. From four study regions in a wide variety of environmental settings we show that preferred, non-random orientation of clast length axes is a recurrent feature of modern stone pavements. Orientation is primarily determined by no other relief parameter than slope aspect. In 40 out of 52 measured plots an angle of 72 ± 9° separates two angle maxima. The same patterns are present in stone lines buried under a cover of aeolian dust. We interpret these features as fossil stone pavements, accordingly. Furthermore, on artificially cleared plots disturbed stone pavements begin to recover within few months by a process which creates essentially the same orientation pattern. We suggest that lateral surficial processes such as unconcentrated overland flow and creep contribute to the formation and maintenance of stone pavements as well as to this preferred clast orientation. They arrange clasts symmetrical to slope aspect with an angle determined by the axes ratio of the transported object. This results in the frequent bimodal pattern of stone length axes. This special type of transport requires previous accumulation of aeolian material forming a fine grained, even vesicular layer. Thus, there is close relationship between stone pavement and vesicular layer. We conclude that lateral processes take part in stone pavement formation. The commonly accepted model of dust accretion, which is not rendered obsolete by our findings, has to be complemented by this lateral component. This has implications for the stability of stone pavement-covered surfaces and for their applicability as age indicators. Quickly resealing disturbances as well as fossilised stone pavements imply this prominent desert surface feature may become fragile and transient.

Dietze, Michael; Kleber, Arno

2012-02-01

23

Vibration of vehicle-pavement coupled system based on a Timoshenko beam on a nonlinear foundation  

NASA Astrophysics Data System (ADS)

This paper focuses on the coupled nonlinear vibration of vehicle-pavement system. The pavement is modeled as a Timoshenko beam resting on a six-parameter foundation. The vehicle is simplified as a spring-mass-damper oscillator. For the first time, the dynamic response of vehicle-pavement coupled system is studied by modeling the pavement as a Timoshenko beam resting on a nonlinear foundation. Consequently, the shear effects and the rotational inertia of the pavement are included in the modeling process. The pavement model is assumed to be a linear-plus-cubic Pasternak-type foundation. Furthermore, the convergent Galerkin truncation is used to obtain approximate solutions to the coupled vibratory response of the vehicle-pavement coupled system. The dynamic responses of the vehicle-pavement system with the asphalt pavement on soft soil foundation are investigated via the numerical examples. The numerical results show that the calculation for the coupled vibratory response needs high-order modes. Moreover, the coupling effects between the pavement and the vehicle are numerically examined by using the convergent modal truncation. The physical parameters of the vehicle-pavement system such as the shear modulus are compared for determining their influences on the coupled vibratory response.

Ding, Hu; Yang, Yan; Chen, Li-Qun; Yang, Shao-Pu

2014-12-01

24

Permeable Pavement  

NSDL National Science Digital Library

Students investigate how different riparian ground covers, such as grass or pavement, affect river flooding. They learn about permeable and impermeable materials through the measurement how much water is absorbed by several different household materials in a model river. Students use what they learn to make recommendations for engineers developing permeable pavement. Also, they consider several different limitations for design in the context of a small community.

Integrated Teaching and Learning Program,

25

Generation mechanisms of tire-pavement noise  

NASA Astrophysics Data System (ADS)

Tire-pavement noise is the dominant source of traffic noise at highway speeds. It is the result of a combination of several noise generation mechanisms, including tire carcass vibration and tread block vibration. Because multiple mechanisms are involved, it is difficult to predict the effects of changes in pavement parameters on tire-pavement noise. In this research, a set of experimental techniques were developed to decompose a measured tire-pavement noise spectrum into a set of constituent spectra relating to each generation mechanism. Three principal mechanisms were identified: treadband vibration, sidewall vibration, and tangential tread block vibration. By combining the constituent spectra associated with these mechanisms, it was possible to accurately predict the total tire-pavement noise spectrum. The constituent spectra were fit to tire-pavement noise data measured on asphalt and concrete pavements at highway speeds. It was found that the constituent spectra fit the measured data well, and a two-parameter model was developed to predict tire-pavement noise levels from pavement texture data.

Dare, Tyler P.

26

Possible environmental impacts of recycled glass used as a pavement base material.  

PubMed

In theory, glass diverted or recovered from the municipal solid waste (MSW) stream can be used as feedstock (glass cullet) in the production of new glass containers. However, post-consumer glass typically contains a mixture of clear and coloured material and is often contaminated with other wastes; characteristics that are impediments to the production of new containers. Sorting and cleaning of glass diverted from MSW to make it feasible for use in bottle industries are also time consuming and costly tasks. There is, however, the potential to use recycled glass as a sub-base material for road pavement construction. Geotechnical investigations to date suggest that use of recycled glass as a roadway sub-base could be cost-effective, and thus preclude the need for expensive sorting. There is, however, the necessessity to further investigate the potential short- and long-term toxicity, health hazards, and/or environmental pollution associated with use of mixed glass cullet as an aggregate, considering conditions during stockpiled storage and after placement. The results of laboratory tests on recycled glass regarding its potential to release pollutants to the environment via leaching are presented herein. Five random samples of crushed glasses were collected from a recycling company in Melbourne, Australia. The parameters tested for each sample were total organic matter, heavy metals, sulfates, chlorides, conductivity, pH and surfactant levels. It wais found that in most cases, the contamination levels were within the State of Victoria's Environmental Protection Agency-specified limits for manual handling, thus indicating that recycled glass could probably be safely used in pavement sub-bases. PMID:22627644

Imteaz, Monzur Alam; Ali, M M Younus; Arulrajah, Arul

2012-09-01

27

Aquatic toxicity of airfield-pavement deicer materials and implications for airport runoff  

USGS Publications Warehouse

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.

Corsi, S.R.; Geis, S.W.; Bowman, G.; Failey, G.G.; Rutter, T.D.

2009-01-01

28

Investigation of Self Consolidating Concrete Containing High Volume of Supplementary Cementitious Materials and Recycled Asphalt Pavement Aggregates  

NASA Astrophysics Data System (ADS)

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 recommended to replace the coarse aggregate in SCC by more than 25% RAP.

Patibandla, Varun chowdary

29

MODELING PAVEMENT DETERIORATION PROCESSES BY POISSON HIDDEN MARKOV MODELS  

NASA Astrophysics Data System (ADS)

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.

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

30

An evaluation of pavement markings and raised pavement markers at left exit lane drops  

E-print Network

AN EVALUATION OF PAVEMENT MARKINGS AND RAISED PAVEMENT MARKERS AT LEFT EXIT LANE DROPS A Thesis by MARTY TINA LANCE Submitted to Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved... Markings and Raised Pavement Markers at Left Exit Lane Drops. (August 1994) Marty Tina Lance, B. S. , Lander University; B. S. , Clemson University Chair of Advisory Cominittee: Dr. Thomas Urbanik II Most highway engineers agree that freeway exit lane...

Lance, Marty Tina

1994-01-01

31

Laboratory evaluation of selected syncrude products and upgraded by-products as pavement-recycling agents  

SciTech Connect

The following conclusions appear warranted based on the information derived from this study: (1) Selected syncrude products and upgraded by-products may be successfully used as recycling agents for field aged asphalt pavements. Those tested in this study performed equally as well as the commercially produced recycling agents. (2) Several of the blends containing the syncrude recycling agents exhibited excessive hardening and weight loss upon exposure to the thin film oven test. (3) Properties of recycled mixtures are highly dependent upon the type and amount of recycling agent. (4) The Rostler-Sternberg separation analysis on both the syncrudes and syncrude blends does not seem to produce results that correlate with other recycling agents. (5) Rostler-Sternberg analysis indicated a relatively high fraction of nitrogen bases in the syncrude additives, particularly those from shale oil. Although basic nitrogen in asphalts has been associated with improved resistance to moisture, recycled mixtures containing these materials did not exhibit any significant improvement in resistance to damage by water. Recycled mixtures containing recycling agent 4 (a soft tar sand asphalt) imparted excellent flexibility and yet adequate strength to paving mixtures at low service temperatures. (7) All of the blends containing the syncrude-based recycling agents, except California Coastal with recycling agent 3 (Tar Sand Asphalt and Stabilized Shale Oil), met criteria set forth by Halstead and Krchma for acceptable field performance. (8) The syncrude-based recycling agents produced blends with Rostler parameters and N/P values nearer those of the original asphalts than the commercial recycling agents. (9) According to Rostler-Sternberg analyses, none of the recycling agents were able to restore a base asphalt to its original composition, but this was not and should be not expected. 33 figures, 21 tables.

Holmgreen, R.J. Jr.; Epps, J.A.; Button, J.W.; Cook, O.C.

1982-01-01

32

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

PubMed Central

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

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

2014-01-01

33

Effects of using silica fume and polycarboxylate-type superplasticizer on physical properties of cementitious grout mixtures for semiflexible pavement surfacing.  

PubMed

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

Koting, Suhana; Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S; Ibrahim, Mohd Rasdan; Katman, Herdayati; Husain, Nadiah Md

2014-01-01

34

Making "Magic" Sidewalks of Pervious Pavement  

NSDL National Science Digital Library

Students use everyday building materials—sand, pea gravel, cement and water—to create and test pervious pavement. They learn what materials make up a traditional, impervious concrete mix and how pervious pavement mixes differ. Groups are challenged to create their own pervious pavement mixes, experimenting with material ratios to evaluate how infiltration rates change with different mix combinations.

2014-09-18

35

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses AGENCY...specific pavement types used in Federal-aid highway traffic noise analyses. Current...include additional pavement types in Federal-aid highway traffic noise analyses....

2013-05-08

36

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

PubMed

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

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

2014-06-15

37

Evaluation of Multilayered Pavement Structures from Measurements of Surface Waves  

NASA Astrophysics Data System (ADS)

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.

Ryden, Nils; Lowe, Michael J. S.; Cawley, Peter; Park, Choon B.

2006-03-01

38

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

39

Simulation of cooling effect of newly-innovated urban pavements on water and heat budgets  

NASA Astrophysics Data System (ADS)

People often suffer from the intense summer heat in Japan. This trend is increasing in urban areas because of the heat island effect and global warming. The present research evaluated the effect of pavements made of traditional and new materials on water and heat budgets. We coupled the NIES Integrated Catchment-based Eco- hydrology (NICE) model (Nakayama, 2007; Nakayama and Watanabe, 2004, 2006, 2007; Nakayama et al., 2006, 2007) to an urban canopy model in order to simulate the water and heat budgets in various types of natural and artificial pavements (covered by lawn, concrete, steel plate, synthetic rubber sheet, infiltration and water-holding blocks), and to evaluate the role of a new surface material in promoting evaporation and cooling to counter the heat island phenomenon (NICE-URBAN), by comparing with the simplified empirical model. Furthermore, using the heat conductivities of natural soil, we arranged these values for artificial pavement in the model equations by including the effect of the amount of water on the heat characteristics in the material. The simulated belowground water agreed with the observed value because this model includes the processes of both interception store and soil moisture store. The NICE-URBAN simulated more correctly the cooling of water-holding pavement during the intense heat of summer in an urban area than the empirical model. Because the model estimates that the air temperature at the water-holding pavement is 2 (deg.) lower than that at the lawn and 5 (deg.) lower than that at the building rooftop, it is very powerful to use this material for positive cooling effect in combination with the lawn for passive cooling effect. The simulation of NICE-URBAN showed that the decrease of surface temperature in water-holding pavement is closely related to the promotion of evaporation from the surface, the water volume of the pavement and the surface reflectance. References; 1)Nakayama,T.,Watanabe,M.,WRR,40,doi:10.1029/2004WR003174,2004. 2)Nakayama,T.,Watanabe,M.,HESSD,3,2101-2144,2006. 3)Nakayama,T.,et al.,HP,20(16),3441-3466,doi:10.1002/hyp.6142,2006. 4)Nakayama,T.,Ecol.Model.,2007(revised). 5)Nakayama,T.,Watanabe,M.,HP,doi:10.1002/hyp.6684,2007. 6)Nakayama,T.,et al.,STOTEN,373(1),270-288,doi:10.1016/j.scitotenv.2006.11.033,2007.

Nakayam, T.; Fujita, T.

2007-12-01

40

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

PubMed

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

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

2013-03-30

41

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

PubMed Central

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 11.2?m 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.

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

2008-01-01

42

TYPE-ONE PROTEIN PHOSPHATASE4 Regulates Pavement Cell Interdigitation by Modulating PIN-FORMED1 Polarity and Trafficking in Arabidopsis.  

PubMed

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

Guo, Xiaola; Qin, Qianqian; Yan, Jia; Niu, Yali; Huang, Bingyao; Guan, Liping; Li, Yuan; Ren, Dongtao; Li, Jia; Hou, Suiwen

2015-03-01

43

Nondestructive Evaluation of Pavements Ultrasonic  

E-print Network

Nondestructive Evaluation of Pavements Ð Ultrasonic Tomography Kyle Hoegh, Graduate Student Dr. Lev ­! The transducers act on the test object surface with oscillating piezoelectric elements for wave production from the specs (about 3 miles of testing in 50 ft intervals). Field Application ­ Atlanta Georgia

Minnesota, University of

44

Modelling of pavement materials on steel decks using the five-point bending test: Thermo mechanical evolution and fatigue damage  

Microsoft Academic Search

This paper deals with the modelling of wearing courses on steel orthotropic decks such as the Millau viaduct in France. This is of great importance when dealing with durability: due to the softness of such a support, the pavement is subjected to considerable strains that may generate top-down cracks in the layer at right angles of the orthotropic plate stiffeners

L. Arnaud; A. Houel

2010-01-01

45

LRRB Pavement Management Systems Pavement Management Systems  

E-print Network

LRRB Pavement Management Systems Pavement Management Systems Presented by: Michael Marti SRF devoted to local road research § Research is: · Managed by the LRRB · Conducted by DOT, U of M, Mn for implementing and monitoring research results (RIC) #12;LRRB Pavement Management Systems LRRB Structure LRRB

Minnesota, University of

46

The use of fluvial and marine sediments in the formulation of roller compacted concrete for use in pavements.  

PubMed

In the manufacture of Roller Compacted Concrete (RCC) used for pavement materials, various types of aggregates are used, such as crushed and rolled limestone or siliceous aggregates. The main objective is always to reach the maximum compactness to achieve higher mechanical performances. In the present work, fluvial and marine sediments, resulting from the dredging of harbours and rivers, were introduced as aggregates in the preparation of RCC for pavement construction, with a view to improving the mechanical strength of the RCC. This study included a granulometric, mineralogical and chemical characterization of the aggregates. The work also contains a mechanical characterization of the resulting material. The objective of the study was to find a resistant RCC, by developing materials such as sediments that are often classified as a waste and where their storage is harmful to the environment. The mechanical strengths obtained showed the profitability of using a Roller Compacted Concrete containing sediments. PMID:19705664

Zdiri, M; Abriakb, N E; Ben Ouezdoua, M; Neji, J

2009-07-01

47

Types of Materials  

NSDL National Science Digital Library

This webpage from Edmonds Community College provides a brief introduction to a number of core materials including ceramics, composites, concrete, electronic/optical, metals, polymers/plastics and wood.

48

Evaluation of pavement base and subgrade material properties and test procedures  

E-print Network

Parameters . Soil Suction 4 4 14 16 III LABORATORY INVESTIGATION AND RESULTS. . . . 21 Introduction Specific Gravity Particle Size Analysis Moisture-Density Characteristics . . . . . Atterberg Limits Measurement of Soil Suction (Filter Paper... Materials . . . 23 Sieve Analysis of Subgrade Materials . . . 24 Optimum Moisture Content and Maximum Dry Density 30 Atterberg Limit of Base and Subgrade Materials Value of Constants A and B for Suction Curves . . 32 41 General Description...

Titus-Glover, Leslie

1995-01-01

49

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

SciTech Connect

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.

Stastna, A., E-mail: astastna@gmail.com [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Sachlova, S.; Pertold, Z.; Prikryl, R. [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Leichmann, J. [Department of Geological Sciences, Faculty of Science, Masaryk University in Brno, Kotlarska 267/2, 611 37 Brno (Czech Republic)

2012-03-15

50

A study of certain elastic and plastic strains induced in flexible pavement systems by repetitive wheel loads  

E-print Network

L)NRARY 1 4 N COLLSQE OF TEXAS A STUDY OF CERTAIN ELASTIC AND PLASTIC STRAINS INDUCED IN FLEXIBLE PAVEMENT SYSTEMS BT REPETITIVE NHEEL LOADS A Thesis By KISSY T. lPTER Submitted to the Graduate School of the Agricultural and Mechanical... College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January, 1959 Major Subject: Civil Engineering A STUDY OF CERTAIN ELASTIC AND PLASTIC STRAINS INDUCED IN FLEXIBLE PAVENENT SYSTENS BY REPETITIVE MEREL...

Meyer, Kirby Thomas

1959-01-01

51

Bituminous pavement recycling Aravind K. and Animesh Das  

E-print Network

Bituminous pavement recycling Aravind K. and Animesh Das Department of Civil Engineering IIT Kanpur Introduction The bituminous pavement rehabilitation alternatives are mainly overlaying, recycling and reconstruction. In the recycling process the material from deteriorated pavement, known as reclaimed asphalt

Das, Animesh

52

A more comprehensive life cycle cost analysis of pavement materials alternatives  

E-print Network

Life Cycle Cost Analysis (LCCA) is a commonly used tool in analyzing the economic viability of highway construction investments. The initial and life-cycle materials costs associated with highway construction involve a ...

Dunn, William Colby

2014-01-01

53

Investigation of mechanical properties of pavement through electromagnetic techniques  

NASA Astrophysics Data System (ADS)

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 of the elasticity measure could be comparable to that of the radar signal. Good agreement were found between high Young modulus values and repaved zones, whereas damaged areas were characterized by lower values of E. Tomographic maps of amplitudes along the z axis were extracted up to a depth of z

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

2014-05-01

54

A study of sound absorption by street canyon boundaries and asphalt rubber concrete pavement  

NASA Astrophysics Data System (ADS)

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 percentage of crumb rubber in the modified binder of the compacted specimens.

Drysdale, Graeme Robert

55

Layer coefficients for NHDOT pavement materials  

NASA Astrophysics Data System (ADS)

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflection in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In situ California bearing ratio (CBR) tests were also conducted. The deflection from the HWD were used with the WESDEF back calculation program to determine the layer moduli. The moduli were than used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in situ CBR and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Janoo, Vincent C.

1994-09-01

56

Evaluation of western shale-oil residue as an additive to petroleum asphalt for use as a pavement crack and joint sealant material  

SciTech Connect

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.

Harnsberger, P.M.; Wolf, J.M.; Robertson, R.E.

1992-11-01

57

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

PubMed

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

Nehls, T; Menzel, M; Wessolek, G

2015-01-01

58

Life cycle assessment of concrete pavements : impacts and opportunities  

E-print Network

The concrete pavement network in the United States plays a crucial role in the economy by enabling the transport of people and goods, but it also leads to resource consumption and environmental impacts. This thesis is ...

Loijos, Alex (Alexander Nikos)

2011-01-01

59

Investigation of Noise and Durability Performance Trends for Asphaltic Pavement Surface Types: Three-Year Results  

E-print Network

Mix Type Rubber Inclusion MPD (micron) Presence of FatigueRubber Inclusion IRI (m/km) MPD (micron) BPN Surface Thickness (mm) Presence of FatigueRubber Inclusion IRI (m/km) MPD (micron) BPN Surface Thickness (mm) Presence of Fatigue

Lu, Qing; Kohler, Erwin R.; Harvey, John T; Ongel, Aybike

2009-01-01

60

A relation of measured deflections, pavement performance and soil characteristics  

E-print Network

moving wheel loads. At the test road sponsored by the "&iestern Association of State Highway Officials in Idaho?i?+ pavement defleotions were studied under ocntrolled traffio oonditions ~ A similar study was made in Virginia on a newly oonstruoted... test road, In California? pavement defleotions were measured on mcvs 4 ments that hsd beer, in ssrvioe for several years ~ Upon observation of the results of these studies ~ whish inoluded a remarkable nor relation between road deflection and road...

Hanna, Daniel Nelson

1957-01-01

61

Development of equations to determine the increase in pavement condition due to treatment and the rate of decrease in condition after treatment for a local agency pavement network.  

E-print Network

DEVELOPMENT OF EQUATIONS TO DETERMINE THE INCREASE IN PAVEMENT CONDITION DUE TO TREATMENT AND THE RATE OF DECREASE IN CONDITION AFTER TREATMENT FOR A LOCAL AGENCY PAVEMENT NETWORK A Thesis by MAITHILEE MUKUND DESHMUKH Submitted... CONDITION DUE TO TREATMENT AND THE RATE OF DECREASE IN CONDITION AFTER TREATMENT FOR A LOCAL AGENCY PAVEMENT NETWORK A Thesis by MAITHILEE MUKUND DESHMUKH Submitted to the Office of Graduate Studies of Texas A&M University in partial...

Deshmukh, Maithilee Mukund.

2010-07-14

62

Adaptive Road Crack Detection System by Pavement Classification  

PubMed Central

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

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

63

Reflectance of interurban-road pavements from radar-based measurements  

NASA Astrophysics Data System (ADS)

Reflectance measurements in interurban-road typical pavements are essential for traffic security. The reflectance of interurban-road pavements presents high variability due to such variables as climatic and atmospheric conditions and the presence of foreign materials on the road (e.g. dirt, fuel or oil). For this reason, the recording of real-time measurements for these kinds of pavements is a complex task. However, its critical importance in traffic safety demands precise measurements under all the possible conditions. In this context, the use of remote-sensing systems working in the radar spectral range is of great interest. With active sensors that receive their own radar signal, the reflectance measurements made by the remote-sensing system are not influenced by the atmospheric conditions. In this work, we present a radar-based methodology to develop real-time measurements of the reflectance in typical interurban-road pavements. We are engaged in extending this new method to study the reflectance of interurban-road pavements within the visible spectrum.

Fernandez, Paz; Peña-García, Antonio; Poyatos-Martínez, David; Escot-Bocanegra, David; Fernández-Oliveras, Alicia

2013-11-01

64

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

NASA Astrophysics Data System (ADS)

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, such voids or moisture, is concerned. The implementation of the horn antenna method is dependent upon, amongst others, the resolution of the antenna in use. The present research work investigates the application of the GPR sensor technique to assess voids within the asphalt layers, with a focus on the air-coupled antenna penetration depth and resolution. For this purpose the dielectric properties of asphalt layer materials were estimated and related voids contents were evaluated based on data collected by an air-coupled GPR system, operating at a 1 GHz and alternatively a 2 GHz central frequency. The collected data is analyzed comparatively for the two antennas. Comparison results indicate differences between the voids determined from the 1 GHz and 2GHz antennas. These differences are further analyzed and evaluated for pavement quality control purposes. The indication of a relationship between the measured voids is also evaluated, while ground truth data is used for the validation of the GPR data analysis results. The above is presented and discussed thoroughly with the aim to assist pavement quality assurance systems

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

2012-04-01

65

Safety considerations for the use of sulfur in sulfur-modified pavement materials  

E-print Network

Construction Co. , Inc. , Indian Village, Louisiana) Schematic does not scale Same ? from screens and j' pug mixer Horizontal Cyclone Dust Collector Water injection Exhaust Scrubber Aggregate fines returned by gravity to hot elevator Fan... irritation due to the fumes. The contractor provided his crew with goggles and 3-M disposal filter masks, which alleviated the problem (11). The emission control system used on the Louisiana project con- sisted of a CEDARAPIDS "Horizontal Cyclone Dust...

Jacobs, Carolyn Yuriko

1980-01-01

66

Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design  

NASA Astrophysics Data System (ADS)

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 ettringite, responsible for sulfate-induced heaving, is also discussed. For Level 2 design of pavements, a total of four stress-based statistical models and two feed-forward-type artificial neural network (ANN) models, are evaluated for predicting resilient modulus of 28-day cured stabilized specimens. Specifically, one semi-log stress-based, three log-log stress-based, one Multi-Layer Perceptrons Network (MLPN), and one Radial Basis Function Network (RBFN) are developed. Overall, semi-log stress-based and MLPN neural network are found to show best acceptable performance for the present evaluation and validation datasets. Further, correlations are presented for stress-based models to correlate Mr with compacted specimen characteristics and soil/additive properties. Additionally, the effect of type of additive on indirect tensile and fatigue characteristics of selected stabilized P- and V-soil is evaluated. This study is based on the fact that stabilized layer is subjected to tensile stresses under wheel loading. Thus, the resilient modulus in tension (M rt), fatigue life and strength in tension (sigmat) or flexure (represented by modulus of rupture, MOR) becomes another important design parameter within the mechanistic framework. Cylindrical specimens are prepared, cured for 28 days and subjected to different stress sequences in indirect tension to study the Mrt. On the other hand, stabilized beam specimens are compacted using a Linear Kneading Compactor and subjected to repeated cycles of reloading-unloading after 28 days of curing in a four-point beam fatigue apparatus for evaluating fatigue life and flexural stiffness. It is found that all three additives improved the Mrt, sigmat and MOR values; however, degree of improvement varied with the type of additive and soil. This study encompasses the differences in the design of semi-rigid pavements developed using AASHTO 1993 and AASHTO 2002 MEPDG methodologies. Further, the design curves for fatigue performance prediction of stabilized layers are developed for different stabilized pavement sections. Knowledge gained f

Solanki, Pranshoo

67

Fatigue properties of rubber modified pavements. Final report  

SciTech Connect

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).

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

1995-05-01

68

International Journal of Road Materials and Pavement Design. V.5., 4, pp. 435-452, 2004.  

E-print Network

Resistance of Asphalt Rubber Mix Versus Hot-Mix Asphalt Michael Mamlouk* and Barzin Mobasher** *Professor 85287, U.S.A. Mamlouk@asu.edu Barzin.mobasher@asu.edu ABSTRACT: Laboratory beam fatigue tests were performed to evaluate the intermediate- and low-temperature fatigue cracking parameters of typical ARM

Mobasher, Barzin

69

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

SciTech Connect

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.

Raad, L.; Saboundjian, S.

1997-05-01

70

PARTIAL-DEPTH REPAIR OF CONCRETE PAVEMENTSCONCRETE PAVEMENTS  

E-print Network

April 2012 PARTIAL-DEPTH REPAIR OF CONCRETE PAVEMENTSCONCRETE PAVEMENTS GUIDE FOR #12;#12;Guide for Partial-Depth Repair of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2 Depth Repair of Concrete Pavements April 2012 6. Performing Organization Code 7. Author(s) 8. Performing

71

The Concrete and Pavement Challenge  

ERIC Educational Resources Information Center

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…

Roman, Harry T.

2012-01-01

72

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

NASA Astrophysics Data System (ADS)

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 electromagnetic mixing (EM) theory, through the utilization of proper models. These models enable the prediction of asphalt mixture density dependent on its bulk dielectric constant as measured by the GPR, the dielectric properties of the asphalt mix materials, as well as other material information. The goal of the present study is to attempt to verify the prediction performance of various density models. To accomplish this goal GPR surveys were carried out in the field during asphalt pavement construction to evaluate the density results due to different compaction modes. The GPR data was analyzed to calculate the appropriate asphalt mix dielectric properties needed for the activation of the considered density prediction models. Predicted densities were compared with densities of the field cores extracted from the as-built asphalt pavement prior to trafficking. It was found that the predicted density values were significantly lower when compared to the ground truth data. A further investigation of the effect of temperature on GPR readings showed that GPR seems to overestimate the in-situ density. However, this approach could be used effectively to evaluate the performance of different compaction methods and set up the compaction pattern that is needed to achieve the desired asphalt pavement density.

Plati, Christina; Georgiou, Panos; Loizos, Andreas

2013-04-01

73

Quantifying mobile and immobile zones during simulated stormwater infiltration through a new permeable pavement material.  

PubMed

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 (?m) and immobile (?im) 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

Bentarzi, Y; Ghenaim, A; Terfous, A; Wanko, A; Poulet, J B

2015-03-01

74

ANDEZT AGREGASININ SICAK KARI?IM ASFALT KAPLAMALARINDA KULLANILAB¯\\/¯ RL¯ˆ¯1¯ N ARA?TIRILMASI INVESTIGATION THE USIBILITY OF ANDESITE AGGREGATE IN HOT MIX ASPHALT PAVEMENTS  

Microsoft Academic Search

More than 95% of asphalt pavement materials consist of aggregates. The aggregates that were used in pavement construction are usually produced from neighborhood aggregate quarries or from natural aggregate sources. Consequently, increasing demands for new aggregate quarries from day to day. In this study, using of andesite rocks in asphalt pavements were investigated as aggregate. For this reason, andesite sample

Hüseyin AKBULUT; Sedat ÇETN; Cahit GÜRER

75

Research of infrared laser based pavement imaging and crack detection  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

76

Development of methodology for detection of defect locations in pavement profile  

E-print Network

in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Dan Zollinger Dallas Little (Chair of Committee... iii ABSTRACT Development of Methodology for Detection of Defect Locations in Pavement Profile. (May 2004) Shubham Rawool, B.E., Goa University Chair of Advisory Committee: Dr. Dan Zollinger Pavement smoothness has become a standard measure...

Rawool, Shubham Shivaji

2005-08-29

77

Dielectric characterization of unstabilized aggregate base materials  

E-print Network

investigates the correlation of dielectric values obtained using the dielectric probe in the laboratory with those calculated from GPR measurements of granular base materials beneath different pavement surfaces in field conditions. The influence of the type...

Guthrie, William Spencer

1999-01-01

78

Application of a New Decision Method in Expressway Pavement Management System  

Microsoft Academic Search

We have proposed the decision-making model of maintenance for cement concrete pavement, by analyzing the formation and evolution characteristics of cement concrete pavement diseases and considering the actual maintenance of Hunan Province, under the thought of preventive maintenance, According to the requirement of preventive maintenance, during the schedule making, we should firstly choose the preventive maintenance measures, such as replace

Jiang-hong Zeng; Jia Xu

2009-01-01

79

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 ...

80

Analysis of Load Stress for Asphalt Pavement of Lean Concrete Base  

NASA Astrophysics Data System (ADS)

The study revealed that whether it is early distresses in asphalt pavement or not depends largely on working performance of base. In the field of asphalt pavement, it is widely accepted that lean concrete base, compared with the general semi-rigid base, has better working performance, such as high strength and good eroding resistance. Problem of early distresses in asphalt pavement, which caused by more traffic loadings, can be settled effectively when lean concrete is used in asphalt pavement. Traffic loading is important parameter used in the analysis of the new pavement design. However, few studies have done extensive and intensive research on the load stress for asphalt pavement of lean concrete base. Because of that, it is necessary to study the load stress for the asphalt pavement. In the paper, first of all, three-dimension finite element model of the asphalt pavement is created for the aim of doing mechanical analysis for the asphalt pavement. And then, the two main objectives of this study are investigated. One is analysis for load stress of lean concrete base, and the other is analysis for load stress of asphalt surface. The results show that load stress of lean concrete base decreases, decrease and increase with increase of base's thickness, surface's thickness and ratio of base's modulus to foundation's modulus respectively. So far as the asphalt surface is concerned, maximum shearing stress, which is caused by load, is evident in asphalt surface which is located in transverse contraction joint of lean concrete base of asphalt pavement. Maximum shearing stress decrease, decrease, decrease and increase respectively with increase of the surface's modulus, the surface's thickness, base's thickness and ratio of base's modulus to foundation's modulus.

Lijun, Suo; Xinwu, Wang

81

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Airport In-Pavement Stationary Runway Weather Information Systems AGENCY: Federal Aviation...Manufacturers of In-Pavement Stationary Runway Weather Information Systems...Passive In- Pavement Stationary Runway Weather Information Systems that meet the...

2011-10-28

82

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

PubMed

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

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

2014-01-01

83

A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement  

PubMed Central

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

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

2014-01-01

84

Thermal cracking of rubber modified pavements, May 1995. Final report  

SciTech Connect

In accordance with the original ISTEA mandate (1991) to use crumb tire rubber in pavements, Alaska would be required to use about 250 tons of used tire rubber starting in 1994 and increasing to about 1,000 tons of rubber in 1997 and each year thereafter. A number of pavements using crumb rubber modifiers have been built in the state and have been in service for periods of 8 to 15 years. Knowledge of the behavior of these rubber-modified pavements under extreme climate conditions, particularly in relation to their low temperature cracking resistance, is necessary for future design and construction of rubberized pavements in Alaska. This report presents results of a study to determine the low temperature cracking resistance of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements.

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

1995-05-01

85

Implications of reliability in mechanistic/empirical pavement design applications  

E-print Network

in Mechanistic/Empirical Pavement Design Applications. (May 1994) Brian Mark Killingsworth, B. S. Texas ASSAM University Chair of Advisory Committee: Dr. Dan G. Zollinger At present there are many design procedures for both asphalt and concrete pavement... probabilistic-based design which evaluates reliability. Zollinger and Lytton state: "Design reliability is an indelible aspect of the pavement design process and needs to be genuinely considered and weighted equally with other design factors included...

Killingsworth, Brian Mark

1994-01-01

86

New structural systems for zero-maintenance pavements. Volume 3: Anchored pavement system designed for Edens Expressway  

NASA Astrophysics Data System (ADS)

The response of the Edens Expressway subjected to mechanical and environmental loads using the anchored pavement concept is discussed. The mechanical and thermal properties of materials that could be encountered in future reconstruction of Edens Expressway are presented in a consistent form for computer programming. These properties are viewed as typical design values during investigation of pavement response. The behavior of the anchored pavement under induced temperature loads and weakening of subgrade (by thawing action) is clearly demonstrated. The example problem provides the input parameters of materials and loads for the analysis, the generation of finite element mesh, and the results of the analysis.

Saxena, S. K.; Militsopoulos, S. G.

1980-08-01

87

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

Code of Federal Regulations, 2010 CFR

...depreciate the use of spectrophotometers or accurate tristimulus colorimeters for measuring the daytime color of retroreflective materials...determined that 0/45 or 45/0 spectroradiometers and tristimulus colorimeters have proved that the measurements can be considered...

2010-04-01

88

Asphalt Oxidation Kinetics and Pavement Oxidation Modeling  

E-print Network

Most paved roads in the United States are surfaced with asphalt. These asphalt pavements suffer from fatigue cracking and thermal cracking, aggravated by the oxidation and hardening of asphalt. This negative impact of asphalt oxidation on pavement...

Jin, Xin

2012-07-16

89

COLORADO DEPARTMENT OF TRANSPORTATION Sustainability of Concrete Pavement  

E-print Network

COLORADO DEPARTMENT OF TRANSPORTATION Sustainability of Concrete Pavement I-225 - Mississippi to 6 · 2 Mile Reconstruction Existing: · 4 Lane Divided Highway · 8" Concrete Pavement (Recycled on-site) · 4" Asphalt Overlay (Recycled off-site) Project Design: · 6 Lane Divided Highway · 13" Concrete

90

Field observations and numerical models of GPR response from vertical pavement cracks  

NASA Astrophysics Data System (ADS)

High resolution ground-coupled GPR is useful for determining thickness, deterioration, jointing and cracks in pavements. Although only millimetres in width, vertical cracks can present a significant target in reflection profiles. On composite pavements, consisting of asphalt over concrete, we have observed responses at locations above joints in the underlying concrete that we attribute to cracks within the asphalt layer. On some asphalt pavement, we observed significantly stronger diffraction and waveguide effects responses at a 250 MHz centre frequency rather than at 1000 MHz, despite the small crack apertures. Using numerical modelling we show the importance of crack filling material, crack aperture, crack height, asphalt conductivity and the GPR centre frequency on the observed response. Our observations and models clearly show the potential of GPR to detect and characterise vertical cracks. We recommend a multi-frequency approach to GPR surveys of pavement: high frequency for crack characterisation and lower frequency for crack detection.

Diamanti, Nectaria; Redman, David

2012-06-01

91

Reducing traffic noise with quieter pavements  

NASA Astrophysics Data System (ADS)

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.

Donavan, Paul

2005-09-01

92

Laboratory evaluation of selected syncrude products and upgraded by-products as pavement recycling agents. Final report, Part II  

SciTech Connect

Based on the information presented in this report, the following conclusions appear warranted: (1) Selected syncrude products and upgraded by-products have the potential for use as recycling agents for asphalt pavements. The syncrude recycling agents exhibited about the same performance as selected commercially produced recycling agents. (2) When recycled mixtures were aged at temperatures of 33, 77, 140 and 250/sup 0/F, the mixtures containing the syncrude recycling agents performed about the same as those containing the conventional recycling agents and produced acceptable mixtures from the standpoint of durability. (3) Syncrude recycling agents require about the same period of time to interact with the aged binder as the conventional recycling agents. A substantial portion of the softening action of a recycling agent should be complete after a hot recycled mixture has been mixed, transported, placed and compacted in the field. (4) Tensile properties at -12, 0 and 33/sup 0/F of the recycled mixtures containing the syncrude recycling agents are quite similar to tensile properties of virgin mixtures tested under similar conditions. (5) Fatigue performance of the mixtures containing the syncrude recycling agents compared favorably with performance of other recycled mixtures containing commercially available recycling agents and conventional asphalt concrete paving mixtures. (6) Mixtures containing the syncrude recycling agents exhibited about the same range of creep compliance and permanent deformation values as other recycled mixtures containing commercially available recycling agents and conventional asphalt concrete paving mixtures. 11 references, 25 figures, 3 tables.

Button, J.W.

1984-08-01

93

Cosmogenic 3 He surface-exposure dating of stone pavements  

E-print Network

and pedogenic modification of windblown dust. In-situ cosmogenic 3 He surface-exposure ages on volcanic volcanic bedrock, are indistinguishable at the 1 level. We conclude that stone pavements are born of windblown sediments, not deflation or water erosion, is the major agent of pavement evo- lution. According

Ahmad, Sajjad

94

Leaching of organic contaminants from storage of reclaimed asphalt pavement  

Microsoft Academic Search

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

Malin Norin

2004-01-01

95

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

PubMed

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

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

2013-03-01

96

CHECKLIST FOR INSPECTION OF POROUS PAVEMENTS Location: Inspector  

E-print Network

for ice management S U Piles of accumulated salt removed in spring S U 2. Debris Cleanup (2-4 times a year minimum, Spring & Fall) Clean porous pavement to remove sediment and organic debris on the pavement available) S U 3. Controlling Run-On (2-4 times a year) Adjacent vegetated areas show no signs of erosion

97

Improvement of canny algorithm based on pavement edge detection  

Microsoft Academic Search

In this paper we introduce an improved Canny edge detection algorithm and an edge preservation filtering procedure for pavement edge detection applications. Data of pavement images were randomly selected to test this algorithm. There are some problems of Canny operator, unable to detect the weak edge and distinguish the grayscale with little change, the detected edge uncontinuous. Based on these

Huili Zhao; Guofeng Qin; Xingjian Wang

2010-01-01

98

Significance of bearing capacity of clayey subgrade in flexible pavement design  

Microsoft Academic Search

Clays as subgrades pose serious problems to flexible pavements built over them as they retain moisture for a longer period and possess low strength. Excessive settlements along the wheel tracks on pavement surface and bearing capacity failures in the subgrade soil are often observed in the flexible pavements constructed over such subgrades. So, the present status of flexible pavements in

C. N. V. Satyanarayana Reddy; N. V. Rama Moorthy

2005-01-01

99

Geotextiles in Flexible Pavement Construction  

ERIC Educational Resources Information Center

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…

Alungbe, Gabriel D.

2004-01-01

100

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...

101

Development of a Prediction Model for Skid Resistance of Asphalt Pavements  

E-print Network

surface. Microtexture is influenced by aggregate surface characteristics and is required to disrupt the continuity of surface water film and attain frictional resistance between the tire and the pavement surface. Macrotexture is affected mostly by mixture...

Rezaei, Arash

2012-02-14

102

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)

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 samples in laboratory. In parallel numerical simulations have been used to generate a set of time sequence of thermal maps for simulated samples with and without subsurface defect. Using this set of experimental and simulated data different approaches (thermal contrast, FFT analysis, polynomial interpolation, singular value decomposition…) for defect location have been studied and compared. Defect depth retrieval was also studied on such data using different thermal model coupled to a direct or an inverse approach. Trials were conducted both with an uncooled and cooled infrared camera with different measurement performances. Results obtained will be discussed and analysed in the paper we plan to present. Finally, combining numerical simulations and experiments allows us discussing on the sensitivity influence of the infrared camera used to detect subsurface defects.

Dumoulin, Jean; Ibos, Laurent

2010-05-01

103

Measurements of the stiffness and thickness of the pavement asphalt layer using the enhanced resonance search method.  

PubMed

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

Zakaria, Nur Mustakiza; Yusoff, Nur Izzi Md; Hardwiyono, Sentot; Nayan, Khairul Anuar Mohd; El-Shafie, Ahmed

2014-01-01

104

Effect of pervious and impervious pavement on the rhizosphere of American Sweetgum (Liquidambar styraciflua)  

E-print Network

Mature trees help to offset urban area problems caused by impervious pavement. Trees in paved areas remain unhealthy due to a poor root zone environment. The objective of this experiment was to test if soil under pervious concrete, with greater...

Viswanathan, Bhavana

2012-07-16

105

Micro-topographic analysis of shell pavements formed by aeolian transport in a wind tunnel simulation  

NASA Astrophysics Data System (ADS)

Beach surfaces containing shell materials represent one end-member of a range of environments in which armoring is the primary control on wind erosion. Unlike spheres and cylinders which have formed the basis of theoretical model formulation and much of the early work in wind tunnels, mollusc shells have complex and non-uniform shapes which vary with their orientation. Identification of shell perimeter, height and frontal area relative to the bed area (roughness density) is therefore a formidable task, but nonetheless is essential for modeling sediment entrainment from beach surfaces. A methodology is suggested in this paper for capturing and analyzing these geospatial data, in the context of a wind tunnel simulation designed to improve understanding of the geophysical processes involved in armoring. For deposits where non-erodible shells represent half of the volume of the parent material, the surface appears to be highly stable to wind erosion from the outset, although minor reworking of the intervening, erodible sediment does occur. In comparison, the shell coverage must increase to approximately 30% during wind erosion events in order for any given beach surface to stabilize, especially beach deposits with a low concentration of shells by volume. With suitable calibration, the Raupach shear stress partitioning model can be forced to perform well in predicting the threshold conditions for particle entrainment. However, this approach overlooks the pivotal involvement of particle impact and ricochet in the creation and sculpting of the armored bed. As a case in point, when the shells are removed from digital elevation models of armored beach surfaces formed in aeolian systems, the adjusted topography is not suggestive of the presence of coherent flow structures (e.g., horseshoe vortices and wedge shaped shelter areas) as assumed to exist in the stress partitioning approach for isolated flows. This would suggest that future work on the armoring of natural surfaces affected by wind erosion must allow for more complexity in the flow perturbation.

McKenna Neuman, Cheryl; Li, Bailiang; Nash, David

2012-12-01

106

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...

107

A utility evaluation of nondestructive testing devices used on asphalt concrete pavements  

E-print Network

A UTILITY EVALUATION OF NONDESTRUCTIVE TESTING DEVICES USED ON ASPHALT CONCRETE PAVEMENTS A Thesis by SHELLEY MARIE STOFFELS Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1986 Major Subject: Civil Engineering A UTILITY EVALUATION OF NONDESTRUCTIVE TESTING DEVICES USED ON ASPHALT CONCRETE PAVEMENTS A Thesis by SHELLEY MARIE STOFFELS Approved as to style and content by: Robe L. Lytt red...

Stoffels, Shelley Marie

1986-01-01

108

Identification of asphalt binder properties that affect cracking performance of hot mixed asphalt concrete pavements  

E-print Network

fulfillment of the requirements for the degree of MASTER OF SCIENCE May l997 Major Subject. Civil Engineering IDENTIFICATION OF ASPHALT BINDER PROPERTIES THAT AFFECT CRACKING PERFORMANCE OF HOT MIXED ASPHALT CONCRETE PAVEMENTS A Thesis by CHARLES.... Bradley (Member) Ignacio Rodri ez turbe (Head of Department) May 1997 Major Subject: Civil Engineering ABSTRACT Identification of Asphalt Binder Properties That Affect Cracking Performance of Hot Mixed Asphalt Concrete Pavements. (May 1997...

Hastings, Charles Patrick

1997-01-01

109

Surface control of desert pavement pedologic process and landscape function, Cima Volcanic field,  

E-print Network

Surface control of desert pavement pedologic process and landscape function, Cima Volcanic field of the land surfaces it mantles. Surface clasts protect underlying sediments and soil from removal by wind

Ahmad, Sajjad

110

Development and implementation of an enhanced procedure for estimating pavement rehabilitation and maintenance expenditures  

E-print Network

with critical values of performance. 3. Calculation of Survival Parameters. The time elapsed until a new pavement section needs a major rehabilitation is known as the service life of the pavement. The statistical distribution of the service life is referred... specified time. The time elapsed until a new pavement section needs a major rehabilitation, or the time between major rehabilitations for an existing pavement section, is known as the service life of the pavement. The statistical distribution...

Garcia-Diaz, Juan Carlos

1987-01-01

111

Oxidative reactions and their impact on the properties of asphalt as a pavement binder  

E-print Network

of MASTER OF SCIENCE December 1991 Major Subject: Chemical Engineering OXIDATIVE REACTIONS AND THEIR IMPACT ON THE PROPERTIES OF ASPHALT AS A PAVEMENT BINDER A Thesis by CHEE KEUNG LAU Approved as to style and content by: Charles J. over (Chair... of Committee) Rich d R. Davison (Member) i ( Alan Letton (Member) Raymond W. umerfelt (Head of Department) December, 1991 111 Oxidative Reactions and Their Impact on the Properties of Asphalt as a Pavement Binder. (December 1991) Chee Keung Lau, B...

Lau, Chee Keung

1991-01-01

112

The evaluation of airfield pavements  

E-print Network

- dams, or combinations of these, Assembly arrangements are either trioycle or bicycle. Evaluations are made for each type of gear configuration and assembly arrangement within a range of loading of the ourrent operational aircraft, This is shown..., Twin-tandem-wheel Assembly, Tricycle, spacing 9-18-9 x 27, 49-sq. -in. contact area 20-100 Twin-wheel Assembly, Bicycle, spacing 37 in. , 267-sq. -in. contact, area 55-140 Twin-tvin-wheel Assembly, Bicycle, spacing 37 x 62 x 37, 267-sq. -in...

Poor, Arthur Reginald

1960-01-01

113

Clogging evaluation of open graded friction course pavements tested under rainfall and heavy vehicle simulators.  

PubMed

In this study a new procedure is developed to obtain core samples from field sections to assess clogging mechanisms of open graded friction course (OGFC) pavements using X-ray computed tomography (CT) imaging. The approach compared X-ray computed tomography (CT) images taken before and after: (1) rainfall simulations without trafficking to investigate particle-related clogging and (2) full-scale accelerated pavement rutting tests (APT) to investigate deformation related clogging of OGFC layers. Rainfall simulations were performed with runoff water of known total suspended solids (TSS) and particle size distributions (PSDs). Full-scale accelerated rutting tests were performed under controlled temperature and loads. Both investigations were performed for three different OGFC pavements with different layer thicknesses and mix types. The clogging of rutting test sections were also evaluated by comparing the surface permeability measurements performed before and after APT testing. The results of X-ray CT image processing revealed a significant reduction in air-void content of core samples after APT rutting tests. The highest air-void reduction was concentrated at the bottom of the OGFC layers. Permeability measurements also showed a 40%-90% reduction in permeability after APT trafficking. X-ray CT image processing of core samples tested under simulated rainfall showed that air void content reduction is concentrated in the lower part (2-6 mm from the bottom) of the OGFC layers as a result of particle accumulation. Small changes in air void contents were observed in the upper part of the OGFC layers (10-15 mm) while these reductions in air void contents were not significant to cause surface overflow and hence it is expected that the tested OGFC pavements will have sufficient permeability to infiltrate water during most average storm events. PMID:23920417

Coleri, Erdem; Kayhanian, Masoud; Harvey, John T; Yang, Kai; Boone, John M

2013-11-15

114

Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?  

PubMed

Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300?m). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. PMID:25618819

Nichols, Peter W B; White, Richard; Lucke, Terry

2015-04-01

115

Research on the Maintenance Decision-Making of Cement Concrete Pavement Based on Preventive Maintenance  

Microsoft Academic Search

The cement concrete pavement maintenance decision-making model has been proposed, by analyzing the formation and development characteristics of pavement diseases and considering the actual maintenance in Hunan Expressway. The maintenance decision-making tree and the decision-making progress have been established in order to realize the purpose of rational distribution of maintenance funds and improve maintenance quality, under the thought of preventive

Jian Zhao; Jia Xu

2009-01-01

116

The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment  

Microsoft Academic Search

Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption has been hindered by a lack of detailed knowledge of their hydrological performance. This paper describes a research programme that produced detailed information on the hydrological behaviour of a car park surface. The study involved the construction of full-scale permeable pavement

C. T. Andersen; I. D. L. Foster; C. J. Pratt

1999-01-01

117

Investigation and application of fractured slab techniques for PCC pavements. Final report, May 1996--April 1999  

SciTech Connect

Slab fracture techniques, including break and seat, crack and seat, and rubblization have in recent years gained widespread recognition among pavement engineers as means for eliminating or substantially reducing the potential for reflective cracking in hot mix asphalt (HMA) overlays over portland cement concrete (PCC) pavements. Guidelines for the use of these techniques in Wisconsin, however, have not been clearly established. This reports examines the PCC rehabilitation techniques of rubblization and crack and seat used in Wisconsin and their performance. The report examines the literature and evaluates the critical issues associated with the use of PCC fracture techniques by various agencies. Several elements pertinent to fracture techniques are also identified and incorporated in a database for in-service fractured overlaid PCC pavements in Wisconsin. In addition, the in-service performance of cracked and seated and rubblized pavements in Wisconsin is evaluated.

Owusu-Ababio, S.; Nelson, T.

1999-04-01

118

AUTOMATED PAVEMENT IMAGING PROGRAM (APIP) FOR PAVEMENT CRACKS CLASSIFICATION AND QUANTIFICATION - A PHOTOGRAMMETRIC APPROACH  

Microsoft Academic Search

The evaluation of pavement conditions is an important part of pavement management. Traditionally, pavement condition data are gathered by human inspectors who walk or drive along the road to assess the distresses and subsequently produce report sheets. This visual survey method is not only time consuming and costly but more importantly it compromises the safety of the field personnel. With

M. Mustaffar; T. C. Ling

1998-01-01

119

Automated pavement crack detection  

E-print Network

AUTOMATED PAVEMENT CRACK DETECTION A Thesis by ASHOK MADHAVA RAO Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject...: Electrical Engineering AUTOMATED PAVEMENT CRACK DETECTION A Thesis by ASHOK MADHAVA RAO Approved as to style and content by . c Norman C. Grisw d (Chair of Committ ) Nasser Kehtarnavaz (Member) g, J~, Karan Watson Robert L. Lytt (Member) Jo W...

Rao, Ashok Madhava

1991-01-01

120

Use of lug anchors to related pavement movement  

NASA Astrophysics Data System (ADS)

Minnesota Department of Transporatation's policy is that grades in the 3 to 5 percent and greater range are steep and may require lug anchors. Standard lug anchor spacing varies from 150 feet, center to center, for 3 percent grades to 75 feet, center to center, for 5 percent and greater grades. Conclusions are: (1) that lug anchors do prevent the downhill movement of the concrete pavement; (2) that when lug anchors are used a perforated pipe system also be built to collect the surface water that enters the pavement structure thus eliminating the anticipated base pumping and pavement settlement.

Oakey, S. A.

1980-04-01

121

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

122

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

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

123

4/28/2010 1Porous Pavements Porous Pavements  

E-print Network

4/28/2010 1Porous Pavements Porous Pavements for Stormwater Restoration in Urban Environments Cliff Aichinger Ramsey-Washington Metro Watershed District #12;4/28/2010 2Porous Pavements Porous Pavements Why am new volume reduction rules. Porous pavement is one of a relative few BMPs that address stormwater

Minnesota, University of

124

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)

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

Plati, Christina; Loizos, Andreas

2013-10-01

125

Variability of hot mix asphalt produced with reclaimed asphalt pavement  

E-print Network

of natural resources (aggregate, binder and energy). Adequate techniques to assess the variability of Reclaimed Asphalt Pavement (RAP) are lacking. The objectives of this research are to determine the variabilities of RAP and Hot Mix Asphalt (HMA), determine...

Yang, Guiqin

1999-01-01

126

Systematic Conversion of Single Walled Carbon Nanotubes into n-type Thermoelectric Materials by Molecular Dopants  

PubMed Central

Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. ?4.4?eV and ca. ?5.6?eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules. PMID:24276090

Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

2013-01-01

127

Systematic conversion of single walled carbon nanotubes into n-type thermoelectric materials by molecular dopants.  

PubMed

Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. -4.4 eV and ca. -5.6 eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules. PMID:24276090

Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

2013-01-01

128

Systematic Conversion of Single Walled Carbon Nanotubes into n-type Thermoelectric Materials by Molecular Dopants  

NASA Astrophysics Data System (ADS)

Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. -4.4 eV and ca. -5.6 eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules.

Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

2013-11-01

129

Mechanical analysis of a mixed mode debonding test for "composite" pavements A. Chabot*, M. Hun, F. Hammoum  

E-print Network

of UltraThin White-topping pavements (UTW) [1-3] or near reflective cracks of composite pavement [4] during uniformly distributed over a rectangular area at the edge of a joint on an Ultra Thin Whitetopping pavement

Paris-Sud XI, Université de

130

Material Hardship and Child Socioemotional Behaviors: Differences by Types of Hardship, Timing, and Duration.  

PubMed

Child behavior problems are associated with long-term detrimental effects. A large body of literature looks at the association between income and child behavior but few studies examine this association with material hardship, an alternative economic indicator. We use data from the Fragile Families and Child Wellbeing Study to examine the following questions: (a) Is material hardship associated with child socioemotional behavior and are there differences by developmental timing, (b) Are particular hardships (bills, utilities, food, housing, medical) more strongly associated with child behavior, and (c) Are there differences in the association between short-term and long-term material hardship and child behavior? We find that children in households experiencing material hardship score significantly higher on externalizing and internalizing behaviors. Additionally, we find that a mother's inability to pay bills, experience of utility interruption, and housing instability are adversely related to child behavior. We also find that the association between material hardship and child behaviors is stronger at age 5 and that chronic aggregate hardship has a stronger association with child behavior. PMID:22408284

Zilanawala, Afshin; Pilkauskas, Natasha V

2012-04-01

131

Material Hardship and Child Socioemotional Behaviors: Differences by Types of Hardship, Timing, and Duration  

PubMed Central

Child behavior problems are associated with long-term detrimental effects. A large body of literature looks at the association between income and child behavior but few studies examine this association with material hardship, an alternative economic indicator. We use data from the Fragile Families and Child Wellbeing Study to examine the following questions: (a) Is material hardship associated with child socioemotional behavior and are there differences by developmental timing, (b) Are particular hardships (bills, utilities, food, housing, medical) more strongly associated with child behavior, and (c) Are there differences in the association between short-term and long-term material hardship and child behavior? We find that children in households experiencing material hardship score significantly higher on externalizing and internalizing behaviors. Additionally, we find that a mother's inability to pay bills, experience of utility interruption, and housing instability are adversely related to child behavior. We also find that the association between material hardship and child behaviors is stronger at age 5 and that chronic aggregate hardship has a stronger association with child behavior. PMID:22408284

Zilanawala, Afshin; Pilkauskas, Natasha V.

2012-01-01

132

Development of a mult-objective strategic management approach to improve decisions for pavement management practices in local agencies  

E-print Network

network pavement condition index (PCI), average network remaining life, percent of the pavement network in good condition, and percent of the pavement network in poor and very poor condition. Results from a case study show that funding allocation methods...

Chang Albitres, Carlos Martin

2009-05-15

133

ROUGH THIN PAVEMENT THICKNESS ESTIMATION BY GPR N. Pinel, L. Liu, C. Bourlier, Y. Wang  

E-print Network

ROUGH THIN PAVEMENT THICKNESS ESTIMATION BY GPR N. Pinel, L. Liu, C. Bourlier, Y. Wang IREENA radar (GPR) is a useful means of me- dia sounding, which is widely used at centimeter-scale wave domain of this approximation, and its influence on the electromagnetic backscattering and on the GPR

Paris-Sud XI, Université de

134

Cracks in desert pavement rocks: Further insights into mechanical weathering by directional insolation  

E-print Network

Cracks in desert pavement rocks: Further insights into mechanical weathering by directional Fractures The formation of cracks is a fundamental first step in the physical weathering of rocks in desert not readily attributable to rock anisotropies or shape) in boulders or cobbles form due to tensile stresses

Ahmad, Sajjad

135

Incorporating uncertainty in the Life Cycle Cost Analysis of pavements  

E-print Network

Life Cycle Cost Analysis (LCCA) is an important tool to evaluate the economic performance of alternative investments for a given project. It considers the total cost to construct, maintain, and operate a pavement over its ...

Swei, Omar Abdullah

2012-01-01

136

GPR abilities in investigation of the pavement transversal cracks  

NASA Astrophysics Data System (ADS)

This paper describes the results of an investigation into the capabilities of the GPR technique within the field of pavement crack diagnostics. Initially, laboratory tests were performed on prototypes simulating idealized cracks. Next, long-term visual observation and repeated GPR scanning were performed, on three roads of semi-rigid construction, several hundreds of meters long and subjected to heavy traffic. Furthermore, a road of rigid construction was tested, having a more than 70-year history of use. In several cases the cracks were probed by drillings, in order to recognize structures responsible for signal generation, or to explain reasons of signal lacking. The main result of this work is a list of GPR indications of cracks, which can be noticed on echograms. It was created through a correlation of the visually-observed cracks with the corresponding echograms, with decimeter accuracy. Several types of GPR responses were classified and linked to possible categories of crack structures, or to processes associated with the presence of cracks (as crumbling, erosion, and lithological alterations). The poor visibility of cracks was also studied, due to small crack size, or to the blurred character of the damaged area, or else to masking effects related to coarse grains in the asphalt mixture. The efficiency of the proposed method for the identification and localization of cracks is higher when a long-term GPR observation is performed.

Krysi?ski, Lech; Sudyka, Jacek

2013-10-01

137

Rehabilitation of continuously reinforced concrete pavements using overlays  

E-print Network

was actually experienced. Any rehabilitation alternative being considered must, hence be able to meet the design requirements and not fail during its design life. Rigid overlays provide a feasible option in terms of strength and longevity. For a nation... whose network of pavements is now in need of rehabilitation, CRC pavements present themselves as a very feasible and lucrative option, if life-cycle costs were the basis of design. If designed and constructed properly, CRC overlays can serve...

Sriraman, Soumya

1993-01-01

138

Preventive Maintenance Condition Standards of Expressway Asphalt Pavement  

Microsoft Academic Search

There isn't a unified pavement preventive maintenance road condition standard both at home and abroad till now, in view of that, macro and micro road condition standard for expressway asphalt pavement preventive maintenance is established, among which macro standard is under the promise of PSSIges83, and is under the control standard of 82lesPCI<88, 88lesRQI<93, 85lesSRI<90. Its determinative process, the usage

Hu Guoxiang; Li Jie

2009-01-01

139

Removal of formaldehyde from indoor air by passive type air-cleaning materials  

Microsoft Academic Search

We have developed a board-like air-cleaning material consisting of activated carbon particles and manganese oxides, by which HCHO gas is decomposed into carbon dioxide even at room temperature. In this study, we investigated removal efficiencies of the air-cleaning board in a passive mode using a kinetic approach. First-order removal rate constant, k, corresponding to air change rate was characterized for

Yoshika Sekine; Atsushi Nishimura

2001-01-01

140

PZT active health monitoring for fatigue accumulative damage of concrete beam containing nano-particles for pavement  

Microsoft Academic Search

Based on the actuation and sense function of piezoceramic materials, PZT active health monitoring for fatigue accumulative damage of concrete beam containing nano-particles (TiO2) for pavement is experimentally studied. The test results indicate that the vibration signals received by PZT patches have three development stages obviously: the damage-formation stage, the damage-steady-growth stage and the damage-sharp-growth stage, which shows that PZT

Mao-hua Zhang; Hui Li; Jin-ping Ou

2007-01-01

141

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

PubMed

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

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

2014-01-01

142

An Overview Of Pavement Management System For Industrial Areas  

NASA Astrophysics Data System (ADS)

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.

Hokam, Vivek S.

2012-03-01

143

Adaptive prediction of pavement performance  

E-print Network

(3) Cracking Log?(p?) = a, + ' +a, x(d?+a, )+a, xLog?(E, o) d. +a, Log?(P, ) = a, + a, xLog?(E, ) + a, xLvg, ?(d. +a, ) where, p, , P, . = parameters of the sigmoidal curve for cracking d, = overlay thickness, inches Eso = subgrade modulus, psi... (referred to as coefficient "o") t = log, ( I / age ) a, b, c = model coefficients Depending on the model coefficients, the curve can be a straight line, convex, concave or S-shaped with various degrees of curvature Individual distresses are predicted...

Zulyaminayn, Mohammed

2002-01-01

144

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

SciTech Connect

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.

G.A. Valentine; C.D. Harrington

2005-08-10

145

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

SciTech Connect

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.

G.A. Valentine; C.D. Harrington

2005-08-26

146

Use of recycled materials in highway construction. Final report  

Microsoft Academic Search

The major objectives of this study were to examine: (1) the types of recycled materials that are appropriate and feasible as alternative paving materials, such as glass and tires; and (2) the types of recycled materials, such as mixed-plastics and compost, that can be utilized in all types of transportation applications other than pavements. Seven key products are investigated: (1)

D. L. Swearingen; N. C. Jackson; K. W. Anderson

1992-01-01

147

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

NASA Astrophysics Data System (ADS)

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 from 5 mm to 25 mm. Model testing shows total event discharge simulated well, although low Nash-Sutcliffe coefficients for events indicate a poor fit between the shape and timing of the modeled and monitored hydrograph, which we attribute to poor characterization of friction factors in urban catchments. Scenario-based model analysis tested catchment response to substitution of pervious for conventional pavement by percent and pavement-function scenarios. Results are consistent with previous findings in that short duration-high intensity storms trigger threshold infiltration capacity, past which pervious pavement damping of runoff volume levels off, approaching conventional levels. However at the modeled catchment scale, this initial damping represents a significant reduction in volume, peak flow velocity, and contaminant loading potential. Urban surface drainage networks concentrate and channel flow along roads: the capacity of pervious pavements to simultaneously increase infiltration directly at location of greatest runoff and mitigate inflow effects from remote points has compelling potential as a hydrologic and urban systems engineering tool.

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

2011-12-01

148

Research on tensile strength characteristics of bridge deck pavement bonding layers  

NASA Astrophysics Data System (ADS)

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.

Wu, Shaopeng; Han, Jun

2010-03-01

149

Determination of the Presence Conditions of Pavement Markings using Image Processing  

E-print Network

Pavement markings, as a form of traffic control devices, play a crucial role in safely guiding drivers. Restriping pavement markings is an important task in the maintenance of traffic control devices. Every year state agencies spend a lot of money...

Ge, Hancheng

2012-10-19

150

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

NASA Astrophysics Data System (ADS)

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.

Kowalski, Karol J.

151

Experimental pavement delineation treatments  

NASA Astrophysics Data System (ADS)

Visibility and durability of materials used to delineate shoulders and medians adjacent to asphalt pavements were evaluated. Materials evaluated were polysulfide and coal tar epoxies, one and two component polyesters, portland cement, acrylic paints, modified-alkyd traffic paint, preformed plastic tape, and thermoplastic markings. Neat applications, sand mortars, and surface treatments were installed in several geometric patterns including cross hatches, solid median treatments, and various widths of edge lines. Thermoplastic pavement markings generally performed very well, providing good visibility under adverse viewing conditions for at least 4 years. Thermoplastic 4 in. wide edge lines appear to provide adequate visibility for most conditions.

Bryden, J. E.; Lorini, R. A.

1981-06-01

152

Rutting and drainage design methodology for a concrete block pavement  

E-print Network

procedure provides a measure of the pavement's performance by predicting the amount of rutting. This thesis also presents the analysis of the structural performance of a concrete block pavement that was constructed at Texas A&M's Riverside campus...

Poduska, Daryl Jason

1998-01-01

153

The use of reflective and permeable pavements as a potential practice for heat island mitigation and stormwater management  

NASA Astrophysics Data System (ADS)

To help address the built environmental issues of both heat island and stormwater runoff, strategies that make pavements cooler and permeable have been investigated through measurements and modeling of a set of pavement test sections. The investigation included the hydraulic and thermal performance of the pavements. The permeability results showed that permeable interlocking concrete pavers have the highest permeability (or infiltration rate, ˜0.5 cm s-1). The two permeable asphalt pavements showed the lowest permeability, but still had an infiltration rate of ˜0.1 cm s-1, which is adequate to drain rainwater without generating surface runoff during most typical rain events in central California. An increase in albedo can significantly reduce the daytime high surface temperature in summer. Permeable pavements under wet conditions could give lower surface temperatures than impermeable pavements. The cooling effect highly depends on the availability of moisture near the surface layer and the evaporation rate. The peak cooling effect of watering for the test sections was approximately 15-35?°C on the pavement surface temperature in the early afternoon during summer in central California. The evaporative cooling effect on the pavement surface temperature at 4:00 pm on the third day (25 h after watering) was still 2-7?°C lower compared to that on the second day, without considering the higher air temperature on the third day. A separate and related simulation study performed by UCPRC showed that full depth permeable pavements, if designed properly, can carry both light-duty traffic and certain heavy-duty vehicles while retaining the runoff volume captured from an average California storm event. These preliminarily results indicated the technical feasibility of combined reflective and permeable pavements for addressing the built environment issues related to both heat island mitigation and stormwater runoff management.

Li, H.; Harvey, J. T.; Holland, T. J.; Kayhanian, M.

2013-03-01

154

RESEARCH Open Access Pavement crack characteristic detection based  

E-print Network

are not caused by pavement distress such as tire marks, oil spills and shadows. In the field of 3D pavement crack distress such as tire marks, oil spills, shadows, and recent fillings [11]. Moreover, the shadows and poor

Joensuu, University of

155

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...

156

Extended wavelength InGaAs infrared detector arrays based on three types of material structures grown by MBE  

NASA Astrophysics Data System (ADS)

Extended wavelength InGaAs infrared detector arrays in 1.0~2.5?m spectral rang based on three types of material structures grown by MBE were studied. The first type InGaAs detectors, marked by sample 1#, were fabricated using Pi- N epitaxial materials, mesa etching technique, side-wall and surface passivating film. The second type InGaAs detectors, marked by sample 2#, were fabricated using N-i-P epitaxial materials, mesa etching technique, side-wall and surface passivating film. The third type InGaAs detectors, marked by sample 3#, were fabricated using n-i-n epitaxial materials, planar diffusion process and surface passivating coating. I-V curves, low frequency noise and response spectra of these detectors were measured at the different temperature. The response spectra of these detectors cover 1.0~2.5?m wavelength range. The dark current density of three types InGaAs detectors are 28nA/cm2, 2?A/cm2, 9?A/cm2 at 200K and -10mV bias voltage, respectively. Compared to Sample 2# and Sample 3#, sample 1# presents the lower dark current at the same temperature and the same bias voltage, which mainly results in the improvement of surface passivation film and the depth of mesa etching. The frequency spectrum of the noise of sample 1# has an inflection point at about 10Hz frequency, 1/f noise play an obviously role in the detectors below the 10Hz frequency.

Gong, Haimei; Li, Xue; Li, Tao; Tang, Hengjing; Shi, Ming; Shao, Xiumei; Zhang, Yonggang

2014-06-01

157

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

SciTech Connect

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.

Santero, Nicholas; Masanet, Eric; Horvath, Arpad

2010-04-20

158

Simulated aircraft load testing and non-destructive evaluation of bituminous pavements  

Microsoft Academic Search

The US Federal Aviation Administration's National Airport Pavement Test Facility was constructed to generate full-scale accelerated pavement test data for the development of advanced airport pavement design criteria. During the first round of traffic testing, a six-wheel (Boeing 777) landing gear and a four-wheel (Boeing 747) landing gear were trafficked on flexible test pavements until they were deemed failed. Non-destructive

Kasthurirangan Gopalakrishnan; Marshall R. Thompson

2008-01-01

159

of Transportation Rigid Pavement Design and Analysis Web-Based Training Site  

E-print Network

Texas Department of Transportation Rigid Pavement Design and Analysis Web-Based Training Site Highway Administration Texas Department of Transportation, 2004 Rigid Pavement Design and Analysis Web for six computer programs pertaining mainly to the design and analysis of rigid pavements. The programs

Texas at Austin, University of

160

Determination of nitroaromatic and nitramine type energetic materials in synthetic and real mixtures by cyclic voltammetry.  

PubMed

Nitro-explosives contain reducible aromatic -NO2 groups or cyclic >N-NO2 bonds that may undergo reductive cleavage. This work reports the development of a cyclic voltammetric (CV) assay for nitro-aromatics (trinitrotoluene (TNT), dinitrotoluene (DNT)) and nitramines (1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)) using a glassy carbon electrode. This determination was first used for these energetic materials by resolving current responses of reduction potentials primarily due to one constituent but partly contributed by other constituents. Calibration curves of current intensity versus concentration were linear in the range of 30-120 mg L(-1) for RDX with a limit of detection (LOD) of 10.2 mg L(-1), 40-120 mg L(-1) for HMX (LOD=11.7 mg L(-1)), 40-120 mg L(-1) for TNT (LOD=11.2 mg L(-1)), and 40-140 mg L(-1) for DNT (LOD=10.8 mg L(-1)). Results showed that the CV method could provide a sensitive approach for the simultaneous determination of RDX and TNT in synthetic and real mixtures. Deconvolution of current contributions of mixtures at peak potentials of constituents was performed by multiple linear regression. The proposed method was successfully applied to the analysis of military explosives comp A5 and octol, and method validation was performed both against HPLC on a comp B (TNT+RDX) sample and against GC-MS on real post-blast residual samples containing both explosives. PMID:24054661

Üzer, Ay?em; Sa?lam, Sener; Tekdemir, Yasemin; Ustamehmeto?lu, Belk?s; Sezer, Esma; Erça?, Erol; Apak, Re?at

2013-10-15

161

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

NASA Astrophysics Data System (ADS)

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.

Reyff, James A.; Donavan, Paul

2005-09-01

162

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

SciTech Connect

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.

Wells, S.G. [Univ. of California, Riverside, CA (United States)] [Univ. of California, Riverside, CA (United States); McFadden, L.D. [Univ. of New Mexico, Albuquerque, NM (United States)] [Univ. of New Mexico, Albuquerque, NM (United States); Poths, J.; Olinger, C.T. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)

1995-07-01

163

Superplasticized concretes for rehabilitation of bridge decks and highway pavements  

NASA Astrophysics Data System (ADS)

Two mixes, one with medium workability and high cement content suitable for bridge deck replacement and another with high workability suitable for structural and pavement concrete were selected for intensive study. For these mixes, properties of the fresh concrete (slump, vebe time, flow table spread, air content, initial and final setting times) are reported. The effects of retempering are described. The influence of three types of cements on the properties of plastic and hardened concrete is explained. Complete results of the following tests are presented: compressive strength, tensile strength, flexural strength, static modulus of elasticity, dynamic modulus of elasticity, pulse velocity and dry unit weight at 1, 3, 28 and 90 days curing. The selected concretes had high durability and satisfactory resistance against deicer scaling.

Ramakrishnan, V.; Coyle, W. V.

1981-01-01

164

Development on preventive maintenance management system for expressway asphalt pavements  

Microsoft Academic Search

In view of the status that there was no expressway pavement preventive maintenance management system at home and abroad at present, based on the technology theory obtained by the author and the demands and process of expressway asphalt pavement preventive maintenance management, preventive maintenance management system for expressway asphalt pavement (EPMMS (V1.0)) was developed. The work or functions of expressway

Hu Guoxiang; Li Jie

2010-01-01

165

Friction evaluation of concrete paver blocks for airport pavement applications  

NASA Technical Reports Server (NTRS)

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.

Yager, Thomas J.

1992-01-01

166

Evaluation of Performance and Design of Ultra-Thin Whitetopping (Bonded Concrete Resurfacing) Using Large-Scale Accelerated Pavement Testing  

Microsoft Academic Search

Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC

Scott Newbolds; Jan Olek

2008-01-01

167

Evaluation of performance and design of Ultra-Thin Whitetopping (bonded concrete resurfacing) using large-scale accelerated pavement testing  

Microsoft Academic Search

Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC

Scott Andrew Newbolds

2007-01-01

168

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...

169

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

PubMed Central

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

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

2010-01-01

170

Pavement management using hyperspectral imagery  

NASA Astrophysics Data System (ADS)

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.

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

2003-08-01

171

Impact of compressed natural gas fueled buses on street pavements  

SciTech Connect

Capital Metro, the Ausin, Texas transit authority, is currently evaluating a number of CNG fueled buses. As part of the U.S. DOT Region Six University Transportation Centers Program (UTCP), a study was instigated into the scale of incremental pavement consumption associated with the operation of these buses. The study suggests that replacing current vehicles with CNG powered models utilizing aluminum storage tanks would raise average network equivalent single rehabilitation costs across the network of over four percent. Finally, it recommends that full cost study be undertaken with evaluation of the adoption of alternative bus fuels - which includes pavement and environmental impacts.

Yang, D.; Harrison, R.

1995-07-01

172

Analysis, testing and verification of the behavior of composite pavements under Florida conditions using a heavy vehicle simulator  

NASA Astrophysics Data System (ADS)

Whitetopping (WT) is a rehabilitation method to resurface deteriorated asphalt pavements. While some of these composite pavements have performed very well carrying heavy load, other have shown poor performance with early cracking. With the objective of analyzing the applicability of WT pavements under Florida conditions, a total of nine full-scale WT test sections were constructed and tested using a Heavy Vehicle Simulator (HVS) in the APT facility at the FDOT Material Research Park. The test sections were instrumented to monitor both strain and temperature. A 3-D finite element model was developed to analyze the WT test sections. The model was calibrated and verified using measured FWD deflections and HVS load-induced strains from the test sections. The model was then used to evaluate the potential performance of these test sections under critical temperature-load condition in Florida. Six of the WT pavement test sections had a bonded concrete-asphalt interface by milling, cleaning and spraying with water the asphalt surface. This method produced excellent bonding at the interface, with shear strength of 195 to 220 psi. Three of the test sections were intended to have an unbonded concrete-asphalt interface by applying a debonding agent in the asphalt surface. However, shear strengths between 119 and 135 psi and a careful analysis of the strain and the temperature data indicated a partial bond condition. The computer model was able to satisfactorily model the behavior of the composite pavement by mainly considering material properties from standard laboratory tests and calibrating the spring elements used to model the interface. Reasonable matches between the measured and the calculated strains were achieved when a temperature-dependent AC elastic modulus was included in the analytical model. The expected numbers of repetitions of the 24-kip single axle loads at critical thermal condition were computed for the nine test sections based on maximum tensile stresses and fatigue theory. The results showed that 4" slabs can be used for heavy loads only for low-volume traffic. To withstand the critical load without fear of fatigue failure, 6" slabs and 8" slabs would be needed for joint spacings of 4' and 6', respectively.

Tapia Gutierrez, Patricio Enrique

173

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

USGS Publications Warehouse

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.

Ryden, N.; Park, C.B.

2006-01-01

174

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

SciTech Connect

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.

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

1997-07-03

175

The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment  

Microsoft Academic Search

Abstract: Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption,has been hindered,by a lack of detailed knowledge,of their hydrological performance. This paper describes a research programme,that produced,detailed information,on the hydrological behaviour of a car park surface. The study involved the construction,of full-scale permeable,pavement,model,car park structures and a rainfall simulator for

C. T. Andersen; I. D. L. Foster; C. J. Pratt

1999-01-01

176

Improvement of etch selectivity and process latitude in ArF lithography by spin coating type hard masking material  

NASA Astrophysics Data System (ADS)

The role of photoresist masking is greatly increased for 193 nm (ArF) lithography, which was no problem for 248 nm (KrF) DUV lithography. Main reason for this masking is poor etch resistance for currently developed ArF resist. The methacrylate (MA) back-bone type used for 193 nm resist shows poor etch resistance compared to the poly-hydroxy-stylene (PHS) back-bone type used for 248 nm resist. Acrylate type back-bone has high transmittance, so that better contrast and resolution can be obtained, although the etch resistance and the mechanical hardness is dropped. The radical polymerization method is mainly used for methacrylate resin synthesis, which is different from the anionic polymerization or blending system for 248 nm resist. In case of radical polymerization, the resultant resin has bad uniformity (or homogeneity) across the resist and has wide degree of poly-dispersion (1.8~2.0) which is about 2 times larger than that of 248 nm resist. This nonuniformity and wide dispersion makes notable line edge roughness for 193 nm resist compared to 248 nm resist. It is necessary to use organic (such as amorphous carbon) and/or inorganic (PE-SiON) masking layer due to weak etch resistance of 193 nm resist. So we need another spin coating material that can function as a mask and the anti-reflection film. Also we need to control this masking layer due to the alignment failure by absorption characteristics of high carbon density, the reduction of the throughput, the additional CVD equipment cost, and the increased particle during the additional layer deposition process. Thus we developed spin type dual hard masking material, including silicon contained materials. We tried to maximize the carbon density of base resin and to control many additive materials (cross-linker or catalyst) in order to optimize the optical factor such as the refractive index and the absorption coefficient. Also we could improve the surface roughness and could control the hydrogen characteristics for wider process margin with maximize etch selectivity between the resist and sub-layer. And we controlled silicon content portion and acidity, optical performance through the change of chromorphore's ratio or specious for the lithography performance. We could obtain good etch selectivity and process latitude, and reduce the cost for the mass production of sub-70 nm devices by using the suggested masking material.

Lee, Chang Ho; Lee, Jung Hoon; Park, Kyoung Sil; Han, Seok; Kim, Do-hyeon; Kang, KyongRim; Kim, Youngho; Kim, Tae Sung; Kang, Hye-Young; Oh, Hye-Keun

2006-03-01

177

Reducing greenhouse gas emissions through strategic management of highway pavement roughness  

NASA Astrophysics Data System (ADS)

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.

Wang, Ting; Harvey, John; Kendall, Alissa

2014-03-01

178

Influence of concrete flexural strength on airport pavement thickness  

Microsoft Academic Search

Federal aviation administration rigid and flexible iterative elastic layered design (FAARFIELD) software program became the exclusive approved method for airport pavement thickness design adopted by federal aviation administration (FAA) in the United States after the advisory circular AC150\\/5320-6E \\

Tammam Merhej; Decheng Feng

2011-01-01

179

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...

180

Probabilistic Numerical Simulation of Pavement Performance using MEPDG  

Microsoft Academic Search

It is widely acknowledged that the accurate simulation of complex engineering systems, such as nuclear power reactors, modern weapon systems, and aircraft, requires probabilistic analysis due to inherent uncertainties in their models' parameters. The demand for and the complexity of probabilistic analysis prompted Sandia National Laboratories to develop a versatile software toolkit, DAKOTA, adaptable to various engineering applications. Pavements are

Steven F. Wojtkiewicz; Lev Khazanovich; Gaurav Gaurav; Raul Velasquez

2010-01-01

181

A study of tire/pavement interaction noise using near- field acoustical holography  

NASA Astrophysics Data System (ADS)

In this thesis, Nearfield Acoustical Holography (NAH) is applied as a tool to study the mechanisms of tire/pavement interaction noise-a major contributor to highway noise. NAH is a technique that reconstructs the three-dimensional acoustic field from a two- dimensional measurement of the complex pressure. Since NAH measurements are conducted in the acoustic nearfield, areas of maximum radiation from the tire may be localized with a much finer resolution than with conventional measurements. Not only can acoustic pressure be reconstructed, but also sound intensity vectors and sound power. To extend NAH from controlled, laboratory experiments to harsh realistic conditions of a rolling tire, NAH is modified to incorporate the effects of a moving medium and multiple partially coherent sources. Tire/pavement interaction noise is composed of several sources, e.g. interactions of the leading and trailing edges of the tire with the pavement, and sidewall vibration. Therefore, NAH is modified to improve separation of acoustic fields associated with multiple partially coherent sources. These techniques are used to visualize the acoustic field of a rolling tire on real pavements. A scanning mechanism is attached to an automobile trailer for measurements of tire noise under realistic conditions. Several types of tires are evaluated, including a blank tire, a tire with equally spaced transverse grooves, a tire with only circumferential grooves, and two commercial passenger car tire. The tires are tested on both smooth and rough pavements, and at two speeds (56 km/hr and 80 km/hr). Wavenumber spectra of the tire and pavement surfaces are computed when possible to quantify the roughness levels. Although the measurements were made along a plane 10 cm from the tire sidewall, sound pressure and intensity are reconstructed along a plane touching the surface of the tire to localize noise source. In addition to the side plane, front and rear planes were evaluated for two configurations to enhance the study of leading and trailing edge noise generation. Finally, sound power for each configuration was calculated to evaluate global trends. These results provide further insight into the sources and mechanisms of tire/pavement interaction noise.

Ruhala, Richard James

1999-12-01

182

SHADOW PRICES AND DISTANCE FUNCTIONS: AN ANALYSIS FOR FIRMS OF THE SPANISH CERAMIC PAVEMENTS INDUSTRY  

Microsoft Academic Search

This paper deals with the calculation of shadow prices for two industrial wastes generated on their production processes by a sample of eighteen firms belonging to the Spanish ceramic pavements industry. These prices are used to construct a corrected index of productivity which allows for considering wastes going with the production of marketable goods. It is followed the ethodologicalapproach first

Francesc Hernández Sancho; Andrés Picazo; Ernest Reig Martínez

1999-01-01

183

Research on the characteristics of temperature field of asphalt pavement in seasonal frozen region  

NASA Astrophysics Data System (ADS)

The characteristics of climate in seasonal frozen area are low temperature and a large range of temperature variation between day and night in winter. These characteristics often lead to problems of asphalt pavement, especially transverse cracks. To reduce the problems of asphalt pavement, it is necessary to examine the distribution of the temperature range of asphalt pavement. A three-dimensional finite element model was used, taking the SMA asphalt pavement as an example with solid70 and plane55 unit features of ANSYS software. It can obtain the relationship between temperature gradient and time and the relationship between temperature gradient and depth. In addition, a function relation model of stress and time was also established. It can provide a theoretical basis for the prevention and treatment of problems of asphalt pavement in seasonal frozen area. Moreover, it has an important significance for improving asphalt pavement design.

Qiao, Jiangang; Liu, Weizheng

2014-08-01

184

FILTERING OF ARTIFACTS AND PAVEMENT SEGMENTATION FROM MOBILE Jorge Hernandez and Beatriz Marcotegui  

E-print Network

FILTERING OF ARTIFACTS AND PAVEMENT SEGMENTATION FROM MOBILE LIDAR DATA Jorge Hern/2 KEY WORDS: LIDAR, point cloud, filtering ground data, segmentation ground data, mathematical acquired from mobile LIDAR systems. Our approach exploits 3D information by using range images and several

Cord, Aurélien

185

Improvements to a Transport Model of Asphalt Binder Oxidation in Pavements: Pavement Temperature Modeling, Oxygen Diffusivity in Asphalt Binders and Mastics, and Pavement Air Void Characterization  

E-print Network

in asphalt binders and mastics, and characterizing air voids in pavements, these key model elements were studied in turn. Hourly pavement temperatures were calculated with an improved one-dimensional heat transfer model, coupled with methods to obtain model...

Han, Rongbin

2012-07-16

186

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

NASA Astrophysics Data System (ADS)

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 appropriate lithologies and cosmogenic isotopes for obtaining an accurate chronology of desert pavements. Moreover, 3He dating of six in situ samples from basalt flows with independent 39Ar/40Ar ages will begin to address long-term time-averaged wind erosion rates of bedrock while enabling wind-erosion rate corrections for pavement ventifacts. Our results and methodology can be applied worldwide and will aid future research in the many environments where ventifacts and/or high wind erosion rates are found.

Dortch, J.; Schoenbohm, L. M.

2011-12-01

187

Characteristics of Vertical Type Organic Transistor Using N-Type Material and its Application for OLED  

Microsoft Academic Search

We have fabricated static induction organic transistor of vertical type in order to improve the problems of conventional organic thin film transistor (OTFT). The vertical type organic transistors were fabricated by using n-type organic semiconductor materials such as F16CuPc, NTCDA and PTCDI C-8. The effects of carrier mobility of organic active materials, the thickness of thin film and gate structure

Se Young Oh; Ji-Young Lee

2006-01-01

188

Cutting of Solid Type Molded Composite Materials by Q-switched Fiber Laser with High-Performance Nozzle  

NASA Astrophysics Data System (ADS)

This paper deals with the effects of the nozzle shape on cutting results and fundamental characteristics of laser cutting of solid type molded composite materials, which was composed of semiconductor board and epoxy-resin molding compounds, by Q-switched single-mode fiber laser. Experimental results clarified that high speed cutting of 16 mm/s could be carried out using a Laval throat nozzle with initial expansion zone, which also led to straighter kerf shape and narrower kerf width than other nozzles. Besides, Laval throat nozzle made it possible to reduce the kerf width, and the difference of kerf width between irradiation-side and exit-side became smaller. Nitrogen assist gas led to the narrow kerf width and straight kerf shape. Furthermore, the difference of kerf between substrate side and epoxy-resin side became smaller. Substrate side irradiation was more suitable for precision cutting than epoxy-resin side irradiation. These results proved that Q-switched single-mode fiber laser was useful for cutting of composite materials.

Okamoto, Yasuhiro; Kitada, Ryoji; Uno, Yoshiyuki; Doi, Hiroyuki

189

Wearability of Portland Cement Concrete Pavement Finishes  

E-print Network

fine aggregate types: a siliceous sand (SF), also referred to as Colorado sand, obtained near Eagle Lake, Texas, and a lightweight fine aggregate (LF) from a burned clay manufactured in a rotary kiln in Texas. The physical properties of the fine...WEARABILITY OF' PORTEAND CEMENT CONCRETE PAPFMENT FINISHES A Thesis by William Rem McKeen Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1971...

McKeen, William Rew

1971-01-01

190

Evaluation of western and eastern shale oil residua as asphalt pavement recycling agents  

SciTech Connect

The objective of this investigation was to perform a preliminary evaluation of the utility of residual materials prepared from Green River Formation (western) and New Albany Shale (eastern) shale oils as recycling agents for aged asphalt pavement. Four petroleum asphalts were first aged by a thin-film accelerated-aging test, which simulates long service life of asphalt in pavement. The aged asphalts were mixed (recycled) with Green River Formation shale oil distillation residua to restore the original viscosities. Separately, for comparison, a commercial recycling agent was used to recycle the aged asphalts under the same circumstances. The recycled asphalts were reaged and the properties of both binder and asphalt-aggregate mixtures studied. Originally, the same study was intended for an eastern shale residua. However, the eastern shale oil distillation residua with the required flash point specification also had the properties of a viscosity builder; therefore, it was studied as such with asphalts that do not achieve sufficient viscosity during processing to serve as usable binders. Results show that Green River Formation shale oil residuum can be used to restore the original asphalt properties with favorable rheological properties, the shale oil residuum has a beneficial effect on resistance to moisture damage, the low-temperature properties of the shale oil residuum recycled asphalts are not adversely affected, and the low-temperature properties of the shale oil residuum recycled asphalts are dependent upon the chemistry of the mixture. The eastern shale oil residua was blended with soft petroleum asphalts. Results show the products have higher viscosities than the starting materials, the rheological properties of the soft asphalt-eastern shale oil residue blends are acceptable, and the eastern shale oil residue has dispersant properties despite its high viscosity. 11 refs., 3 figs., 9 tabs.

Harnsberger, P.M.; Robertson, R.E.

1990-03-01

191

POROUS PAVEMENT: RESEARCH; DEVELOPMENT; AND DEMONSTRATION  

EPA Science Inventory

This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available stormwater management techniq...

192

Full scale demonstration of air-purifying pavement.  

PubMed

Experiments concerning a full-scale demonstration of air purifying pavement in Hengelo, The Netherlands, are reported. The full width of the street was provided with concrete pavement containing TiO? over a length of 150 m ("DeNOx street"). Another part of the street, about 100 m, was paved with normal paving blocks ("Control street"). The outdoor monitoring was done during 26 days for a period exceeding one year, and measured parameters included traffic intensity, NO, NO? and ozone concentrations, temperature, relative humidity, wind speed and direction, and the visible and UV light irradiance. Prior and parallel to these field measurements, the used blocks were also measured in the lab to assess their performance. The NOx concentration was, on average, 19% (considering the whole day) and 28% (considering only afternoons) lower than the obtained values in the Control street. Under ideal weather conditions (high radiation and low relative humidity) a NOx concentration decrease of 45% could be observed. PMID:23731840

Ballari, M M; Brouwers, H J H

2013-06-15

193

Effects of Various Deicing Chemicals on Pavement Concrete Deterioration  

Microsoft Academic Search

The deleterious effects of deicers on concrete pavements and bridges have concerned concrete researchers for several decades. The present study experimentally investigates the effects of different deicers on concrete deterioration. Laboratory simulations of environmental conditions (wet\\/dry and freeze\\/thaw cycling) were conducted on highway concrete samples with various deicer chemicals (NaCl, CaCl 2, MgCl2, calcium magnesium acetate (CMA) of 5 different

HYOMIN LEE; ROBERT D. CODY; ANITA M. CODY; PAUL G. SPRY

194

Abrasion resistance of concrete containing nano-particles for pavement  

Microsoft Academic Search

The abrasion resistance of concrete containing nano-particles for pavement is experimentally studied. Both nano-TiO2 and nano-SiO2 are, respectively, employed to be as the additives. For comparison, the abrasion resistance of plain concrete and the concrete containing polypropylene (PP) fibers is also experimentally studied in this work. The test results indicate that the abrasion resistance of concretes containing nano-particles and PP

Hui Li; Mao-hua Zhang; Jin-ping Ou

2006-01-01

195

Mechanistic modeling of roughness on continuously reinforced concrete pavement  

E-print Network

ABSTRACT Mechanistic Modeling of Roughness on Continuously Reinforced Concrete Pavements. (December 1996) Supriya Sriraman, B. S. , Osmania University, India Chair of Advisory Committee: Dr. Dan G. Zollinger Roughness can be termed as the irregularity... conunittee, Dr. Dan Zollinger, for the support and guidance he extended to me. During the two years I worked with him, he has always been there to advice me on my research and help me with problems that I could not tackle myself. I am immensely thankful...

Sriraman, Supriya

1996-01-01

196

Layer equivalency factors and deformation characteristics of flexible pavements  

E-print Network

Russian Equation THE TEST PROGRAM The Test Site and The Soils Pavement Pressuremeter Test The Dynaflect Test Penetration Test as a Reference The Texas Triaxial Test ANALYSIS OF THE RESULTS The Pressuremeter Tests The Texas Triaxial Test Modulus... Dynaflect Modulus Correlations and Analysis The Equivalency Factors Page 12 16 23 31 31 31 48 48 51 52 52 67 74 86 TABLE OF CONTENTS (Continued) New Standard Procedure for Cyclic Pressuremeter Test PROCEDURE FOR DETERMINING...

Hung, Jung-Tsann

1981-01-01

197

Hybrid green permeable pave with hexagonal modular pavement systems  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

198

Design Methodologies of Asphalt Pavement Used in China and Mozambique  

NASA Astrophysics Data System (ADS)

This study discusses and compares Asphalt Concrete (AC) pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC) methodologies). The SATCC design methodologies use California Bearing Ratio (CBR) and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the South African design methods give nearly the same thickness; this study concludes that these methods can be used in both countries; China and Mozambique. The results also show that the strong point of Chinese method is verifying the tensile stress and allowable displacement on the pavement calculated from computer program APDS.

Francisco Rufino Diogo, Jose; Shubber, Ammar Abbas Mohammed; Lin, Mu Han

199

Exploration of Pavement Oxidation Model Applications and Field Validation  

E-print Network

oxidation have been investigated, such as oxidation kinetics, asphalt hardening in response to oxidation, pavement design, and environmental conditions. Based on understandings on those elements, pavement oxidation models have been developed to predict...

Cui, Yuanchen

2014-08-11

200

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

NASA Astrophysics Data System (ADS)

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.

Dietze, Michael; Fuchs, Markus; Kleber, Arno

2014-05-01

201

Microleakage between different types of base materials.  

PubMed

This study investigated the sealing properties of various combinations of base materials. Three chemically cured and three light-activated base materials were combinationally used to make 15 sample groups. The samples were thermocycled and immersed in 0.05% crystal violet solution for 1 hour. They were then embedded in clear casting resin, sectioned, and photographed. The interfaces of the samples were digitized. The ratio of the total interface length to the penetration of leakage was calculated and compared. The results indicated that the combination of Cavalite and VLC Dycal materials had the least microleakage and was significantly different from the other 14 groups. PMID:1311379

Suliman, A A; Chan, K C

1992-02-01

202

Contributions to an Improved Oxygen and Thermal Transport Model and Development of Fatigue Analysis Software for Asphalt Pavements  

E-print Network

Fatigue cracking is one primary distress in asphalt pavements, dominant especially in later years of service. Prediction of mixture fatigue resistance is critical for various applications, e.g., pavement design and preventative maintenance. The goal...

Jin, Xin

2012-02-14

203

On-site inspections of pavement damages evolution using GPR  

NASA Astrophysics Data System (ADS)

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 approximately 160 km/day at 40 km/h speed, on the average. After processing and first-checking, GPR profiles were divided into homogeneous sections according to the combination of different parameters (e.g. route analyzed, long distance conditions of regularity/irregularity in layers arrangement). In such context, a high consistency between surface damages, mismatches from the GPR scans, and boundary environmental conditions was demonstrated. In addition, deep mismatches were detected even for early-stage or unrevealed faults. The second set of surveys was carried out in autumn in high humidity conditions, due to recent rainfalls. 160 km of relevant routes from the same road network were investigated. Results showed a high consistency with those collected during the first-stage of surveys. Minor changes were found in those sections with low traffic loads (e.g. farther away from the biggest town of Rieti), whereas major mismatches were detected in wetlands (e.g. close to rivers), work zones, and nearby those sections already deeply damaged in the past. This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar'.

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

2014-05-01

204

Analysis, testing and verification of the behavior of composite pavements under Florida conditions using a heavy vehicle simulator  

Microsoft Academic Search

Whitetopping (WT) is a rehabilitation method to resurface deteriorated asphalt pavements. While some of these composite pavements have performed very well carrying heavy load, other have shown poor performance with early cracking. With the objective of analyzing the applicability of WT pavements under Florida conditions, a total of nine full-scale WT test sections were constructed and tested using a Heavy

Patricio Enrique Tapia Gutierrez

2007-01-01

205

Development of a Pavement Maintenance and Rehabilitation Project Formation and Prioritization Methodology that Reflects Agency Priorities and Improves Network Condition  

E-print Network

budgetary constraint. Future pavement condition was projected using performance prediction models and the process is repeated throughout the planning horizon to produce a multi-year pavement management plan. Data from Bryan district, which consists of 7,075...

Narciso, Paul John Ross

2013-07-22

206

Sensitivity analysis of flexible pavement response and AASHTO 2002 design guide for properties of unbound layers  

E-print Network

in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2004 Major Subject: Civil Engineering SENSITIVITY ANALYSIS OF FLEXIBLE PAVEMENT RESPONSE AND AASHTO 2002 DESIGN GUIDE FOR PROPERTIES... (Member) (Head of Department) May 2004 Major Subject: Civil Engineering iii ABSTRACT Sensitivity Analysis of Flexible Pavement Response and AASHTO 2002 Design Guide for Properties...

Masad, Sanaa Ahmad

2004-09-30

207

ANALYSIS OF PERFORMANCE OF THE ULTRA-THIN WHITETOPPING SUBJECTED TO SLOW MOVING LOADS IN AN ACCELERATED PAVEMENT TESTING FACILITY  

Microsoft Academic Search

Ultra-Thin Whitetopping (UTW) is rapidly emerging as a technology that can be used for the rehabilitation of deteriorated pavements. To investigate the performance of UTW when they are placed over flexible pavements and subjected to a slow moving load, four whitetopping mixtures were placed over a milled asphalt surface in the Accelerated Pavement Testing (APT) facility of the Indiana Department

Sudarshan Rajan; Jan Olek; Thomas L. Robertson; Tommy Nantung; W. Jason Weiss

208

EVALUATION OF THE INFLUENCE OF TACK COAT CONSTRUCTION FACTORS ON THE BOND STRENGTH BETWEEN PAVEMENT LAYERS  

E-print Network

Administration. 16. ABSTRACT This study investigated the influence of several factors on the adhesive bondEVALUATION OF THE INFLUENCE OF TACK COAT CONSTRUCTION FACTORS ON THE BOND STRENGTH BETWEEN PAVEMENT Evaluation of the Influence of Tack Coat Construction Factors on the Bond Strength between Pavement Layers 7

209

Nondestructive testing of asphalt pavements for structural condition evaluation: a state of the art  

Microsoft Academic Search

Nondestructive testing provides ideal means to test pavement structure in a rapid and convenient manner. In last few years, significant development has taken place in this field. This paper, presents some of the major conventional as well as emerging nondestructive evaluation methods for in situ structural assessment of asphalt pavements. Discussion of methods is primarily directed towards the estimation of

Amit Goel; Animesh Das

2008-01-01

210

A new technology of preventive reinforcement for the semi-rigid base of asphalt pavement expressway  

Microsoft Academic Search

As for the existing treated methods for the base layer of asphalt pavement, there were at least two main shortages: the one was the lagged technology, the other one was the unseasonable choosing of treated time. In order to develop a new preventive maintenance technologies for the asphalt pavement, in this paper, the authors propose that, before the damages happen

Guo-xiang Hu; Jie Li; Bai-lin Sun

2011-01-01

211

New structural systems for zero-maintenance pavements. Volume 3: Anchored pavement system designed for Edens Expressway  

Microsoft Academic Search

The response of the Edens Expressway subjected to mechanical and environmental loads using the anchored pavement concept is discussed. The mechanical and thermal properties of materials that could be encountered in future reconstruction of Edens Expressway are presented in a consistent form for computer programming. These properties are viewed as typical design values during investigation of pavement response. The behavior

S. K. Saxena; S. G. Militsopoulos

1980-01-01

212

The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment  

NASA Astrophysics Data System (ADS)

Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption has been hindered by a lack of detailed knowledge of their hydrological performance. This paper describes a research programme that produced detailed information on the hydrological behaviour of a car park surface. The study involved the construction of full-scale permeable pavement model car park structures and a rainfall simulator for use in the laboratory. A monitoring procedure was developed in order to measure inputs and changes in drainage, storage and evaporation over short and long time-scales (2 hours to 3 months). A range of simulated rainfalls, which varied in intensity and duration, was applied to the model car park surfaces. Hydrological processes were monitored over an 18-month period. Results demonstrated that evaporation, drainage and retention in the structures were strongly influenced by the particle size distribution of the bedding material and by water retention in the surface blocks. In general, an average of 55% of a one-hour duration, 15 mm h-1 rainfall event could be retained by an initially air-dry structure. Subsequent simulations demonstrated that 30% of a one-hour duration, 15 mm h-1 rainfall event could be stored by an initially wet structure (with a minimum time interval between rainfall applications of 72 hours).

Andersen, C. T.; Foster, I. D. L.; Pratt, C. J.

1999-03-01

213

Field study of effects of construction procedures on concrete pavement surfaces  

E-print Network

Strength. 2. 4. 5 Shear Strength . 2. 4. 6 Nondestructive Strength Determinatious 2. 5 Statistical Analysis of Strength. 2. 5. 1 General. 2. 5. 2 Variations in Strength 2. 5. 3 Properties of Concrete 2. 6 Statistical Analysis of Data. III...PIELD STUDY OF EPPECTS OP CONSTRUCTION PROCEDURES ON CONCRETE PAVEMENT SURFACES A Thesis by JEFFREY LELAND DAVIS Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OP...

Davis, Jeffrey Leland

1973-01-01

214

HEAVY METAL RETENTION WITHIN A POROUS PAVEMENT STRUCTURE  

Microsoft Academic Search

Porous pavements with reservoir structure for infiltration of runoff from parking spaces and residential streets offer the opportunity to dispose water without using additional space in urban areas. However, pollutants in urban runoff endanger soils and groundwater, when pol- lutant retention in the structure is not sufficient. Porous pavement structures with four differ- ent subbase materials were tested in rigs.

C. Dierkes; A. Holte; W. F. Geiger

215

Dynamical Processes on Desert Pavements and the Healing of Surficial Disturbances  

E-print Network

of a layer of accumulating aeolian sediment. The results presented here support a recent model of pavement formation on volcanic flow surfaces that emphasizes the importance of dust-accretion over deflation in pavement genesis (Wells et al., 1985; Mc- Fadden et al., 1987). SETTING AND EXPERIMENTAL APPROACH

Ahmad, Sajjad

216

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

SciTech Connect

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.

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

2011-02-05

217

Using ground-penetrating radar for assessing the structural needs of asphalt pavements  

Microsoft Academic Search

Ground-penetrating radar (GPR) is a nondestructive testing (NDT) approach for pavement investigation that has been developed and improved upon over the past 30 years. This paper aimed to document how the GPR technique could be incorporated successfully into the process of assessing the structural needs of asphalt pavements. Background information is provided regarding the usage of GPR for the evaluation

C. Plati; A. Loizos

2012-01-01

218

Discussion on the Prediction Method of the Pavement Performance for Expressway  

Microsoft Academic Search

The empirical regression model was selected for forecasting the preventive maintenance time; the grey system theory was used to determine if pavements were fit for preventive maintenance. Combined with the instance, on the forecasting of the pavement performance for an expressway, the application of the grey system theory was introduced.

He Xiao-ming; Guan Peng; Hu Guo-xiang; Zhou Lin

2009-01-01

219

Evaluation of the durability of titanium dioxide photocatalyst coating for concrete pavement  

Microsoft Academic Search

The use of titanium dioxide (TiO2) ultrafine particles as coating for concrete pavement have received considerable attention in recent years as these particles can trap and decompose organic and inorganic air pollutants by a photocatalytic process. In spite of these promising benefits, the durability and resistance to wear of TiO2 surface coating has not been evaluated. The objective of this

Marwa M. Hassan; Heather Dylla; Louay N. Mohammad; Tyson Rupnow

2010-01-01

220

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

PubMed Central

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

Jinping, Li; Xiaojuan, Quan

2013-01-01

221

Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.  

PubMed

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

Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

2013-01-01

222

Enantiomeric separation and quantification of ephedrine-type alkaloids in herbal materials by comprehensive two-dimensional gas chromatography  

Microsoft Academic Search

The separation of ephedrine-type alkaloids and their enantiomers in raw herbs and commercial herbal products was investigated by carrying out enantioselective separation in the first-dimension column (containing ?-cyclodextrin as the chiral selector) of a comprehensive two-dimensional gas chromatography (GC×GC) system, whereas a polar polyethylene glycol capillary column was used for separation in the second dimension. Naturally occurring ephedrine-type alkaloids and

Min Wang; Philip J. Marriott; Wing-Hong Chan; Albert W. M. Lee; Carmen W. Huie

2006-01-01

223

Smart Road Pavement Research HomePage  

NSDL National Science Digital Library

Dubbed "the Smart Road" by Virginia's Department of Transportation, this full-scale facility for pavement research and evaluation of high-tech transportation systems uses computers, electronics, and satellites to create a realistic environment for collecting traffic and environmental data under controlled conditions, "and should advance the general understanding of the engineering behavior of pavement systems." This site, from the Virginia Tech Civil Engineering Materials Program, provides information from the researchers who have designed the Smart Road. The page contains a description of the project's current status, an explanation of objectives, construction photos, a detailed description of the instrumentation used, and data. Note, the research plan and testing links are still under construction. This site introduces an interesting project for highway and transportation engineers.

224

Recycling of plastic and rubber tire waste in asphalt pavements  

SciTech Connect

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.

Morrison, G.R.; Lee, N.K.; Hesp, S.A.M. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Chemistry

1994-12-31

225

Pavement Design TTP Orientation Seminar  

E-print Network

the "good old" days? #12;Traffic Variables Highways - it's the trucks · Loads · Tire pressures · Speeds? ­ are your loads controlled? #12;Big Truck - 1960 #12;Big Truck - 2001 #12;Super Single Tires #12;Australian of these materials can be perpetually recyclable into the same infrastructure #12;#12;#12;#12;Pavements

Handy, Susan L.

226

Pavement Design TTP Orientation Seminar  

E-print Network

Variables Highways - it's the trucks · Loads · Tire pressures · Speeds · Dynamics (interaction controlled? #12;Big Truck - 1960 #12;Big Truck - 2001 #12;Super Single Tires #12;Australian for "truck" "Road of these materials can be perpetually recyclable into the same infrastructure #12;#12;#12;#12;Pavements

Handy, Susan L.

227

A mechanistic model for the prediction of stresses, strains, and displacements in continuously reinforced concrete pavements  

E-print Network

Approved as to style and content by: Mikael P. J. Olsen (Chairman of Committee) Ro' rt L. Lytton (Member) I Kirk YV. Brown (Member) Donald A. Ma well (Head of Department) May 1988 ABS TACT A Mechanistic Model for the Prediction of Stresses..., Strains, and Displacements in Continuously Reinforced Concrete Pavements. (May 1988) Richard Paul Palmer, B. S. , Cornell University Chairman of Advisory Committee: Dr. Mikael P. J. Olsen Rational, computer-based models that can predict the behavior...

Palmer, Richard Paul

1988-01-01

228

Simultaneous etching of polysilicon materials with different doping types by low-damage transformer-coupled plasma technique  

Microsoft Academic Search

The feasibility of simultaneously etching n+, p+, and undoped polysilicon (poly-Si) materials by a commercial transformer coupled plasma (TCP) reactor has been investigated in this study. Response surface methodology (RSM) was used to optimize process parameters including pressure, TCP source power, bias power, and Cl2\\/HBr flow on the main etch step. Quantitative relationships between etching performance and process parameters were

Chi-Chao Hung; Horng-Chih Lin; Meng-Fan Wang; Tiao-Yuan Huang; Han-Chang Shih

2002-01-01

229

Pavement performance prediction using adaptive logic networks  

Microsoft Academic Search

Pavement performance is one of the most important components of the pavement management system. Prediction of the future performance of a pavement section is important in programming maintenance and rehabilitation needs. Models for predicting pavement performance have been developed on the basis of traffic and age. The purpose of this research is to extend the use of a relatively new

Mohd Y Nawaiseh

2002-01-01

230

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

PubMed

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

Scholz, Miklas; Uzomah, Vincent C

2013-08-01

231

Precast concrete pavements  

NASA Astrophysics Data System (ADS)

This report reviewed published literature on precast concrete pavements and found that precast concrete pavements have had some limited application in airfields, roads, and storage areas. This review of past experience and an analytical study of precast slabs concluded that existing design and construction techniques can be adapted for use with precast concrete pavements, but more work is needed to develop effective and easily constructed load transfer designs for slab joints. Precast concrete does not offer any advantage for conventional pavements due to its high cost and surface roughness, but it may find applications for special problems such as construction in adverse weather, subgrade settlement, temporary pavements that need to be relocated, and military operations.

Rollings, R. S.; Chou, Y. T.

1981-11-01

232

Recent advances in the characterization of transportation geo-materials. Geotechnical special publication No. 89  

SciTech Connect

This special publication, sponsored by the Pavements Committee of the Geo-Institute, contains five papers from sessions of the Third National Conference of the Geo-Institute. The goal of the project was to encourage the application of geotechnical fundamentals in pavement design, and help the transfer of new developments in dealing with other earth-supported structures subjected to static, dynamic, and cyclic loads. Papers focus on recent advances in field and laboratory characterization of transportation geo-materials, including the use of various nondestructive testing techniques (falling weight deflecometer, spectral analysis of surface waves, ground penetrating radar, seismic pavement analyzer, Humbold stiffness gauge) and cone penetration testing for field characterization, application of a new Tube Suction test method for characterizing durability of pavement foundation core samples, and laboratory stress path testing of granular materials under dynamic confinement conditions using a new advanced triaxial test device.

Tutumluer, E.; Papagiannakis, A.T. [eds.

1999-07-01

233

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

NASA Astrophysics Data System (ADS)

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.

Quade, Jay

2001-09-01

234

Multimodal approach to seismic pavement testing  

USGS Publications Warehouse

A multimodal approach to nondestructive seismic pavement testing is described. The presented approach is based on multichannel analysis of all types of seismic waves propagating along the surface of the pavement. The multichannel data acquisition method is replaced by multichannel simulation with one receiver. This method uses only one accelerometer-receiver and a light hammer-source, to generate a synthetic receiver array. This data acquisition technique is made possible through careful triggering of the source and results in such simplification of the technique that it is made generally available. Multiple dispersion curves are automatically and objectively extracted using the multichannel analysis of surface waves processing scheme, which is described. Resulting dispersion curves in the high frequency range match with theoretical Lamb waves in a free plate. At lower frequencies there are several branches of dispersion curves corresponding to the lower layers of different stiffness in the pavement system. The observed behavior of multimodal dispersion curves is in agreement with theory, which has been validated through both numerical modeling and the transfer matrix method, by solving for complex wave numbers. ?? ASCE / JUNE 2004.

Ryden, N.; Park, C.B.; Ulriksen, P.; Miller, R.D.

2004-01-01

235

Pavement macrotexture estimation using principal component analysis of tire/road noise  

NASA Astrophysics Data System (ADS)

An investigation on the prediction of macrotexture Mean Texture Depth (MTD) of pavement from a moving vehicle is conducted. The MTD was predicted by using the tire/road noise measured from a microphone mounted underneath a moving vehicle. Principal Component Analysis (PCA) is used to filter noise from microphone data prioer to estimating its energy over an optimally selected bandwidth. Energy obtained using this method is named PCA energy, hence the developed method for MTD estimation is termed as PCA Energy Method. The acoustic energy is assumed to have positive linear correlation with MTD of pavement. Moreover, PCA was used to differentiate important information about the road surface from noisy data while vehicle is moving, yielding a set of principal component vectors representing the conditions of each road section. This principal component vector was used to compute the PCA energy that is to be used for MTD prediction. The frequency band most relative to pavement macrotexture was determined to be 140 to 700 Hz through theoretical and statistical research. Then, a MTD prediction model was built based on a Taylor series expansion with two variables, PCA energy and the driving speed of the vehicle. The model parameters were obtained from an engineered track (interstate highway) with known MTD, and then applied to urban roads for the feasibility test. The accuracy of the model is 83.61% for the engineered track, which is 10% higher than the previous energy-based methods without PCA treatment. Moreover, applicability of the model is increased by the extended MTD prediction range between 0.2 and 3 mm compared to that of the engineered track having 0.4 to 1.5 mm. In addition, the MTD could be predicted every 7.8 meters and with good repeatability in the urban road test, which proves the feasibility of the proposed approach. Therefore, the PCA Energy Method is a reliable, efficient, and cost effective way to predict MTD for engineering applications as an important index for pavement friction prediction and pavement segregation identification.

Zhang, Yiying; McDaniel, J. Gregory; Wang, Ming L.

2014-04-01

236

The effect of carbonation after demolition on the life cycle assessment of pavements  

E-print Network

The high contribution of CO? emissions associated with pavements has driven research to assess the life cycle of concrete versus asphalt structures and to develop a strategy to reduce the carbon footprint. The life cycle ...

Rossick, Katelyn M

2014-01-01

237

Signatures for several types of naturally occurring radioactive materials.  

PubMed

Detectors to scan for illicit nuclear material began to be installed at various screening locations in 2002. On the sites considered, each vehicle drives slowly by radiation detectors that scan for neutron and gamma radiation, resulting in a time series profile. One performance limitation is that naturally occurring radioactive materials (NORM), such as cat litter, are routinely shipped across borders, leading to nuisance alarms. One strategy for nuisance alarms is to define and recognize "signatures" of certain types of NORM so that many nuisance alarms can be quickly resolved as being innocent. Here, we consider candidate profile features, such as the peak width and the maximum energy ratio, and use pattern recognition methods to illustrate the extent to which several common types of NORM can be distinguished. PMID:18378153

Burr, Tom; Myers, Kary

2008-09-01

238

Model studies of stresses in upper layers of pavements  

E-print Network

t A ugu st 1955 L I B R A R Y A & M COLLEGE OF TEXAS MODEL STUDIES OF STRESSES IN UPPER LAYERS OF PAVEMENTS A D is s e r ta t io n B y BHUPATIRAJU SUBBARAJU Subm itted to the G raduate S ch oo l o f the A g r i c u l tu r a l... and M ech an ica l C o l l e g e o f T e x a s in p a r t ia l fu l f i l lm en t o f the r e q u ir em en ts f o r the d e g re e DOCTOR OF PH ILOSOPHY August 1955 M a jo r Sub ject : C iv i l E ng in eer in g rw V' i ACKNOWLEDGMENT...

Subbaraju, Bhupatiraju

1955-01-01

239

The impact of maintenance and rehabilitation strategies on the pavement network value  

E-print Network

The maintenance and rehabilitation of road infrastructure demands a great investment of time and money. The deterioration of pavement condition over time due to environmental factors and increasing traffic loads combined with the limitation of funds...

Chang Albitres, Carlos Martin

1999-01-01

240

An analysis of pavement heat flux to optimize the1 water efficiency of a pavement-watering method2  

E-print Network

heat wave intensity and frequency. However,13 although water consumption necessary to implement; pavement heat flux; pavement-watering; urban heat island; climate change25 adaptation; heat wave26 1. In France and especially Paris, the predicted increases in heat32 wave intensity and frequency due

Paris-Sud XI, Université de

241

Measurement of mixing efficiency in pavement recycling  

SciTech Connect

This dissertation covers an extensive evaluation of a wide range of ideas for measuring the extent of mixing during a recycling operation. A number of test methods including the resilient modulus (M/sub R/), dye chemistry, fluorescence spectroscopy, ultrasonic scanning, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), X-ray image analysis, electron microscopy, and chromatography were evaluated. The study ws primarily aimed at the development of a test method that could be conducted in the field with a minimum of equipment and training. It is a pioneering effort with regard to the mixing efficiency of the recycling process. The dye chemistry technique appears conclusively to be a straightforward, rapid and inexpensive test method. The resulting dye prints were evaluated either by visual examination or by densitometric scanning. Differences of various mixing patterns in terms of dye dispersion can be measured qualitatively and quantitatively. Ten field projects were conducted to demonstrate the applications of such technique to full-scale construction conditions. The overall mixing efficiency of a specific operation can be appraised by statistically analyzing the resulting dye distributions. Consequently, optimization of the mixing process or the plant design may be achieved through such knowledge.

Lee, T.C.

1982-01-01

242

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

SciTech Connect

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.

Cheng, C.M.; Taerakul, P.; Tu, W.; Zand, B.; Butalia, T.; Wolfe, W.; Walker, H. [Western Kentucky University, Bowling Green, KY (United States)

2008-08-15

243

Validation and development of guidelines to select MRR strategies for rigid pavements  

E-print Network

Maintenance, rehabilitation and reconstruction (MRR) work to rigid pavement roadways requires a great demand of time, effort, and money. The nature of this work not only affects state highway agencies (SHAs) but also, roadway users and local...

Herrera, Edgar Efren

2001-01-01

244

The development of correlations between HMA pavement performance and aggregate shape properties  

E-print Network

The physical characteristics of aggregates (form, angularity, and texture) are known to affect the performance of hot mix asphalt (HMA) pavements. Efforts to develop relationships between these aggregate characteristics and aggregate performance...

McGahan, Jeremy

2006-04-12

245

SEMICONDUCTOR MATERIALS: NTC and electrical properties of nickel and gold doped n-type silicon material  

NASA Astrophysics Data System (ADS)

Silicon materials compensated by deep level impurities such as nickel and gold have negative temperature coefficient (NTC) characteristics. In this work, n-type silicon wafers are smeared by nickel chloride ethanol solution and gold chloric acid ethanol solution, and subsequently put in the opening environment to heat. The electrical resistance and B-value of the thermistors made by this silicon material are measured and analyzed. When the silicon surface concentration of gold atoms is 2 × 10-6 mol/cm2, the uniformity of the single-crystal silicon material is optimal. When the diffusion temperature is between 900 and 1000 °C, a material with high B-value and low electrical resistivity is obtained. The B-T and R-T change laws calculated by the theory of semiconductor deep level energy are basically consistent with the experimental results.

Maojin, Dong; Zhaoyang, Chen; Yanwei, Fan; Junhua, Wang; Mingde, Tao; Xiuyun, Cong

2009-08-01

246

Pavement Smoothness for Illinois DOT -Doug Dirks 1. Briefly summarize your current pavement smoothness requirements. See below.  

E-print Network

Pavement Smoothness for Illinois DOT - Doug Dirks 1. Briefly summarize your current pavement? N/A Illinois has both standard specifications and a special provision for pavement smoothness-Depth HMA Pavement 407.09 PCC Pavement 420.10 The following is a link to Division 400 of the Illinois

247

A decision process framework: selecting strategies for rehabilitation of rigid pavements subjected to high traffic volumes  

E-print Network

fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2000 Major Subject: Civil Engineering A DECISION PROCESS FRAMEWORK: SELECTING STRATEGIES FOR REHABILITATION OF RIGID PAVEMENTS SUBJECTED TO HIGH TRAFFIC VOLUMES A Thesis MARC...) Donald A. Maxwell (Member) Kenneth . Williamson (Member) Jo . iedzwecki (Head of Department) August 2000 Major Subject: Civil Engineering ABSTRACT A Decision Process Framework: Selecting Strategies for Rehabilitation of Rigid Pavements...

Valls, Marc Edouard Josep

2000-01-01

248

Bearing capacity of unpaved roads  

Microsoft Academic Search

Elastic layer theories may be valid for relatively stiff pavement materials and pavements subjected to low traffic stresses; however, the assumption of linear elastic behavior is not suitable for thin pavements and unpaved roads consisting of untreated granular bases over cohesive subgrades. The behavior of such pavements, even at low traffic stresses, is markedly nonlinear. Pavement design methods based on

Simon Y. Oloo; D. G. Fredlund; J. K.-M. Gan

1997-01-01

249

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...

250

Flexible Pavement Drainage Monitoring, Performance, and Stability  

Microsoft Academic Search

The current study is a continuation of the study FHWA\\/IN\\/JTRP project HPR-2078, “Locating the Drainage Layer for Flexible Pavements”. In this previous study, three test sections were constructed in a new pavement on a by-pass around Fort Wayne, Indiana. These test sections were instrumental to record temperatures, moisture, frost penetration, rainfall and subdrainage system overflow. Collected data and Finite Element

Aiwen Feng; Jianfeng Hua; Thomas D. White

1999-01-01

251

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

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 quickly, whereas less active sites, such as the bulldozed tracks at Marble Point, and Williams Field to McMurdo Station pipeline site on Ross Island, showed only intermediate recovery 20-30 years after disturbance. The slabby grano-diorite surface material at the former Vanda Station site, meant that the impacts that had occurred were hard to detect following decommissioning of the station and site remediation. Desert pavements disturbed by randomly dispersed footprints, temporary field campsites at the Loop Moraine and VXE6 Pond in the Wright Valley, recovered to be undetectable (MRI = 100%) within five years, whereas track formation from repeated trampling, particularly the concentration of larger clasts along the margin of a confined track, persisted for over 15 years (MRI = 82%). The recovery assessment method developed in this study has environmental management applications and potential to advance our ability to predict the recovery of desert pavement following human impacts from activities in Antarctica. PMID:23000478

O'Neill, Tanya A; Balks, Megan R; López-Martínez, Jerónimo; McWhirter, Judi L

2012-12-15

252

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

USGS Publications Warehouse

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 ?g/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.

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

2014-01-01

253

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

SciTech Connect

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.

Chen, J.S.; Tsai, C.J. [National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Civil Engineering] [National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Civil Engineering

1998-12-01

254

Theoretical and field evaluation of interaction between ultra-thin whitetopping and existing asphalt pavement  

Microsoft Academic Search

Ultra-thin concrete overlays or ultra-thin whitetopping (UTW), are an attractive alternative to traditional practices for the rehabilitation of asphalt pavements. However, it is widely accepted that the exiting pavement should have substantial stiffness to make a UTW a rehabilitation option. This paper re-examines this hypothesis using the performance results and structural evaluation of two experimental sections in Brazil. It is

Deividi Da S. Pereira; José T. Balbo; Lev Khazanovich

2006-01-01

255

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

NASA Astrophysics Data System (ADS)

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 Austrian Science Fund (FWF grants P21414-B16 and P25365-B25).

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

2014-05-01

256

Laboratory analysis of the infiltration capacity of interlocking concrete block pavements in car parks.  

PubMed

Interlocking concrete block pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (R(SL)) and surface slope (S(S)). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25 m(2) for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the R(SL) and S(S) variables. All models passed a confidence level of 95%, presenting high R(2) values and showing that R(SL) is a more influential variable than the S(S) for all clogging scenarios. PMID:23202575

Sañudo-Fontaneda, Luis A; Rodriguez-Hernandez, Jorge; Vega-Zamanillo, Angel; Castro-Fresno, Daniel

2013-01-01

257

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

PubMed Central

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

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

2015-01-01

258

Elastic and plastic properties of soils influencing the design of rigid pavements  

E-print Network

of Theor ie s of R ig id Pavement Design 2. A ssumptions Relative to Soil Behavior 3. Indications of Lack of Continuous Support 4. Bas ic O b j e c t i v e s ........................................... B. Se lection of A Site fo r S t u d y... s t s .................................................. 89 IV. PLASTIC AND ELASTIC STRAINS EXPERIENCED BY THE S O I L .....................................................................................................102 A . Magnitude o f the E lastic and P la s t ic Strains . . . . 1 0 2 B...

Khuri, Fuad I.

1954-01-01

259

Structure elucidation of alkaline earth impregnated MCM-41 type mesoporous materials obtained by direct synthesis: An experimental and theoretical study  

NASA Astrophysics Data System (ADS)

In this work, MCM-41 were synthesized hydrothermally and functionalized with calcium and strontium salts by direct method, using the Si/M = 50 molar ratio, in order to elucidate the way as the alkaline earth is incorporated on MCM-41 molecular sieve. The materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nitrogen adsorption-desorption and theoretical calculations by DFT method. Experimental results and computer simulations showed that the alkaline earths were incorporated on MCM-41 through a complex structure, which negatively influences on basic sites formation.

Paz, Gizeuda L.; Silva, Francisco das Chagas M.; Araújo, Maciel M.; Lima, Francisco das Chagas A.; Luz, Geraldo E.

2014-06-01

260

Fusing complementary images for pavement cracking measurements  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

261

Electro-optical approach to pavement deflection management  

NASA Astrophysics Data System (ADS)

A prototype continuous deflection device, referred to as a rolling weight deflectometer (RWD), has been developed as a nondestructive evaluation tool for airfield pavements. The system consists of a rigid trailer equipped with specially designed optical triangulation pavement sensors, a high-speed data acquisition system, and a high-pressure tire/load platform assembly. Pavement sensors are mounted on a rigid box beam equipped with an internal sensor system that corrects, in real time, the relative pavement height position measurements for displacements induced in the beam by mechanical vibrations, changes in temperature, or nonuniform dynamic loads at points where the beam attaches to the frame. The device produces continuous deflection profiles that show pavement response to a moving loaded wheel along the path of travel. These deflection profiles, combined with multiple passes along a lane, provide a far more detailed picture of the pavement structural integrity than has ever before been possible, because existing evaluation tools only produce response information at discrete points. Preliminary results show deflections measured by the RWD are in general agreement with the expected pavement response for various loads. A discussion of the device configuration, preliminary data, and potential as a pavement management tool is presented.

Rish, Jeff W., III; Adcock, Avery D.; Tuan, Christopher Y.; Baker, Samuel L.; Welker, Hugh W., II; Johnson, Roger F.

1995-07-01

262

Pavement recycling guidelines for state and local governments: Participant`s reference book. Final report, September 1995--December 1997  

SciTech Connect

Recycling or reuse of existing asphalt pavement materials to produce new pavement materials has the following advantages: (1) reduced costs of construction, (2) conservation of aggregate and binder, (3) preservation of the existing pavement geometrics, (4) preservation of the environment, and (5) conservation of energy. This document was prepared to provide the following information on recycling of asphalt pavements: (1) performance data, (2) legislation/specification limits, (3) selection of pavement for recycling and recycling strategies, (4) economics of recycling, and (5) structural design of recycled pavements. The following recycling methods have been included: hot-mix asphalt recycling (both batch and drum plants), asphalt surface recycling, hot-in-place recycling, cold-mix asphalt recycling, and full depth reclamation. Materials and mix design, construction methods and equipment, case histories and quality control/quality assurance have been discussed for all recycling methods.

Kandhal, P.S.; Mallick, R.B.

1997-12-01

263

Development of statistical wet weather model to evaluate frictional properties at the pavement-tire interface on hot mix asphalt concrete  

E-print Network

Skid resistance on wet pavements is influenced by friction at the tire-pavement interface as well as overall hot mix asphalt (HMA) performance. It is important to control aggregate, asphalt, and mix properties to achieve desirable frictional...

Bedi, Harpreet

2001-01-01

264

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

USGS Publications Warehouse

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 (?PAH8) 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 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 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 ?PAH8 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.

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

265

Thickness estimation of subsurface layers in asphalt pavement using monstatic ground penetrating radar  

E-print Network

parameters 3. 2 Reflection and transmission of TEM plane wave. . . 3. 3 Wave propagation in multilayer medium. IV FORWARD MODELING . . 4. 1 Assumptions. 4. 2 Forward modeling. 4. 3 Applications of forward modeling. V CALCULATION OF PAVEMENT LAYER...-1) ( d' ) 2 m (3. 1. 5) (3. 1. 6) respectively, (3. 1. 2) can be expressed as E = Ep e o e-II)z (3. 1. 7) Equation (3. 1. 5) and (3. 1. 6) will be used in forward modeling to calculate the attenuation and the dispersion caused by the lossy...

Lau, Chun Lok

1991-01-01

266

Detection of circumstellar material in a normal type Ia supernova.  

PubMed

Type Ia supernovae are important cosmological distance indicators. Each of these bright supernovae supposedly results from the thermonuclear explosion of a white dwarf star that, after accreting material from a companion star, exceeds some mass limit, but the true nature of the progenitor star system remains controversial. Here we report the spectroscopic detection of circumstellar material in a normal type Ia supernova explosion. The expansion velocities, densities, and dimensions of the circumstellar envelope indicate that this material was ejected from the progenitor system. In particular, the relatively low expansion velocities suggest that the white dwarf was accreting material from a companion star that was in the red-giant phase at the time of the explosion. PMID:17626848

Patat, F; Chandra, P; Chevalier, R; Justham, S; Podsiadlowski, Ph; Wolf, C; Gal-Yam, A; Pasquini, L; Crawford, I A; Mazzali, P A; Pauldrach, A W A; Nomoto, K; Benetti, S; Cappellaro, E; Elias-Rosa, N; Hillebrandt, W; Leonard, D C; Pastorello, A; Renzini, A; Sabbadin, F; Simon, J D; Turatto, M

2007-08-17

267

Determining material damping type by comparing modal frequency estimators.  

PubMed

The accuracy of modal frequency and damping estimators for non-lightly damped single degree of freedom systems depend on the response parameter used as well as the damping mechanism. Therefore, in order to make accurate modal parameter measurements, the damping mechanism at play must be known to be either viscous or hysteretic a priori. Here, comparisons between the evaluated frequency values are used to glean this information. The damping mechanism of an experimental system (consisting of resilient layer and mass plate) is then determined using two simple modal parameter estimators and applying statistical methods. PMID:19739703

Anthony, D K; Simón, F; Juan, Jesús

2009-09-01

268

Binzhou Perpetual Pavement Test Road  

Microsoft Academic Search

Expressway construction has been carried out on a large-scale in China. Vigorous economical development has caused rapid growth in traffic volume and truck axle loads creating a severe challenge for the pavement structure design. Therefore, the high-performance and low- maintenance cost of a long-life perpetual pavement structure is gaining attention. This paper discusses the first perpetual asphalt pavement test road

Yongshun Yang; Jincheng Wei; Wang Lin; David Timm; Gerald Huber

2009-01-01

269

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

PubMed

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

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

2014-01-01

270

Reactor Material Program Fracture Toughness of Type 304 Stainless Steel  

SciTech Connect

This report describes the experimental procedure for Type 304 Stainless Steel fracture toughness measurements and the application of results. Typical toughness values are given based on the completed test program for the Reactor Materials Program (RMP). Test specimen size effects and limitations of the applicability in the fracture mechanics methodology are outlined as well as a brief discussion on irradiation effects.

Awadalla, N.G.

2001-03-28

271

A new NDT tool for pavement evaluation: Step-Frequency GPR  

E-print Network

A new NDT tool for pavement evaluation: Step-Frequency GPR H. Thomas Yu Office of Asset Management, Pavement, and Construction Federal Highway Administration #12;Ground Penetrating Radar #12;The APE #12;SF-GPR mix · Material degradation Moisture detection Cover depth detection #12;GPR testing #12;Impulse vs

272

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

USGS Publications Warehouse

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 (?PAH8) 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 ?g 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.

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

273

RELIABILITY OF BASE-COURSE THICKNESS DESIGN CURVES FOR CONCRETE PAVEMENTS IN JAPAN  

NASA Astrophysics Data System (ADS)

In this study, reliability of the base-course thickness design curves in Japan were examined based on bearing capacity research results of an actual size concrete pavement / base course yard constructed in the Public Works Research Institute and the past researches. As the results, it was found that the degree of reliability of design curve of the crusher-run base and the mechanically stabilized base is 80%, 70% respectively. And it was also found that different design curve of cement-treated base would be required for each base course thickness. In addition, based on these results, the design curve of each base course materials considering reliability was proposed in this study.

Takeuchi, Yasushi; Mao, Shi-Hua; Okazawa, Hiromu; Koyanagawa, Masashi; Nishizawa, Tatsuo; Horiuchi, Satoshi

274

TOLLWAY LCCA PROCESS FOR ADDAMS MEMORIAL TOLLWAY ADDAMS EXPRESSWAY PAVEMENT RECONSTRUCTION --  

E-print Network

TOLLWAY LCCA PROCESS FOR ADDAMS MEMORIAL TOLLWAY Page 1 ADDAMS EXPRESSWAY PAVEMENT RECONSTRUCTION and for the maintenance activities anticipated over a 50-year life span for each of the pavement types under consideration and expand capacity along the Jane Addams Memorial Tollway between I-39 and the Kennedy Expressway

275

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

SciTech Connect

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.

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

1998-01-01

276

UNBURNED MATERIAL IN THE EJECTA OF TYPE Ia SUPERNOVAE  

SciTech Connect

The presence of unburned material in the ejecta of normal Type Ia supernovae (SNe Ia) is investigated using early-time spectroscopy obtained by the Carnegie Supernova Project. The tell-tale signature of pristine material from a C+O white dwarf progenitor star is the presence of carbon, as oxygen is also a product of carbon burning. The most prominent carbon lines in optical spectra of SNe Ia are expected to arise from C II. We find that at least 30% of the objects in the sample show an absorption at Almost-Equal-To 6300 A which is attributed to C II {lambda}6580. An alternative identification of this absorption as H{alpha} is considered to be unlikely. These findings imply a larger incidence of carbon in SNe Ia ejecta than previously noted. We show how observational biases and physical conditions may hide the presence of weak C II lines, and account for the scarcity of previous carbon detections in the literature. This relatively large frequency of carbon detections has crucial implications on our understanding of the explosive process. Furthermore, the identification of the 6300 A absorptions as carbon would imply that unburned material is present at very low expansion velocities, merely Almost-Equal-To 1000 km s{sup -1} above the bulk of Si II. Based on spectral modeling, it is found that the detections are consistent with a mass of carbon of 10{sup -3} to 10{sup -2} M{sub Sun }. The presence of this material so deep in the ejecta would imply substantial mixing, which may be related to asymmetries of the flame propagation. Another possible explanation for the carbon absorptions may be the existence of clumps of unburned material along the line of sight. However, the uniformity of the relation between C II and Si II velocities is not consistent with such small-scale asymmetries. The spectroscopic and photometric properties of SNe Ia with and without carbon signatures are compared. A trend toward bluer color and lower luminosity at maximum light is found for objects which show carbon.

Folatelli, Gaston; Tanaka, Masaomi; Maeda, Keiichi; Nomoto, Ken'ichi [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Phillips, M. M.; Morrell, Nidia; Campillay, Abdo; Gonzalez, Sergio; Roth, Miguel [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Stritzinger, Maximilian [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, 10691 Stockholm (Sweden); Burns, Christopher R.; Freedman, W. L.; Madore, Barry F; Persson, S. E. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Hamuy, Mario [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Mazzali, Paolo [Max-Planck Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching (Germany); Boldt, Luis [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53111 Bonn (Germany); Contreras, Carlos [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Victoria 3122 (Australia); Salgado, Francisco [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Suntzeff, Nicholas B., E-mail: gaston.folatelli@ipmu.jp [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)

2012-01-20

277

OPTIMIZATION AND TESTING OF HIGHWAY MATERIALS TO MITIGATE ICE ADHESION  

EPA Science Inventory

Field tests at the WSU Pavement Test Facility augment BBRC laboratory tests with comparative results. Factors of concern included pavement type, tire type, environment and toxicity, wear, ice/snow adhesion and asphalt overlays which included the substances as a component of the m...

278

Types and Distribution of Bright Materials in 4 Vesta  

NASA Technical Reports Server (NTRS)

A strong case can be made that Vesta is the parent asteroid of the howardite, eucrite and diogenite (HED) meteorites [1]. As such, we have over a century of detailed sample analysis experience to call upon when formulating hypotheses regarding plausible lithologic diversity on Vesta. It thus came as a surprise when Dawn s Framing Camera (FC) first revealed distinctly localized materials of exceptionally low and high albedos, often closely associated. To understand the nature and origin of these materials, and how they inform us of the geological evolution of Vesta, task forces began their study. An initial step of the scientific endeavor is to develop a descriptive, non-genetic classification of objects to use as a basis for developing hypotheses and observational campaigns. Here we present a catalog of the types of light-toned deposits and their distribution across Vesta. A companion abstract [2] discusses possible origins of bright materials and the constraints they suggest for vestan geology.

Mittlefehldt, D. W.; Li, Jian-Yang; Pieters, C. M.; De Sanctis, M. C.; Schroder, S. E.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Yingst, R. A.

2012-01-01

279

THERMAL UPGRADING OF 9977 RADIOACTIVE MATERIAL (RAM) TYPE B PACKAGE  

SciTech Connect

The 9977 package is a radioactive material package that was originally certified to ship Heat Sources and RTG contents up to 19 watts and it is now being reviewed to significantly expand its contents in support of additional DOE missions. Thermal upgrading will be accomplished by employing stacked 3013 containers, a 3013 aluminum spacer and an external aluminum sleeve for enhanced heat transfer. The 7th Addendum to the original 9977 package Safety Basis Report describing these modifications is under review for the DOE certification. The analyses described in this paper show that this well-designed and conservatively analyzed package can be upgraded to carry contents with decay heat up to 38 watts with some simple design modifications. The Model 9977 package has been designed as a replacement for the Department of Transportation (DOT) Fissile Specification 6M package. The 9977 package is a very versatile Type B package which is certified to transport and store a wide spectrum of radioactive materials. The package was analyzed quite conservatively to increase its usefulness and store different payload configurations. Its versatility is evident from several daughter packages such as the 9978 and H1700, and several addendums where the payloads have been modified to suit the Shipper's needs without additional testing.

Gupta, N.; Abramczyk, G.

2012-03-26

280

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)

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 (M?) 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 identifying features on the road. PAVEMON offers an ideal research and monitoring platform for rapid, intelligent and comprehensive evaluation of tomorrow's transportation infrastructure based on up-to-date data from heterogeneous sensor systems.

Shahini Shamsabadi, Salar

281

Polymer concrete for precast repair of continuously reinforced concrete pavement on IH 30, near Mt. Pleasant  

NASA Astrophysics Data System (ADS)

Two punchout repairs made in a continuously reinforced concrete pavement (CRCP) using precast portland cement panels are described. The two repairs, one 1.44 sq. ft., the other 36 sq. ft., were completed and opened to traffic in one afternoon. This technique provides a rapid method of repair that produces a repair that is structurally as good or better than the surrounding pavement. With a trained crew, the repair time can be reduced and thus reducing lane closure time. Since lane closure time is a critical consideration in high volume highways, this method is cost effective in those areas.

Meyer, A. M.; McCullough, B. F.; Fowler, D. W.

1981-08-01

282

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

NASA Astrophysics Data System (ADS)

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 Malaysia attains average 65 per cent only and had not achieved level that had been set by PWD Malaysia namely 80 per cent. Hence, this paper has revealed the causes of the occurrances in the pavement management system in construction project in Malaysia and investigated the consequences of the late payments and final account problems confronted by contractors in Malaysia, which eventually proposed strategic actions that could be taken by the contractors in securing their payments.

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

2013-04-01

283

Concrete Overlay as a Rehabilitation Option for Distressed Asphalt Pavements  

Microsoft Academic Search

Ultra-thin Whitetopping (UTW) involves placing a very thin concrete overlay 50 mm to 100 mm thick (2”-4”) on the milled surface of a distressed asphalt pavement. To investigate the performance of UTW placed over a flexible pavement subjected to slow and heavy moving wheel loads, whitetopping mixes were placed over a milled pavement surface in the Accelerated Pavement Testing (APT)

Sudarshan Rajan; J. Olek

2002-01-01

284

Properties of Extruded PS-212 Type Self-Lubricating Materials  

NASA Technical Reports Server (NTRS)

Research has been underway at the NASA Lewis Research Center since the 1960's to develop high temperature, self-lubricating materials. The bulk of the research has been done in-house by a team of researchers from the Materials Division. A series of self-lubricating solid material systems has been developed over the years. One of the most promising is the composite material system referred to as PS-212 or PM-212. This material is a powder metallurgy product composed of metal bonded chromium carbide and two solid lubricating materials known to be self-lubricating over a wide temperature range. NASA feels this material has a wide potential in industrial applications. Simplified processing of this material would enhance its commercial potential. Processing changes have the potential to reduce processing costs, but tribological and physical properties must not be adversely affected. Extrusion processing has been employed in this investigation as a consolidation process for PM-212/PS-212. It has been successful in that high density bars of EX-212 (extruded PM-212) can readily be fabricated. Friction and strength data indicate these properties have been maintained or improved over the P.M. version. A range of extrusion temperatures have been investigated and tensile, friction, wear, and microstructural data have been obtained. Results indicate extrusion temperatures are not critical from a densification standpoint, but other properties are temperature dependent.

Waters, W. J.; Sliney, H. E.; Soltis, R. F.

1993-01-01

285

p × n-Type Transverse Thermoelectrics: A Novel Type of Thermal Management Material  

NASA Astrophysics Data System (ADS)

In this paper we review the recently identified p × n-type transverse thermoelectrics and study the thermoelectric properties of the proposed candidate materials. Anisotropic electron and hole conductivity arise from either an artificially engineered band structure or from appropriately anisotropic crystals, and result in orthogonal p-type and n-type directional Seebeck coefficients, inducing a non-zero off-diagonal transverse Seebeck coefficient with appropriately oriented currents. Such materials have potential for new applications of thermoelectric materials in transverse Peltier cooling and transverse thermal energy harvesting. In this paper we review general transverse thermoelectric phenomena to identify advantages of p × n-type transverse thermoelectrics compared with previously studied transverse thermoelectric phenomena. An intuitive overview of the band structure of one such p × n-material, the InAs/GaSb type-II superlattice, is introduced, and the plot of thermoelectric performance as a function of superlattice structure is calculated, as an example of how band structures can be optimized for the best transverse thermoelectric performance.

Tang, Yang; Cui, Boya; Zhou, Chuanle; Grayson, Matthew

2015-03-01

286

EVALUATION OF IN-SITU VARIABILITY OF CONCRETE PAVEMENT THICKNESS AND  

E-print Network

EVALUATION OF IN-SITU VARIABILITY OF CONCRETE PAVEMENT THICKNESS AND REVISED MEASUREMENT FREQUENCY on variability of concrete layer thickness #12;Approach ·Evaluate concrete layer thickness in JPCPs using core Evaluation Location · JPCP concrete layer thickness evaluated at 3 locations in southern MN. · Described

Minnesota, University of

287

Temperature control of hot-poured sealants during the sealing of pavement cracks  

Microsoft Academic Search

Bituminous sealants are applied to asphalt concrete roadways to prevent the ingress of water, brine and debris in the road structure. This delays degradation and extends the pavement service life. Sealants are applied hot, yet little is known about temperature control and temperature variations during typical sealant installations and its affect on sealant properties and performance. To address this issue,

J. F. Masson; P. Collins; M. Lowery

2005-01-01

288

Magnetic ejection of diamagnetic sub-millimeter grains observed by a chamber-type ?G generator orientated to identify material of a single particle  

NASA Astrophysics Data System (ADS)

A principle to identify the material of a single particle without destroying the sample is examined by an experiment in microgravity ( ?G). Such an identification is important as a first stage of analyzing various grains of primitive materials. The identification was based on diamagnetic susceptibility ? DIA obtained from translation of the grain induced by a magnetic field. When a grain is released in an area of a monotonously decreasing field under ?G conditions, it will be ejected in the direction of the field reduction; here, the area is occupied with diffused gas medium. The material identification of a primitive grain is possible by comparing the measured ? DIA with published values; an intrinsic ? DIA value is assigned to a material according to a molecular orbital model. We report here that the ejection is realized for sub-mm-sized crystals of various organic and inorganic materials. By developing a short drop shaft ( ?G duration ~0.5 s), the proposed material identification can be easily performed in an ordinary chamber. Using conventional methods, ? DIA cannot be detected for a small sample of diameter below the level of a millimetre. The achieved result is a step to realize the identification of micron-sized grains that compose primitive materials.

Hisayoshi, K.; Uyeda, C.; Kuwada, K.; Mamiya, M.; Nagai, H.

2013-03-01

289

Application of Lightweight Aggregate Concrete in Old Bridge Deck Pavement Engineering  

Microsoft Academic Search

In terms of the severe phenomena arising in the bridges of our country in recent years, like decrease of bearing force, loss of pre-stress and damage of bridge deck, this paper studies the application of lightweight aggregate concrete in the old bridge deck pavement from the aspects of concrete preparation, construction technics and quality control, and probes into the key

Liu Juan-hong; Song Shao-min; Zhong Jian-feng; Chen Xiao-fang

2010-01-01

290

Automated crack control analysis for concrete pavement construction  

E-print Network

The focus of this research is on the control of random cracking in concrete paving by using sawcut notch locations in the early stages of construction. This is a major concern in concrete pavement construction. This research also addresses a...

Jang, Se Hoon

2005-11-01

291

Development of a 3-D Finite Element Program for Pavement Analysis, Volume 2: Appendix 2  

Microsoft Academic Search

A three dimensional finite element program is developed for the analysis of pavement systems. An explicit approach of the finite element analysis is adopted. This approach results in a vector formulation of the equation of motion. Large displacement is considered through the use of a co-rotational approach which considers small deformations and large rotations of the elements. For the convenience

Tatsaba Nilaward; Chiang Shih; Thomas D. White; E. C. Ting

1998-01-01

292

Development of a 3-D Finite Element Program for Pavement Analysis, Volume 3: Appendix 3  

Microsoft Academic Search

A three dimensional finite element program is developed for the analysis of pavement systems. An explicit approach of the finite element analysis is adopted. This approach results in a vector formulation of the equation of motion. Large displacement is considered through the use of a co-rotational approach which considers small deformations and large rotations of the elements. For the convenience

Tatsaba Nilaward; Chiang Shih; Thomas D. White; E. C. Ting

1998-01-01

293

LONG-TERM IN-SITU INFILTRATION PERFORMANCE OF PERMEABLE CONCRETE BLOCK PAVEMENT  

Microsoft Academic Search

SUMMARY Since it is a design criteria for road drainage and sewer systems, the infiltration performance of permeable concrete block pavement (CBP) is of important significance during the service life of a road construction. Due to the entrainment of mineral and organic fines into the pores of porous concrete blocks or into the aggregates used in joints or openings, the

Soenke Borgwardt

294

Compaction Effects on Uniformity, Moisture Diffusion, and Mechanical Properties of Asphalt Pavements  

E-print Network

fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2008 Major Subject: Civil Engineering COMPACTION EFFECTS ON UNIFORMITY, MOISTURE DIFFUSION, AND MECHANICAL PROPERTIES OF ASPHALT PAVEMENTS A... Committee Members, Robert Lytton Amy Epps Martin Ibrahim Karaman Head of Department, David Rosowsky December 2008 Major Subject: Civil Engineering...

Kassem, Emad Abdel-Rahman Ahmed

2011-08-08

295

Decomposition of tree leaf litter on pavement: implications for urban water quality  

E-print Network

Decomposition of tree leaf litter on pavement: implications for urban water quality Sarah E. Hobbie decomposition and nutrient release from leaf litter that falls on impervious surfaces is important environment of the street gutter. We compared decomposition of leaf litter of five street tree species

Weiblen, George D

296

Quality of osmotically pre-treated and vacuum dried pineapple cubes on storage as influenced by type of solutes and packaging materials.  

PubMed

The quality and stability of osmotically pre-treated and subsequently vacuum dried pineapple cubes using three different solutes and packed in three different types of packaging materials on storage was evaluated. The experiment was laid out in completely randomized block design with two factors and three replications for each treatment. Treatment combinations were considered as one factor and storage interval as another factor. Pineapple cubes stored in glass bottle showed very little percentage variation in moisture content due to its high moisture barrier properties. In all treatment combination, acidity values were invariably found to increase as the storage progressed. For all three different osmotic treatments, HDPE pouch packet always showed highest acidity followed by PVDC pouch. Again among three solutes under consideration, invert sugar recorded a rapid increase in acidity than other solutes. In pineapple cubes osmotically treated with sucrose solution, the rates of decrease of total sugar content were lower than that of invert sugar and sorbitol treated pineapple cubes. The percentage decrease of total sugar content was highest when the osmotically dehydrated pineapple cubes were packed in HDPE pouch and it was least in glass bottles. There was a gradual decrease in ascorbic acid content with the extension of storage period and this decrease was statistically significant at all storage intervals up to six-month. Lowest value of ascorbic acid content (15.210 mg per 100 g initial solid) was recorded in invert sugar treated pineapple cube packed in HDPE pouch after 6 months of storage. PMID:25114348

Paul, Prodyut Kumar; Ghosh, Swapan Kumar; Singh, Dhananjay Kumar; Bhowmick, Nilesh

2014-08-01

297

Evaluation of infiltration in layered pavements using surface GPR reflection techniques  

E-print Network

Evaluation of infiltration in layered pavements using surface GPR reflection techniques K. Grotea-coupled ground penetrating radar (GPR) techniques were used to non-destructively monitor the volumetric water contained a sub-asphalt drainage layer. GPR travel time data were used to estimate the water content in each

Hubbard, Susan

298

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...

299

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...

300

Improvement of thermal cycle characteristics of a planar-type solid oxide fuel cell by using ceramic fiber as sealing material  

Microsoft Academic Search

The objective of this paper is to improve the endurance of solid oxide fuel cell (SOFC) against thermal cycles by reducing the stress caused by the difference in thermal expansion coefficients of alloy separator and electrolyte. The thermal cycle characteristics were improved by using a ceramic fiber for the sealing material. The ceramic fiber seemed to play the role of

S Taniguchi; M Kadowaki; T Yasuo; Y Akiyama; Y Miyake; K Nishio

2000-01-01

301

Desert pavement development and landscape stability on the Eastern Libyan Plateau, Egypt  

Microsoft Academic Search

Desert pavement surfaces of the eastern Libyan Plateau in central Egypt represent a stable landscape preserving Middle and Upper Paleolithic artifacts. Detailed measurements of pavement clasts indicate significant variability in clast size, density, lithology and orientation between pavements, but no spatial relationship among any of these pavement variables over the study area. Pavement characteristics are unrelated to local geomorphic features

Katherine A. Adelsberger; Jennifer R. Smith

2009-01-01

302

Model based pavement-vehicle interaction simulation for life cycle assessment of pavements  

E-print Network

Responsible for about a third of the annual energy consumption and greenhouse gas (GHG) emissions, the U.S. transportation Network needs to attain a higher level of sustainability. This is particularly true for the roadway ...

Akbarian, Mehdi

2012-01-01

303

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

PubMed

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 (?PAH(8)) 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 ?g 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. PMID:22289152

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

2012-06-01

304

Accounting for the effects of rehabilitation actions on the reliability of flexible pavements: performance modeling and optimization  

E-print Network

A performance model and a reliability-based optimization model for flexible pavements that accounts for the effects of rehabilitation actions are developed. The developed performance model can be effectively implemented in all the applications...

Deshpande, Vighnesh Prakash

2009-05-15

305

Tool developing of MRR strategy selection  

E-print Network

of them. The factors that affect pavement treatinent type selection include: traffic level, climate, required performance life, subgrade characteristics, and material cost. The matrix shown in Figure 7 schematically illustrates this framework...

Liu, Juanyu

2001-01-01

306

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

307

Multitarget detection\\/tracking for monostatic ground penetrating radar: application to pavement profiling  

Microsoft Academic Search

Monostatic ground penetrating radar (GPR) has proven to be a useful technique in pavement profiling. In road and highway pavements, layer thickness and permittivity of asphalt and concrete can be estimated by using an inverse scattering approach. Layer-stripping inversion refers to the iterative estimation of layer properties from amplitude and time of delay (TOD) of echoes after their detection. This

Umberto Spagnolini; Vittorio Rampa

1999-01-01

308

FRP Dowels for Concrete Pavements Darren Eddie, Junior Structural Engineer, Reid Crowther & Partners;  

E-print Network

= L FRP Dowels for Concrete Pavements By Darren Eddie, Junior Structural Engineer, Reid Crowther - Introduction Joints are used in concrete pavements in order to control cracking due to thermal of steel dowels due to the application of de-icing salts causes severe deterioration of concrete highway

309

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...

310

Use of shredded tires in the subbase layer of asphalt pavements  

SciTech Connect

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.

Papp, W.J. Jr.; Maher, M.H. [Rutgers Univ., Piscataway, NJ (United States). Dept. of Civil and Environmental Engineering; Baker, R.F. [New Jersey Dept. of Transportation, Trenton, NJ (United States)

1997-12-31

311

Floatability of polymer materials modulated by frothers.  

PubMed

Flotation tests of 35 polymer materials were carried out to investigate their floatability modulated by frothers. Results of flotation tests demonstrated that polymer resins and soft PVC showed high floatability, floatability of hard PVC plastics was relatively low and was related to the frothers, and there exists significant difference in the floatability of different post-consumer plastics. Flotation rate of post-consumer plastics varies from 0% to 100%. Furthermore, three-category low-energy surface (LES) was defined based on the hydrophile index of the materials involved in this paper, and an adsorption model was proposed to explain the results of flotation and to discuss the floatability of polymer materials modulated by frothers. Frother molecules are prone to adsorb on the surface of bubble rather than LES at relatively low concentration, bubble adsorbed by frother molecules is prone to approach first-category LES rather than third-category LES, and the structure of liquid film is formed on the first-category LES at large concentration. Floatability of polymer materials modulated by frothers is further discussed: frothers increase the floatability of the first-category LES but decrease the floatability of the third-category LES, while the floatability of the second-category LES is related to the type of frothers. PMID:24084102

Wang, Hui; Wang, Chong-qing; Fu, Jian-gang

2013-12-01

312

PAVEMENT TECHNOLOGY UPDATE This Technology Transfer Program  

E-print Network

the road." In recent years, increasing amounts of crumb rubber from recycled tires have been added solve the very serious problem of waste tire disposal. TECHNOLOGY TRANSFER PROGRAM SEPTEMBER 2009, VOL. 1, NO. 2 § Rubber Roads: Waste Tires Find a Home By Larry Santucci, PE Pavement Specialist

California at Berkeley, University of

313

Possibilities of ground penetrating radar usage within acceptance tests of rigid pavements  

NASA Astrophysics Data System (ADS)

Within the road pavement acceptance tests, destructive as well as non-destructive tests of individual road layers are performed to verify the standard requirements. The article describes a method for providing quick, effective and sufficiently accurate measurements of both dowel and tie bar positions in concrete pavements, using a two-channel ground penetrating radar (GPR). Measurements were carried out in laboratory and in-situ conditions. A special hand cart for field measurements, set for the testing requirements, was designed. It was verified that following the correct measuring and assessment method, it is possible to reach accuracy of determining the in-built rebar up to 1 cm in vertical direction and up to 1.5 cm per 11.5 m of measured length in horizontal direction. In the in-situ tests, GPR identification of possible anomalies due to the phase of concrete pavement laying was presented. In the conclusion, a measurement report is mentioned. The standard requirements for the position of dowels and tie bars cover maximum possible deviation of the rebar position from the project documentation in vertical and horizontal direction, maximum deflection of rebar ends to each other, and maximum translation of rebar in the direction of its longitudinal axis.

Stryk, Josef; Matula, Radek; Pospisil, Karel

2013-10-01

314

Presence of Host ICAM-1 in Human Immunodeficiency Virus Type 1 Virions Increases Productive Infection of CD4+ T Lymphocytes by Favoring Cytosolic Delivery of Viral Material  

Microsoft Academic Search

Although there is now convincing evidence that the infectivity of human immunodeficiency virus type 1 (HIV-1) is increased by incorporation of host intercellular adhesion molecule 1 (ICAM-1) in budding virions, the exact mechanism(s) through which ICAM-1 can so significantly affect HIV-1 biology remains obscure. To address this question, we focused our attention on the most proximal events in the virus

Melanie R. Tardif; Michel J. Tremblay

2003-01-01

315

Signatures for several types of naturally occurring radioactive materials  

Microsoft Academic Search

Detectors to scan for illicit nuclear material began to be installed at various screening locations in 2002. On the sites considered, each vehicle drives slowly by radiation detectors that scan for neutron and gamma radiation, resulting in a time series profile. One performance limitation is that naturally occurring radioactive materials (NORM), such as cat litter, are routinely shipped across borders,

Tom Burr; Kary Myers

2008-01-01

316

High performance p-type thermoelectric materials and methods of preparation  

NASA Technical Reports Server (NTRS)

The present invention is embodied in high performance p-type thermoelectric materials having enhanced thermoelectric properties and the methods of preparing such materials. In one aspect of the invention, p-type semiconductors of formula Zn4-xAxSb3-yBy wherein 0?x?4, A is a transition metal, B is a pnicogen, and 0?y?3 are formed for use in manufacturing thermoelectric devices with substantially enhanced operating characteristics and improved efficiency. Two methods of preparing p-type Zn4Sb3 and related alloys of the present invention include a crystal growth method and a powder metallurgy method.

Caillat, Thierry (Inventor); Borshchevsky, Alexander (Inventor); Fleurial, Jean-Pierre (Inventor)

2005-01-01

317

Pore structure and chloride permeability of concrete containing nano-particles for pavement  

Microsoft Academic Search

Pore structure and chloride permeability of concrete containing nano-particles (TiO2 and SiO2) for pavement are experimentally studied and compared with that of plain concrete, concrete containing polypropylene (PP) fibers and concrete containing both nano-TiO2 and PP fibers. The test results indicate that the addition of nano-particles refines the pore structure of concrete and enhances the resistance to chloride penetration of

Mao-hua Zhang; Hui Li

2011-01-01

318

Preparation and thermal-sensitive characteristic of copper doped n-type silicon material  

NASA Astrophysics Data System (ADS)

Copper doped n-type single-crystal silicon materials are prepared by a high temperature diffusion process. The electrical and thermal-sensitive characteristic of materials is investigated under different experimental conditions. The results show that the maximum resistivity of 46.2 ?·cm is obtained when the sample is treated at 1200 °C for 2 h with the surface concentration of the copper dopant source being 1.83 × 10?7 mol/cm2. The copper doped n-type silicon material presents a negative temperature-sensitive characteristic and the B values are about 3010–4130 K.

Yanwei, Fan; Bukang, Zhou; Junhua, Wang; Zhaoyang, Chen; Aimin, Chang

2015-01-01

319

Base reinforcement results from the addition of a geosynthetic at the bottom or within a base course to increase the structural or load-carrying capacity of a pavement system. While there is clear evidence that geosynthetic  

E-print Network

, and the analytical component aimed at identifying the sensitivity of the mechanical properties of soil course to increase the structural or load-carrying capacity of a pavement system. While there is clear, and 2) developing material specifications that incorporate the geosynthetic and soil properties

Zornberg, Jorge G.

320

The resistance to chloride penetration of concrete containing nano-particles for pavement  

Microsoft Academic Search

The resistance to chloride penetration of concrete containing nano-particles (TiO2 and SiO2) for pavement is experimentally investigated and compared with that of plain concrete, the concrete containing polypropylene (PP) fibers and the concrete containing both nano-particles and PP fibers. The test results indicate that the addition of nano-particles (TiO2 and SiO2) improves the resistance to chloride penetration of concrete. The

Mao-hua Zhang; Hui Li

2006-01-01

321

Flexural fatigue performance of concrete containing nano-particles for pavement  

Microsoft Academic Search

The flexural fatigue performance of concrete containing nano-particles for pavement is experimentally studied. Both nano-TiO2 and nano-SiO2 are respectively employed to be as the additives. For comparison, the flexural fatigue performance of plain concrete and the concrete containing polypropylene (PP) fibers is also experimentally studied in this article. The test results indicate that the fatigue lives of concretes containing nano-particles

Hui Li; Mao-hua Zhang; Jin-ping Ou

2007-01-01

322

Measurement of pavement deflection under a moving wheel utilizing scanning laser technology  

NASA Astrophysics Data System (ADS)

A review is presented of past and current technology used to measure pavement deflection. The configuration for an improved system for deflection measurement which is currently under development is presented. The rolling wheel deflectometer (RWD) based on scanning Lidar profiling is described and rationale and proposed procedures for RWD use and data analysis are presented. Also included are projected calculation procedures for backcalculation of layer moduli from a rolling wheel load.

Herr, William J.; Johnson, Wayne G.

1995-07-01

323

The impact of geology on the performance of a bituminous surfaced pavement—a case study from southeastern Nigeria  

NASA Astrophysics Data System (ADS)

One of the multi-million Naira dual carriageways in Nigeria, the Enugu-Port Harcourt expressway, has continued to experience failure at some sections, namely the stretches covering Lokpaukwu, Lokpanta, and Leru. This road section which, unlike others, does not respond to regular and routine maintenance, is concentrated on one geologic formation, the Eze Aku Shale which has been intruded by a dolerite sill. The emplacement of the dolerite sill had resulted in intense fracturing of the shales in the vicinity of the intrusions which includes portions of where the express road crosses. The road problem is most severe where the dolerite sill is traced right under and across the road. There is evidence from the study that the road problem is linked to the geological/hydrogeological conditions of the area. For example, the problematic section of the road is built on a considerably jointed, fractured and weathered shale formation as a subgrade. The subgrade ultimately has low bearing capacity. The road is almost at the foot of an escarpment where there is a concentration of natural groundwater discharge. Most of the discharge zones including natural water courses are now almost blocked resulting in increased groundwater storage and rise in water table under the highway pavement. This leads to fast deterioration of the base course materials. The dolerite sill, where it crosses the road, is less than 2 m below the grade level. It impedes vertical infiltration as well as lateral groundwater flow. Thus its position with respect to the highway grade elevation leads to an almost perpetual wetting of the base and sub-base materials.

Okagbue, C. O.; Uma, K. O.

324

Pattern recognition algorithms for density estimation of asphalt pavement during compaction: a simulation study  

NASA Astrophysics Data System (ADS)

This paper presents the application of artificial neural network (ANN) based pattern recognition to extract the density information of asphalt pavement from simulated ground penetrating radar (GPR) signals. This study is part of research efforts into the application of GPR to monitor asphalt pavement density during compaction. The main challenge is to eliminate the effect of roller-sprayed water on GPR signals during compaction and to extract density information accurately. A calibration of the excitation function was conducted to provide an accurate match between the simulated signal and the real signal. A modified electromagnetic mixing model was then used to calculate the dielectric constant of asphalt mixture with water. A large database of GPR responses was generated from pavement models having different air void contents and various surface moisture contents using finite-difference time-domain simulation. Feature extraction was performed to extract density-related features from the simulated GPR responses. Air void contents were divided into five classes representing different compaction statuses. An ANN-based pattern recognition system was trained using the extracted features as inputs and air void content classes as target outputs. Accuracy of the system was tested using test data set. Classification of air void contents using the developed algorithm is found to be highly accurate, which indicates effectiveness of this method to predict asphalt concrete density.

Shangguan, Pengcheng; Al-Qadi, Imad L.; Lahouar, Samer

2014-08-01

325

New types of nonlinear optical materials - Li3VO4- and Li3PO4-type structures  

NASA Astrophysics Data System (ADS)

Li3VO4 and LI3PO4 types of structure crystals are found as new types of nonlinear optical materials for second-harmonic generation. Their lattices are formed of only the MO4 oxygen tetrahedra, being different from other typical nonlinear optical materials that have been developed previously.

Sakata, Shin'ichi; Fujii, Itsuhiro

1991-08-01

326

An overview of waste materials recycling in the Sultanate of Oman  

Microsoft Academic Search

Various wastes and by-product materials are generated in the Sultanate of Oman including reclaimed asphalt pavement (RAP) aggregate, demolition concrete, cement by-pass dust (CBPD), copper slag, petroleum-contaminated soils (PCS), discarded tires, incinerator ash, and others. Recycling of such materials in construction is not practiced. Research data are also minimal into the potential use of selected materials in construction applications. This

R Taha; A Al-Rawas; K Al-Jabri; A Al-Harthy; H Hassan; S Al-Oraimi

2004-01-01

327

Recycling asphalt pavements. January 1975-January 1990 (a Bibliography from the COMPENDEX data base). Report for January 1975-January 1990  

SciTech Connect

This bibliography contains citations concerning the recycling of asphalt-containing pavement materials. Articles include examples of recycling asphalt pavements; performance testing of recycled paving; methods including cold in-place, cold off-site, and hot-mix recycling; additives in recycled pavement for better performance; use of scrap roofing asphalt in conjunction with recycled paving; economics of recycling; process design; and process variables. Recycling of other materials is considered in related bibliographies. (Contains 130 citations fully indexed and including a title list.)

Not Available

1990-03-01

328

A sensitivity analysis of the Texas flexible pavement system  

E-print Network

. Fractional Factorial Analysis . ANOVA GLM Ranking Comparison 9 9 . . 10 . 13 . 14 . . 15 . . 15 Definition of Variables . . 15 Reliability . Speed . . 16 . 16 CHAPTER Base Thickness Traffic Plasticity Index Subgrade Modulus Surface... Thickness . Shoulder Type. . . . . . . . . . . . . . . AC Type . . % Voids/% AC Granular Base Modulus Month of Granular Base Modulus % Passing 4200 Vll Page 16 . . 18 . . 19 . . 19 . . 19 . . 19 . . 20 . . 20 . . 20 . . 20 21 111...

Henry, Claude Patrick

1991-01-01

329

The falling weight deflectometer (FWD) test is one of the most com-monly used tools for nondestructive evaluation of flexible pavements.  

E-print Network

for nondestructive evaluation of flexible pavements. Although the test is intrinsically dynamic, the stateThe falling weight deflectometer (FWD) test is one of the most com- monly used tools in estimation of the pavement's stiffness characteristics. Because of the decided dynamic nature of the FWD test

Guzina, Bojan

330

Synthesis and properties of Nasicon-type materials  

Microsoft Academic Search

Various composition of Na1+xSixZr2P3?xO12 (x from 1.6 to 2.4), Y-doped Nasicon (Na1+x+yZr2?yYySixP3?xO12, Na1+xZr2?yYySixP3?xO12?y, where x = 2, y = 0.12) and Fe-doped Nasicon (Na3Zr2\\/3Fe4\\/3P3O12) were prepared by coprecipitating. Differential thermal analysis (DTA), thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy (IS) were used as experimental techniques.In order to obtain Nasicon materials free

A. Ignaszak; P. Pasierb; R. Gajerski; S. Komornicki

2005-01-01

331

Early age delamination in concrete pavements made with gravel aggregates  

E-print Network

Gravel aggregates had been used extensively in the Houston District of Texas Department of Transportation (TxDOT) for continuously reinforced concrete pavements construction for many years. However, some of these pavements have been subject to early...

Liu, Juanyu

2009-06-02

332

PZT active health monitoring for fatigue accumulative damage of concrete beam containing nano-particles for pavement  

NASA Astrophysics Data System (ADS)

Based on the actuation and sense function of piezoceramic materials, PZT active health monitoring for fatigue accumulative damage of concrete beam containing nano-particles (TiO II) for pavement is experimentally studied. The test results indicate that the vibration signals received by PZT patches have three development stages obviously: the damage-formation stage, the damage-steady-growth stage and the damage-sharp-growth stage, which shows that PZT patch can monitor the whole course of the formation and growth of cracks in concrete and the failure of concrete beam. The fatigue damage index of concrete based on wavelet packet decomposition is established, and its change trend is similar to that of fatigue damage of concrete. In the range of 0%-10% of fatigue life, the damage index is approximately zero, which means that the concrete beam is basically in a healthy state and internal cracks are germinating. In the range of 10%-90% of fatigue life, the damage index increases from zero to a smaller value slowly, which means that the cracks in concrete propagate slowly. After the 90% of fatigue life, the damage index increases rapidly, which means that the cracks in concrete extend sharply and run through up to the fracture failure of concrete beam. The magnitude of damage index can show the serious extent of fatigue damage in concrete and the healthy status of concrete. The fatigue damage in concrete can be located by comparing the amplitude character of break signals or the change regularity of damage indices of PZT patches attached on concrete beam in different position. Moreover, the smaller the distance of PZT patch from the damage is, the more obvious the signal break and the change of damage index of PZT patch are, and the more sensitive the identification of PZT patch to the damage is.

Zhang, Mao-hua; Li, Hui; Ou, Jin-ping

2007-01-01

333

The type-material of Arctiinae (Lepidoptera, Erebidae) described by Burmeister and Berg in the collection of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia (Buenos Aires, Argentina)  

PubMed Central

Abstract Carlos G. Burmeister and Carlos Berg were among the most important and influential naturalists and zoologists in Argentina and South America and described 241 species and 34 genera of Lepidoptera. The Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN) housed some of the Lepidoptera type specimens of these authors. In this study we present a catalogue with complete information and photographs of 11 Burmeister type specimens and 10 Berg type specimens of Phaegopterina, Arctiina and Pericopina (Lepidoptera, Erebidae, Arctiinae, Arctiini) housed in the MACN. Lectotypes or holotypes were designated where primary type specimens could be recognized; in some cases we were not able to recognize types. The catalogue also proposes nomenclatural changes and new synonymies: Opharus picturata (Burmeister, 1878), comb. n.; Opharus brunnea Gaede, 1923: 7, syn. n.; Hypocrisias jonesi (Schaus, 1894), syn. n.; Leucanopsis infucata (Berg, 1882), stat. rev.; Paracles argentina (Berg, 1877), sp. rev.; Paracles uruguayensis (Berg, 1886), sp. rev. PMID:25061380

Beccacece, Hernán M.; Vincent, Benoit; Navarro, Fernando R.

2014-01-01

334

The importance of the glass transition temperature in relation to the low-temperature fracture resistance of asphalt and sulphlex pavement binders  

E-print Network

THE IMPORTANCE DF THE GLASS TRANSITION TEMPERATURE IN RELATION TO THE LOW-TEMPERATURE FRACTURE RESISTANCE OF ASPHALT AND SULPHLEX PAVEMENT BINDERS A Thesis by DOUGLAS LEE SMITH Submitted to the Graduate College of Texas ASM University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1985 Major Subject: Civil Engineering THE IMPORTANCE OF THE GLASS TRANSITION TEMPERATURE IN RELATION TO THE LOW-TENPERATURE FRACTURE RESISTANCE OF ASPHALT AND SULPHLEX...

Smith, Douglas Lee

1985-01-01

335

MANUAL FOR WEB-BASED TXDOT RIGID PAVEMENT Sureel Saraf  

E-print Network

NOT INTENDED FOR CONSTRUCTION, BIDDING, OR PERMIT PURPOSES. Research Supervisor: Moon Won #12;#12;Web evaluation of portland cement concrete (PCC) pavement. For example, in the mechanistic-empirical pavement

Texas at Austin, University of

336

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 ...

337

Effects of electrical conductivity of substrate materials on microstructure of diamond-like carbon films prepared by bipolar-type plasma based ion implantation  

NASA Astrophysics Data System (ADS)

Diamond-like carbon (DLC) films are prepared by a bipolar-type plasma based ion implantation, and the structural differences between DLC films deposited on different electrical conductive substrates, i.e., conductive Si wafers and insulating glass plates are examined by Raman spectroscopy and x-ray photo emission spectroscopy (XPS). In the Raman measurements, graphite (G) and disorder (D) peaks are observed for both samples. However, the additional photo luminescence is overlapped on the spectra in the case of on-glass sample. To elucidate the structural difference, the intensity ratio of D to G peak (I(D)/I(G)), G peak position and full width at half maximum (FWHM) are obtained by curve fitting using Gaussian function and linear baseline. It is found that the I(D)/I(G) is lower, G peak position is higher and FWHM of G peak is narrower for on-glass sample than for on-Si sample. According to Robertson [1], lower I(D)/I(G) seems more sp3 C-C bonding in amount for on-glass sample. In contrast, higher G peak position and narrower FWHM of G peak suggest less sp3 C-C bonding in amount for on-glass sample. The results of XPS analysis with C1s spectra reveal that sp3 ratio, i.e., the intensity ratio of sp3/(sp3+sp2) is smaller for on-glass sample than for on-Si sample. The inconsistency of the trend between I(D)/I(G) and other parameters (G peak position and FWHM of G peak) might be caused by the overlap of photo luminescence signal on Raman spectrum as to on-glass sample. From these results, it is considered that sp3 C-C bonding is reduced in amount when using insulating substrate in comparison with conductive substrate.

Nakao, S.; Sonoda, T.

2013-03-01

338

MgSrSi-Type Compounds as a Possible New Family of Thermoelectric Materials  

NASA Astrophysics Data System (ADS)

We calculated electronic structures and transport properties of 33 Zintl phase compounds M1M2X (M1, M2 = Li, Na, Mg, K, Ca, Rb, Sr, Ba; X = Si, Ge, As, Se, Sn, Sb, Te, Pb, Bi) having orthorhombic MgSrSi-type (PbCl2-type) structure. These compounds were calculated to be narrow-gap semiconductors or semimetals. By comparison with known thermoelectric materials, our analysis showed that these compounds are promising candidate new thermoelectric materials, when heavily doped with holes or electrons. The weak chemical bonds and the variety in constituent elements indicate the possibility to achieve high thermoelectric figure of merit.

Katsura, Yukari; Takagi, Hidenori

2013-07-01

339

Rutting Performance of Airport Hot-Mix Asphalt Characterized by Laboratory Performance Testing, Full-Scale Accelerated Pavement Testing, and Finite Element Modeling  

E-print Network

Hot Mix Asphalt (HMA) laboratory mixture design is intended to provide a durable, rut-resistant mixture for a given traffic type. Current mixture design procedures using the Superpave Gyratory Compactor (SGC) rely on volumetric properties...

Rushing, John Ford

2014-04-25

340

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR)  

E-print Network

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement

Shan, Jie

341

Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes  

USGS Publications Warehouse

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.

Van Metre, Peter C.; Mahler, Barbara J.

2010-01-01

342

Stormwater harvesting for irrigation purposes: an investigation of chemical quality of water recycled in pervious pavement system.  

PubMed

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

Nnadi, Ernest O; Newman, Alan P; Coupe, Stephen J; Mbanaso, Fredrick U

2015-01-01

343

A Bayesian approach for improved pavement performance prediction  

Microsoft Academic Search

We present a method for predicting future pavement distresses such as longitudinal cracking. These predicted distress values are used to plan road repairs. Large inherent variability in measured cracking and an extremely small number of observations are the nature of the pavement cracking data, which calls for a parametric Bayesian approach. We model theoretical pavement distress with a sigmoidal equation

Eun Sug Park; Roger E. Smith; Thomas J. Freeman; Clifford H. Spiegelman

2008-01-01

344

Processing of carbonaceous material by fogs  

NASA Astrophysics Data System (ADS)

Over the last years our understanding of carbonaceous material in aerosols, fogs and clouds has substantially improved. Comprehensive analytical approaches coupling chromatographic separations to bulk carbon measurements (total/dissolved organic carbon, TOC/DOC) and functional group characterization techniques (FT-IR, NMR), developed in water and soil chemistry, have been applied to atmospheric samples. We will present novel insights on the composition of carbonaceous materials in fogs using size exclusion chromatography coupled to inline TOC detection (SEC-DOC) and spectroscopic approaches like fluorescence excitation emission matrices or H-NMR spectroscopy. SEC-DOC revealed similarities of fog water organic matter to the water soluble fraction of ambient aerosols (WSOC). However some notable differences have also been observed that will be discussed. Time resolved fog sampling allowed the observation of intra-event variability of organic matter concentrations and composition including changes in molecular size. The latter being particularly interesting as it might provide observational evidence of SOA generation or oligomerization type reactions. Observations of carbonaceous particulate matter during foggy periods including pre-, interstitial and post-fog aerosol, allowed to gain insights on the impact of fog processing on carbonaceous matter and on the scavenging of carbonaceous matter by fogs. Observations made during a recent field campaign in Fresno (CA) will be discussed in detail.

Herckes, P.; Hutchings, J. W.; Wang, Y.; Hill, H.; Wang, J.; Westerhoff, P. W.

2010-07-01

345

Complex Modulus Prediction of Asphalt Concrete Pavement Cores  

E-print Network

and Texas field cores and three types of asphalt mixtures including hot mix asphalt (HMA), foaming warm mix asphalt (FWMA), and Evotherm warm mix asphalt (EWMA) were used. There were nearly forty field cores with different aging times from these three...

Ling, Meng

2013-12-02

346

Porous Pavement in Cold Climates Part: Performance and Cost  

E-print Network

Porous Pavement in Cold Climates Part: Performance and Cost Onondaga Environmental Institute 17 However, a large number of installations STILL continue to be sub-standard 4 #12;Porous Pavement Design Overview Porous pavements for new and redevelopment are a watershed- based strategy that can both mitigate

347

Multi-period optimization of pavement management systems  

E-print Network

planning periods (3-5 years) are considered; (2) the effects of future resource supplies such as budget and frequency of activities on the present management schedule are not considered; and (3) state-of-the art mathematical techniques... developed for solving multi dimensional binary knapsack type problems will be reviewed, and summarizing remarks will be described. Nemhauser and Wolsey (1988) explained an almost complete line of algorithms for a variety of 0-1 integer programming...

Yoo, Jaewook

2004-09-30

348

Temperature Dependent Tensile Fracture Stress of n- and p-Type Filled-Skutterudite Materials  

SciTech Connect

While materials with excellent thermoelectric performance are most desirable for higher heat to electrical energy conversion efficiency, thermoelectric materials must also be sufficiently mechanically robust to withstand the large number of thermal cycles and vibrational stresses likely to be encountered while in service, particularly in automotive applications. Further these TE materials should be composed of non-toxic and naturally abundant constituent elements and be available as both n- and p-type varieties. Skutterudite based thermoelectric materials seemingly fit this list of criteria. In this contribution we report on the synthesis, tensile fracture strengths, low temperature electrical and thermal transport properties, and coefficients of thermal expansion (CTE), of the n-type skutterudite La{sub 0.05({+-}0.01)}Ba{sub 0.07({+-}0.04)}Yb{sub 0.08({+-}0.02)}Co{sub 4.00({+-}0.01)}Sb{sub 12.02({+-}0.03)} and the p-type Ce{sub 0.30({+-}0.02)}Co{sub 2.57({+-}0.02)}Fe{sub 1.43({+-}0.02)}Sb{sub 11.98({+-}0.03)}. Both materials have tensile fracture strengths that are temperature independent up to 500 C, and are in the range of {approx}140 MPa as measured by a three point bend flexure test fixture described herein. The CTE's were measured by dual rod dilatometry and were determined to be 10.3 ppm/C for the n-type material and 11.5 ppm/C for p-type up to 450 C.

Salvador, James R. [GM R& D and Planning, Warren, Michigan; Yang, Jihui [General Motors Corporation; Wereszczak, Andrew A [ORNL; Wang, Hsin [ORNL; Cho, Jung Y [GM R& D and Planning, Warren, Michigan

2011-01-01

349

Dopant type and/or concentration selective dry photochemical etching of semiconductor materials  

DOEpatents

Disclosed is a method of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from said first material, said second material substantially not being etched during said method. The method comprises subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said conditions also being such that the resultant electronic structure of the first semiconductor material under said photon flux is sufficient for the first material to undergo substantial photochemical etching under said conditions and being such that the resultant electronic structure of the second semiconductor material under said photon flux is not sufficient for the second material to undergo substantial photochemical etching under said conditions. In a preferred mode, the materials are subjected to a bias voltage which suppresses etching in n- or p-type material but not in p- or n-type material, respectively; or suppresses etching in the more heavily doped of two n-type or two p-type materials.

Ashby, C.R.H.; Dishman, J.L.

1985-10-11

350

Leachability of dissolved chromium in asphalt and concrete surfacing materials.  

PubMed

Leachate metal pollutant concentrations produced from different asphalt and concrete pavement surfacing materials were measured under controlled laboratory conditions. The results showed that, in general, the concentrations of most metal pollutants were below the reporting limits. However, dissolved chromium was detected in leachate from concrete (but not asphalt) specimens and more strongly in the early-time leachate samples. As the leaching continued, the concentration of Cr decreased to below or close to the reporting limit. The source of the chromium in concrete pavement was found to be cement. The concentration of total Cr produced from leachate of different cement coming from different sources that was purchased from retail distributors ranged from 124 to 641mug/L. This result indicates that the potential leachability of dissolved Cr from concrete pavement materials can be reduced through source control. The results also showed that the leachability of dissolved Cr in hardened pavement materials was substantially reduced. For example, the concentration of dissolved Cr measured in actual highway runoff was found to be much lower than the Cr concentration produced from leachate of both open and dense graded concrete pavement specimens under controlled laboratory study. It was concluded that pavement materials are not the source of pollutants of concern in roadway runoff; rather most pollutants in roadway surface runoff are generated from other road-use or land-use sources, or from (wet or dry) atmospheric deposition. PMID:19604624

Kayhanian, Masoud; Vichare, Akshay; Green, Peter G; Harvey, John

2009-08-01

351

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

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).

Van Metre, Peter C.; Mahler, Barbara J.; Wilson, Jennifer T.; Burbank, Teresa L.

2008-01-01

352

Joining of advanced materials by superplastic deformation  

DOEpatents

A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

Goretta, Kenneth C. (Downers Grove, IL); Routbort, Jules L. (Hinsdale, IL); Gutierrez-Mora, Felipe (Woodridge, IL)

2008-08-19

353

On material characterization of paper coating materials by microindentation testing  

Microsoft Academic Search

Microindentation as a method for determining important material properties of paper coating materials is studied experimentally\\u000a and numerically. The bulk of the investigation is concentrated upon the short-lived elastic part of a spherical indentation\\u000a test, but determination of the failure stress of the coating is also discussed. The results indicate that microindentation\\u000a can be a powerful tool for material characterization

Christophe Barbier; Per-Lennart Larsson; Sören Östlund; Nils Hallbäck; Michael Karathanasis

2005-01-01

354

DEVELOPMENT OF A NEW TYPE A(F)RADIOACTIVE MATERIAL PACKAGING FOR THE DEPARTMENT OF ENERGY  

SciTech Connect

In a coordinated effort, the Department of Transportation (DOT) and Nuclear Regulatory Commission (NRC) proposed the elimination of the Specification Packaging from 49 CFR 173.[1] In accordance with the Federal Register, issued on October 1, 2004, new fabrication of Specification Packages would no longer be authorized. In accordance with the NRC final rulemaking published January 26, 2004, Specification Packagings are mandated by law to be removed from service no later than October 1, 2008. This coordinated effort and resulting rulemaking initiated a planned phase out of Specification Type B and Type A fissile (F) material transportation packages within the Department of Energy (DOE) and its subcontractors. One of the Specification Packages affected by this regulatory change is the UN1A2 Specification Package, per DOT 49 CFR 173.417(a)(6). To maintain continuing shipments of DOE materials currently transported in UN1A2 Specification Package after the existing authorization expires, a replacement Type A(F) material packaging design is under development by the Savannah River National Laboratory. This paper presents a summary of the prototype design effort and testing of the new Type A(F) Package development for the DOE. This paper discusses the progress made in the development of a Type A Fissile Packaging to replace the expiring 49 CFR UN1A2 Specification Fissile Package. The Specification Package was mostly a single-use waste disposal container. The design requirements and authorized radioactive material contents of the UN1A2 Specification Package were defined in 49 CFR. A UN1A2 Specification Package was authorized to ship up to 350 grams of U-235 in any enrichment and in any non-pyrophoric form. The design was specified as a 55-gallon 1A2 drum overpack with a body constructed from 18 gauge steel with a 16 gauge drum lid. Drum closure was specified as a standard 12-gauge ring closure. The inner product container size was not specified but was listed as any container that met Specification 7A requirements per 49 CFR 178.350. Specification 7A containers were required to withstand Type A packaging tests required by 49CFR173.465 with compliance demonstrated through testing, analysis or similarity to other containers. The maximum weight of the 7A product container, the radioactive content, and any internal packaging was limited to 200 lbs. The total gross weight for the UN1A2 Specification Package was limited to 350 lbs. No additional restrictions were applied. Authorization for use did not require the UN1A2 Specification Package to be tested to the Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC) required for performance based, Type A(F) packages certified by the NRC or DOE. The Type A(F) Packaging design discussed in this paper is required to be in compliance with the regulatory safety requirements defined in Code of Federal Regulations (CFR) 10 CFR 71.41 through 71.47 and 10 CFR71.71. Sub-criticality of content must be maintained under the Hypothetical Accident Conditions specified under 10 CFR71.73. These federal regulations, and other applicable DOE Orders and Guides, govern design requirements for a Type A(F) package. Type A(F) packages with less than an A2 quantity of radioactive material are not required to have a leak testable boundary. With this exception a Type A(F) package design is subject to the same test requirements set forth for the design of a performance based Type B packaging.

Blanton, P.; Eberl, K.

2008-09-14

355

Flow and noise control using porous material Type of award PhD Research Studentship  

E-print Network

Flow and noise control using porous material Type of award PhD Research Studentship Department to investigate the application of rigid and deformable (smart) porous materials for flow and noise control purposes, with emphasis on aero-structures. Porous materials offer attractive possibilities in engineering

Bristol, University of

356

Development of a 3-D Finite Element Program for Pavement Analysis, Volume I: Introduction and Appendix 1  

Microsoft Academic Search

A three dimensional finite element program is developed for the analysis of pavement systems. An explicit approach of the finite element analysis is adopted. This approach results in a vector formulation of the equation of motion. Large displacement is considered through the use of a co-rotational approach which considers small deformations and large rotations of the elements. For the convenience

Tatsaba Nilaward; Chiang Shih; Thomas D. White; E. C. Ting

1998-01-01

357

Effect of counterface material type and its topography on the tribological properties of polyimide composites  

NASA Technical Reports Server (NTRS)

Graphite fiber reinforced polyimide composite pins were slid against seven different counterfaces to determine the effect of material type on the tribological properties of polymer composites. In addition, the effect of sliding a new pin on a pre-established transfer film was investigated. The results indicated that almost a five order of magnitude difference in composite wear rate can occur just by varying the counterface material. An attempt to make all surfaces as smooth as possible was made, but due to differences in material composition this was not possible and a range of surface roughnesses were obtained. The results indicate that the smoother the surface, the lower the composite wear rate; but that small protrusions (not discernible with arithmetic surface roughness measurements) can markedly increase wear rates. A pre-established transfer film improved both run in and steady state wear rates.

Fusaro, R. L.

1985-01-01

358

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

USGS Publications Warehouse

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.

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

2015-01-01

359

Acute Toxicity of Runoff from Sealcoated Pavement to Ceriodaphnia dubia and Pimephales promelas.  

PubMed

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

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

2015-04-21

360

Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and Azaarenes in Runoff from Freshly Applied Coal-Tar-Based Pavement Sealcoat  

NASA Astrophysics Data System (ADS)

Coal-tar-based sealcoat (CT-sealcoat) is extensively applied to asphalt parking lots and driveways in the U.S. and Canada. Toxicity to fish and invertebrates of runoff from pavement to which CT-sealcoat has been freshly applied has been reported, but relatively little is known about how concentrations of chemicals in runoff change in the hours to days following sealcoat application. We measured the concentrations of 16 U.S. Environmental Protection Agency Priority Pollutant polycyclic aromatic hydrocarbons (PAHs) and 7 azaarenes in 9 samples of simulated runoff from a coal-tar-sealed test plot collected at increasing intervals from 5 hours to 16 weeks following application. Azaarenes, several of which are common constituents in coal-tar pitch, and their oxidized derivatives, azaarones, are an emerging group of little-studied heterocyclic chemicals. Runoff samples were collected by spraying 25 L of a diluted groundwater to 10 m2 on sealed pavement and retrieving the runoff downgradient where the runoff pooled against spill berms. Unfiltered samples were analyzed by GC/MS following liquid-liquid extraction. In the first sample (t=5 hr), phenanthrene had the highest concentration (130 ?g/L) among the 16 PAHs. Concentrations of the lower molecular weight (LMW) PAHs (2 and 3 ring) decreased during the 16 weeks following application, and concentrations of the higher molecular weight (HMW) PAHs (4 to 6 ring) increased, coincident with an increase in the concentration of suspended particulates. In the final sample (t=16 weeks), fluoranthene had the highest concentration (36 ?g/L) among the 16 PAHs. Of the azaarenes measured, concentrations of acridine and carbazole (107 and 750 ?g/L, respectively) in the initial sample exceeded those of any of the PAHs measured except phenanthrene; acridine and carbazole concentrations decreased over the 5 weeks to <5% of their initial values. Samples of dried sealcoat were analyzed the day of application and 5 weeks later. Samples were scraped from aluminum roofing disks that had been placed on the pavement prior to sealant application, and analyzed by GC/MS. Total PAH concentrations (sum of the 16 PAHs, ?PAH16) in the dried sealcoat decreased from 93,000 mg/kg several hours after application to 46,000 mg/kg 5 weeks after application; the loss of about 50% is consistent with that reported previously and attributed to volatilization. As in the runoff water, concentrations of PAHs in dried sealcoat collected on the day of application were dominated by phenanthrene (25% of ?PAH16); 5 weeks following application, as a result of volatilization of the lower molecular weight PAH, the PAH assemblage was dominated by fluoranthene (24% of ?PAH16). Concentrations of carbazole and dibenzothiophene, the two heterocyclic compounds measured in the dried sealcoat, were equivalent to 4% and 1% of ?PAH16. Results of the runoff sampling demonstrate that the chemistry of runoff from pavement with CT-sealcoat changes in the days to weeks following application, from a profile dominated by the more soluble and volatile LMW PAHs to one dominated by the more persistent HMW PAHs. The shift from the more bioavailable LMW PAHs to the more carcinogenic HMW PAHs indicates that modes of toxicity might change with time.

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

2013-12-01

361

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...

362

PHYSIOLOGICAL INFORMATION FOR PAVEMENT HEALTH MONITORING BASED ON SURFACE RIDE QUALITY  

NASA Astrophysics Data System (ADS)

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.

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

363

Implementation of solar-reflective surfaces: Materials and utility programs  

SciTech Connect

This report focuses on implementation issues for using solar-reflective surfaces to cool urban heat islands, with specific examples for Sacramento, California. Advantages of solar-reflective surfaces for reducing energy use are: (1) they are cost-effective if albedo is increased during routine maintenance; (2) the energy savings coincide with peak demand for power; (3) there are positive effects on environmental quality; and (4) the white materials have a long service life. Important considerations when choosing materials for mitigating heat islands are identified as albedo, emissivity, durability, cost, pollution and appearance. There is a potential for increasing urban albedo in Sacramento by an additional 18%. Of residential roofs, we estimate that asphalt shingle and modified bitumen cover the largest area, and that built-up roofing and modified bitumen cover the largest area of commercial buildings. For all of these roof types, albedo may be increased at the time of re-roofing without any additional cost. When a roof is repaired, a solar-reflective roof coating may be applied to significantly increase albedo and extend the life of the root Although a coating may be cost-effective if applied to a new roof following installation or to an older roof following repair, it is not cost-effective if the coating is applied only to save energy. Solar-reflective pavement may be cost-effective if the albedo change is included in the routine resurfacing schedule. Cost-effective options for producing light-colored pavement may include: (1) asphalt concrete, if white aggregate is locally available; (2) concrete overlays; and (3) newly developed white binders and aggregate. Another option may be hot-rolled asphalt, with white chippings. Utilities could promote solar-reflective surfaces through advertisement, educational programs and cost-sharing of road resurfacing.

Bretz, S.; Akbari, H.; Rosenfeld, A.; Taha, H.

1992-06-01

364

Research on Performance Prediction and Maintenance Strategy of Expressway Based on Fuzzy Optimum Theory  

Microsoft Academic Search

Pavement Preventive Maintenance (PPM)technologies is adopted to predict the performance of pavement and select effective strategies on the expressway, the method can enormously extends the service life of pavement and result in lower maintenance costs. This paper describes prediction of highway pavement performance by means of gray system theory, and the gradual solution, which leads to the optimal model, is

Liu Lijun; Zhang Hui

2010-01-01

365

Hanging: nature of ligature material applied and type of hanging according to point of suspension.  

PubMed

One of the most common manners of unnatural death that has been rapidly increasing in Nepal is suicide. The choice of method depends on the accessibility and availability of the means. Therefore suicide by hanging with the ligature material ranging from torn clothing, bed sheet to a shoelace is incorporated. Objective of this study is to find the choice of the type of ligature material used by the victims and the type of hanging found in relation to the point of suspension in both genders. This prospective study was conducted in all cases of death due to hanging (44 cases) during the year January 2007to April 2008 coming for post mortem examination at BPKIHS Dharan Nepal. Nearly half of the hanging victims (21 or 47.72%) used rope for hanging and nearly one third victims (14 or 31.81%) used shawl, rest of victims 4 (9.09%) used sari, 2 (4.54%) victims used either bed sheet or woolen muffler in each and belt was used as ligature by one (2.27%) of the victims. It was observed that in more than half of the cases (25 or 56.81%) hanging was partial (i.e. some body parts were touching the ground). Amongst partial hanging cases, female victims (16 or 64%) outnumbered the male victims (9 or 47.37%).While rest 19 (43.18%) cases were complete hanging (i.e. body was not touching the ground). PMID:23671957

Pradhan, A; Mandal, B K; Tripathi, C B

2012-06-01

366

The effects of repetitive loadings on the shearing strength of a cohesionless soil  

E-print Network

as to style and content by: rman o o ttee ea o Depar ment Nay 1959 CONTENTS I. INTRODUCTION I I a THE PROBLEN ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ III. PRELIMINARY CONSIDERATIONS Elastic and Plastic Properties Effects of Repetitive Loadings on the Shearing Strength... the design of rigid pavements is the amount of detrimental settlement experienced due to plastic strain. Unlike steel, soil is not initially an elastic material, regardless of the stress range. However, it has been shown that certain types of soil...

Dunlap, Donald Dean

1959-01-01

367

A COMPARISON OF TWO THERMAL INSULATION AND STRUCTURAL MATERIALS FOR USE IN TYPE B PACKAGINGS  

SciTech Connect

This paper presents the summary of design features and test results of two Type B Shipping Package prototype configurations comprising different insulating materials developed by the Savannah River National Laboratory (SRNL) for the Department of Energy. The materials evaluated, a closed-cell polyurethane foam and a vacuformed ceramic fiber material, were selected to provide adequate structural protection to the package containment vessel during Normal Conditions of Transport (NCT) and Hypothetical Accident Condition (HAC) events and to provide thermal protection during the HAC fire. Polyurethane foam has been used in shipping package designs for many years because of the stiffness it provides to the structure and because of the thermal protection it provides during fire scenarios. This comparison describes how ceramic fiber material offers an alternative to the polyurethane foam in a specific overpack design. Because of the high operating temperature ({approx}2,300 F) of the ceramic material, it allows for contents with higher heat loads to be shipped than is possible with polyurethane foam. Methods of manufacturing and design considerations using the two materials will be addressed.

Blanton, P.; Eberl, K.

2010-07-16

368

Effects of pavement surface characteristics and textures on skid resistance  

E-print Network

by idealizezl surfaces with hemispherical protrusions; surfaces with crushed aggregates can be characteri. , ed by surfaces with pyramidical protrusions. Low val es of total void areas are related to high values of percent decrease in skid number. Most... 94 97 Texture Depth-Void Area Relationships Introduction. Idealized Surfaces. Tire-Sur. face Contact Conditions Surface with llemispheres. Void area h' ~dh Void area ? texture de th relationWi s Surface with Square Base Pyramids Void area...

Tomita, Hisao

1970-01-01

369

Effects of environment and construction procedures on concrete pavement surfaces  

E-print Network

-2 Determination of Evaporation Rate at the Curing Temperature of 73'F and Wind Conditions of 8-10 mph 97 5-3 Determination of. Evaporation Rate at the Curing Tempera'turn of 73 F and Wind Condi tions of 18-20 mph LIST 0F FIGURES (CONT'D. i Figure Page 5... Effects of. Knvironmenj nnd Construction Proce. 'ure. ; on oncretc Pa'camnt Su face;, (Hay 1971) Ronald 0: to Wrbas, B. S. , Texas AKjj Urivexsity Directed by: Dr. William D. Dedbette The quality of the riding surface is the elemcnj of con- struction...

Wrbas, Ronald Otto

1972-01-01

370

Fish colonization of artificial reefs in a large neotropical reservoir: material type and successional changes.  

PubMed

Artificial reefs have barely been used in Neotropical reservoirs (about five studies in three reservoirs), despite their potential as a fishery management tool to create new habitats and also to understand fish ecology. We experimentally assessed how reef material (ceramic, concrete, and PVC) and time modulated fish colonization of artificial reefs deployed in Itaipu Reservoir, a large reservoir of the mainstem Paraná River, Brazil. Fish richness, abundance, and biomass were significantly greater in the reef treatments than at control sites. Among the experimental reefs, ceramic followed by the concrete treatments were the materials most effectively colonized, harboring the majority of the 13 fish species recorded. Although dependent on material type, many of the regularities of ecological successions were also observed in the artificial reefs, including decelerating increases in species richness, abundance, mean individual size, and species loss rates with time and decelerating decreases of species gain and turnover rates. Species composition also varied with material type and time, together with suites of life history traits: more equilibrium species (i.e., fishes of intermediate size that often exhibit parental care and produce fewer but larger offspring) of the Winemiller-Rose model of fish life histories prevailed in later successional stages. Overall, our study suggests that experimental reefs are a promising tool to understand ecological succession of fish assemblages, particularly in tropical ecosystems given their high species richness and low seasonality. PMID:21516902

Santos, Luciano N; García-Berthou, Emili; Agostinho, Angelo A; Latini, João D

2011-01-01

371

Relating desorption of polycyclic aromatic hydrocarbons from harbour sludges to type of organic material  

NASA Astrophysics Data System (ADS)

For decades, polycyclic aromatic hydrocarbons (PAH) cause great concern as environmental pollutants. Especially river and marine harbour sediments are frequently polluted with PAH derived from surface runoff, fuel and oil spills due to shipping and industrial activities, industrial waste and atmospheric deposition. Harbour sediments contain large amounts of organic carbon and clay minerals and are therefore not easy to remediate and have to be stored in sludge depositories after dredging to maintain sufficient water depth for shipping. The organic contaminants will be adsorbed to particles, leached in association with dissolved organic material or microbially degraded. However, compounds of high molecular weight are very persistent, particularly under anaerobic conditions, thus giving rise to the potential to become desorbed again. PAH adsorb mainly to organic material. It has been shown that components of the organic material with a low polarity and a high hydrophobicity like aliphatic and aromatic components exhibit a high sorption capacity for hydrophobic organic contaminants like PAH. Accordingly, not only the amount but also the type of organic material needs to be determined in order to be able to predict contaminant behaviour. In this study, desorption behaviour of the 16 EPA-PAH in two different harbour sludges from the port of Rotterdam, the Netherlands, has been investigated. The Beerkanaal (BK) site is located relatively close to the North Sea and represents a brackish environment; the Beneden Merwede River (BMR) site originates from a fresh water environment and is close to industrial sites. The samples were placed in dialysis membranes and brought into contact with water for a period of 130 days. At several time intervals, water samples were retrieved for analysis of pH, dissolved organic carbon (DOC) content, electrical conductivity and PAH concentrations. The experiment was conducted at 4 and at 20°C. Although the samples were initially treated with sodium azide to prevent microbial degradation, all samples showed oscillating concentrations of PAH over time pointing to the presence of anaerobic biodegradation. This also had an impact on the temporal development of pH, DOC and electrical conductivity. However, the concentrations of PAH desorbed were very low; for components with a molecular weight higher than pyrene, no desorption was observed at all. On a percentage basis, more PAH desorbed from the BK sample, even though the BMR sample contained an up to ten times higher amount of PAH. In addition, the organic material of the sludges was characterised by C and N elemental and sugar analysis and 13C CPMAS NMR to see how the type of organic material influenced desorption. It was shown that the two sludges did not differ significantly in the amount but more in the type of organic material. The BK sample contained organic material which was more degraded than the BMR sample. By combining desorption behaviour with organic material characterisation, we will show how the type of organic material influences desorption of PAH from the sediments.

Heister, K.; Pols, S.; Loch, J. P. G.; Bosma, T.

2009-04-01

372

Cherenkov-type terahertz emission from ultrafast magnetization in a slab of magnetooptic material  

NASA Astrophysics Data System (ADS)

We develop a theory of terahertz emission from a slab of a magnetooptic material traversed by a circularly polarized femtosecond laser pulse. The Cherenkov-type radiation is generated by a moving region of ultrafast magnetization optically induced in the slab via the inverse Faraday effect. A prism is used to couple the radiation from the slab to free space. Our theory accounts for transient effects at the slab boundaries and shows their significance for the interpretation of the terahertz waveform emitted from the slab. The theory predicts detectability of the radiation generated by a mJ-level laser pulse in a terbium gallium garnet slab covered with a sapphire prism.

Sychugin, S. A.; Anisimov, E. A.; Bakunov, M. I.

2015-03-01

373

Dynamic response of guardrail systems encased in pavement mow strips  

E-print Network

Cases 23 . . . . 24 27 29 32 34 . . . . . 35 36 37 . . . 37 38 39 FIGURE Page 26 Second Set of Asphalt Mow Strip Test Cases . . . 40 27 Asphalt Mow Strip Bogie Test with Rubber Mat. . . 41 28 Accelerations of Bogie for First Set... Strip Wood Post Tests. . . . . . . . . . 44 33 Deformed Steel Post Surrounded by Rubber Mat after Bogie Impact. . . , . . . . . . . . 45 Concrete Mow Strip Test Installation. 46 35 Posts Embedded in a Concrete Mow Strip: (a) Steel Post; (b) Wood Post...

Seckinger, Nathaniel Ryan

2002-01-01

374

Development of design criteria pertaining to signing, pavement markings, and geometric cross-section for improved two-lane section (Texas Super 2)  

E-print Network

The purpose of this research was to establish the optimum driver information strategy regarding Super 2 passing lane sections in Texas. A Driver Survey and a Before and After Study examining proposed skip stripe pavement marking, signing...

Heard, Barry Don

2001-01-01

375

Impact of Curing Methods on Curling of Concrete Pavements  

E-print Network

-tightness · Improve abrasion resistance cement grain #12;Why is curing important? Proper curing will: · Reduce permeability · Improve strength · Improve water-tightness · Improve abrasion resistance cement grain #12;Why-tightness · Improve abrasion resistance cement graincapillary pores #12;What is the goal of this project? #12;What

376

Life-Cycle Assessment of Highway Pavement Alternatives in Aspects of Economic, Environmental, and Social Performance  

E-print Network

, hazardous waste, toxic releases, water withdrawals, and transportation movements. The analysis results indicate that CRCP be the most cost-efficient and sustainable choice among the selected rigid pavement alternatives as it requires the lowest life...

Mao, Zhuting

2012-10-19

377

A one-pot reaction to synthesize two types of fluorescent materials containing benzothiazolyl moiety  

NASA Astrophysics Data System (ADS)

Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl)coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, 1H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.

Yu, Tianzhi; Zhang, Chengcheng; Zhao, Yuling; Chai, Haifang; Fan, Duowang; Ma, Ying; Yao, Shanglei; Li, Wentao

2013-05-01

378

Satellite Material Type and Phase Function Determination in Support of Orbital Debris Size Estimation  

NASA Technical Reports Server (NTRS)

In performing debris surveys of deep-space orbital regions, the considerable volume of the area to be surveyed and the increased orbital altitude suggest optical telescopes as the most efficient survey instruments; but to proceed this way, methodologies for debris object size estimation using only optical tracking and photometric information are needed. Basic photometry theory indicates that size estimation should be possible if satellite albedo and shape are known. One method for estimating albedo is to try to determine the object's material type photometrically, as one can determine the albedos of common satellite materials in the laboratory. Examination of laboratory filter photometry (using Johnson BVRI filters) on a set of satellite material samples indicates that most material types can be separated at the 1-sigma level via B-R versus R-I color differences with a relatively small amount of required resampling, and objects that remain ambiguous can be resolved by B-R versus B-V color differences and solar radiation pressure differences. To estimate shape, a technique advanced by Hall et al. [1], based on phase-brightness density curves and not requiring any a priori knowledge of attitude, has been modified slightly to try to make it more resistant to the specular characteristics of different materials and to reduce the number of samples necessary to make robust shape determinations. Working from a gallery of idealized debris shapes, the modified technique identifies most shapes within this gallery correctly, also with a relatively small amount of resampling. These results are, of course, based on relatively small laboratory investigations and simulated data, and expanded laboratory experimentation and further investigation with in situ survey measurements will be required in order to assess their actual efficacy under survey conditions; but these techniques show sufficient promise to justify this next level of analysis.

Hejduk, M. D.; Cowardin, H. M.; Stansbery, Eugene G.

2012-01-01

379

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

PubMed

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 ?m) 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

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

2012-03-01

380

9 CFR 354.247 - Table showing types of materials.  

Code of Federal Regulations, 2011 CFR

...354.247 Section 354.247 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ...A Conveyor track A A A Shackles A A Shackle chain A A A Eviscerating pans A A A Inspection...

2011-01-01

381

9 CFR 354.247 - Table showing types of materials.  

Code of Federal Regulations, 2013 CFR

...354.247 Section 354.247 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ...A Conveyor track A A A Shackles A A Shackle chain A A A Eviscerating pans A A A Inspection...

2013-01-01

382

9 CFR 354.247 - Table showing types of materials.  

Code of Federal Regulations, 2014 CFR

...354.247 Section 354.247 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ...A Conveyor track A A A Shackles A A Shackle chain A A A Eviscerating pans A A A Inspection...

2014-01-01

383

9 CFR 354.247 - Table showing types of materials.  

Code of Federal Regulations, 2010 CFR

...354.247 Section 354.247 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ...A Conveyor track A A A Shackles A A Shackle chain A A A Eviscerating pans A A A Inspection...

2010-01-01

384

An evaluation of the flexible pavement design system FPS19  

E-print Network

. . . . . . 31 6. Summary of Granular Base Thickness vs Temp. Constant . . . . . . . . . . . . . . . . 33 7. Summary of Granular Base Thickness vs Subgrade Modulus . . . . . . . . . . . 36 8. Summary of Granular Base Thickness vs Base Modulus.... Summary of Asph. Stab. Base Thickness vs Reliability . . . . . . 46 48 14. Summary of Asph. Stab. Base Thickness vs Temp. Constant . . . . . . . . . . . 50 15. Summary of Asph. Stab. Base Thickness vs Subgrade Modulus . . . . . . . 52 16. Summary...

Carmona, Gerardo M

1998-01-01

385

Measurement of physical characteristics of materials by ultrasonic methods  

DOEpatents

A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc. 14 figs.

Lu, W.Y.; Min, S.

1998-09-08

386

Measurement of physical characteristics of materials by ultrasonic methods  

DOEpatents

A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc.

Lu, Wei-yang (Pleasanton, CA); Min, Shermann (Livermore, CA)

1998-01-01

387

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...

388

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...

389

X-ray inspection of composite materials for aircraft structures using detectors of Medipix type  

NASA Astrophysics Data System (ADS)

This work presents an overview of promising X-ray imaging techniques employed for non-destructive defectoscopy inspections of composite materials intended for the Aircraft industry. The major emphasis is placed on non-tomographic imaging techniques which do not require demanding spatial and time measurement conditions. Imaging methods for defects visualisation, delamination detection and porosity measurement of various composite materials such as carbon fibre reinforced polymers and honeycomb sendwiches are proposed. We make use of the new large area WidePix X-ray imaging camera assembled from up to 100 edgeless Medipix type detectors which is highly suitable for this type of measurements.

Jandejsek, I.; Jakubek, J.; Jakubek, M.; Prucha, P.; Krejci, F.; Soukup, P.; Turecek, D.; Vavrik, D.; Zemlicka, J.

2014-05-01

390

Toward an Improved Model of Asphalt Binder Oxidation in Pavements  

E-print Network

Transportation Institute (TTI). Finally, I would like to thank my parents, Nopadol and Kanokpun, who are always there for me no matter what the situation. Being your son is the best thing that I could ever wish for. I am also in great debt to my sister..., Arpaporn, who has taken on the responsibilities of serving our parents in my absence. All the support from these precious people made my study and achievement possible. I appreciate all of them from the deepest feelings of my heart. vii NOMENCLATURE...

Prapaitrakul, Nikornpon

2011-02-22

391

Influence of Three Permeable Pavement Surfaces on Nitrogen Treatment  

EPA Science Inventory

Nitrogen is a stressor of concern in many nutrient sensitive watersheds often associated with algal blooms and resulting fish kills. Communities are increasingly installing green infrastructure stormwater control measures (SCMs) to reduce pollutant loads associated with stormwat...

392

BEHAVIOR AND PERFORMANCE OF UTW ON THIN ASPHALT PAVEMENT  

Microsoft Academic Search

During the 1999 spring, two sections of ultra-thin whitetopping (UTW) were built in an urban street in São Paulo City over a thin 45 mm asphalt layer. The UTW was constructed at a bus stop within the University campus, defining two panels of squared 0.6 and 1.0 m and 95 mm slabs. A high strength concrete was applied and the

José Balbo; Deividi Pereira; Andréa Severi

393

Monitoring pavement response and performance using in-situ instrumentation  

SciTech Connect

The purpose of this paper is to present the effectiveness of in-situ instrumentation on diagnosing the pavement layer conditions under full-scale accelerated traffic loading. The test section is an in-service pavement (US281) in Jacksboro, Texas. Multi-Depth Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometer (FWD) tests. Four different FWD loads of 25, 40, 52, and 67 kN were applied in close proximity to the MDDs at various traffic loading intervals to determine pavement conditions. It was found that the majority of rutting occurred in the newly recycled asphalt mix. The aged ({gt}40 years) underlying base and subgrade layers contributed less than 30% to overall rutting. Only the top recycled Asphalt layer underwent notable deterioration due to traffic loading. Up to 1.5 million axle repetitions, the test pad responded to FWD load almost linearly, not only over the whole pavement system but also within individual layers. However, under higher FWD loads, the percentage of total deflection contributed by the subgrade increased.

Chen, D.H.; Bilyeu, J.; Hugo, F.

1999-07-01

394

Influence of weight and type of planting material on fruit quality and its heterogeneity in pineapple [Ananas comosus (L.) Merrill  

PubMed Central

Cultural practices can affect the quality of pineapple fruits and its variation. The objectives of this study were to investigate (a) effects of weight class and type of planting material on fruit quality, heterogeneity in quality and proportion and yield of fruits meeting European export standards, and (b) the improvement in quality, proportion and yield of fruits meeting export standards when flowering was induced at optimum time. Experiments were conducted in Benin with cvs Sugarloaf (a Perola type) and Smooth Cayenne. In cv. Sugarloaf, experimental factors were weight class of planting material (light, mixed, heavy) and time of flowering induction (farmers', optimum) (Experiment 1). In cv. Smooth Cayenne an additional experimental factor was the type of planting material (hapas, ground suckers, a mixture of the two) (Experiment 2). Fruits from heavy planting material had higher infructescence and fruit weights, longer infructescences, shorter crowns, and smaller crown: infructescence length than fruits from light planting material. The type of planting material in Experiment 2 did not significantly affect fruit quality except crown length: fruits from hapas had shorter crowns than those from ground suckers. Crops from heavy planting material had a higher proportion and yield of fruits meeting export standards than those from other weight classes in Experiment 1 only; also the type of planting material in Experiment 2 did not affect these variates. Heterogeneity in fruit quality was usually not reduced by selecting only light or heavy planting material instead of mixing weights; incidentally the coefficient of variation was significantly reduced in fruits from heavy slips only. Heterogeneity was also not reduced by not mixing hapas and ground suckers. Flowering induction at optimum time increased the proportion and yield of fruits meeting export standards in fruits from light and mixed slip weights and in those from the mixture of heavy hapas plus ground suckers. PMID:25653659

Fassinou Hotegni, V. Nicodème; Lommen, Willemien J. M.; Agbossou, Euloge K.; Struik, Paul C.

2015-01-01

395

Psychological distress by type of fertility barrier  

Microsoft Academic Search

BACKGROUND: We examined fertility-specific distress (FSD) and general distress by type of fertility barrier (FB). METHODS: In a random sample telephone survey, 580 US women reported their fertility intentions and histories. Six groups of women were identified: (i) no FBs, (ii) infertile with intent, (iii) infertile without intent, (iv) other fertility problems, (v) miscarriages and (vi) situational barriers. Multiple regression

Mary Casey Jacob; J. McQuillan; A. L. Greil

2006-01-01

396

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. ...

397

Asphalt Mechanics, a Key Tool for Improved Pavement Performance Predictions  

Microsoft Academic Search

Pavement design has relied for a very long time on simplified mechanistic methods and experience. The need for long life maintenance\\u000a structures, the use of new, costly, materials with enhanced characteristics, the need to spend the maintenance euro as effective\\u000a as possible, the need to quantify risks etc, have given a boost to a renewed interest in the characterization and

A. A. A. Molenaar

398

Probe-type of superconductivity by impurity in materials with short coherence length: the s-wave and ?-wave phases study  

NASA Astrophysics Data System (ADS)

The effects of a single non-magnetic impurity on superconducting states in the Penson–Kolb–Hubbard model have been analyzed. The investigations have been performed within the Hartree–Fock mean field approximation in two steps: (i) the homogeneous system is analysed using the Bogoliubov transformation, whereas (ii) the inhomogeneous system is investigated by self-consistent Bogoliubov-de Gennes equations (with the exact diagonalization and the kernel polynomial method). We analysed both signs of the pair hopping, which correspond to s-wave and ?-wave superconductivity. Our results show that an enhancement of the local superconducting gap at the impurity-site occurs for both cases. We obtained that Cooper pairs are scattered (at the impurity site) into the states which are from the neighborhoods of the states, which are commensurate ones with the crystal lattice. Additionally, in the ?-phase there are peaks in the local-energy gap (in momentum space), which are connected with long-range oscillations in the spatial distribution of the energy gap, superconducting order parameter (SOP), as well as effective pairing potential. Our results can be contrasted with the experiment and predicts how to experimentally differentiate these two different symmetries of SOP by the scanning tunneling microscopy technique.

Ptok, Andrzej; Jerzy Kapcia, Konrad

2015-04-01

399

Development of high-toughness low-viscosity nano-molecular resins for reinforcing pothole patching materials  

NASA Astrophysics Data System (ADS)

As the nation's asphalt pavements age and deteriorate, the need for corrective measures to restore safety and rideability increases. The potholes and alligator cracks in the asphalt pavement of our country's roadways have become an annoying part of our daily life and no innovative technologies are available to improve the safety of US drivers, reduce the cost of road maintenance. We have identified a polymeric material, dicyclopentadiene (DCPD) resin, which can be cured by Grubb's catalyst and other commercially available catalysts to become an ultratough material with all the desired properties for pothole repair. We have characterized DCPD infiltration characteristics using non-destructive CT scan, and the mechanical properties using indirect tensile test under hot, cold or wet conditions. The preliminary results show that DCPD is a promising material for applications in reinforced pothole patching materials.

Yuan, Wei; Yuan, Matt; Zou, Linhua; Yang, Jenn-Ming; Ju, Woody; Kao, Wei; Carlson, Larry; Edgecombe, Brian; Stephen, Tony; Villacorta, Ricardo; Solamon, Ray

2011-04-01

400

Thermal Output of WK-Type Strain Gauges on Various Materials at Cryogenic and Elevated Temperatures  

NASA Technical Reports Server (NTRS)

Strain gage apparent strain (thermal output) is one of the largest sources of error associated with the measurement of strain when temperatures and mechanical loads are varied. In this paper, experimentally determined apparent strains of WK-type strain gages, installed on both metallic and composite-laminate materials of various lay-ups and resin systems for temperatures ranging from -450 F to 230 F are presented. For the composite materials apparent strain in both the 0 ply orientation angle and the 90 ply orientation angle were measured. Metal specimens tested included: aluminum-lithium alloy (Al-LI 2195-T87), aluminum alloy (Al 2219-T87), and titanium alloy. Composite materials tested include: graphite-toughened-epoxy (IM7/997- 2), graphite-bismaleimide (IM7/5260), and graphite-K3 (IM7/K3B). The experimentally determined apparent strain data are curve fit with a fourth-order polynomial for each of the materials studied. The apparent strain data and the polynomials that are fit to the data are compared with those produced by the strain gage manufacturer, and the results and comparisons are presented. Unacceptably high errors between the manufacture's data and the experimentally determined data were observed (especially at temperatures below - 270-F).

Kowalkowski, Matthew K.; Rivers, H. Kevin; Smith, Russell W.

1998-01-01

401

Engineering of fluorescent emission of silk fibroin composite materials by material assembly.  

PubMed

This novel materials assembly technology endows the designated materials with additional/enhanced performance by fixing "functional components" into the materials. Such functional components are molecularly recognized and accommodated by the designated materials. In this regard, two-photon fluorescence (TPF) organic molecules and CdTe quantum dots (QDs) are adopted as functional components to functionalize silk fibers and films. TPF organic molecules, such as, 2,7-bis[2-(4-nitrophenyl) ethenyl]-9,9-dibutylfluorene (NM), exhibit TPF emission quenching because of the molecular stacking that leads to aggregation in the solid form. The specific recognition between -NO2 in the annealed fluorescent molecules and the -NH groups in the silk fibroin molecules decouples the aggregated molecules. This gives rise to a significant increase in the TPF quantum yields of the silk fibers. Similarly, as another type of functional components, CdTe quantum dots (QDs) with different sizes were also adopted in the silk functionalization method. Compared to QDs in solution the fluorescence properties of functionalized silk materials display a long stability at room temperature. As the functional materials are well dispersed at high quantum yields in the biocompatible silk a TPF microscope can be used to pursue 3D high-resolution imaging in real time of the TPF-silk scaffold. PMID:25270616

Lin, Naibo; Meng, Zhaohui; Toh, Guoyang William; Zhen, Yang; Diao, Yingying; Xu, Hongyao; Liu, Xiang Yang

2015-03-01

402

Possibility of Shear Type Fracture in Viscoplastic Material under Confining Pressures  

NASA Astrophysics Data System (ADS)

Transition from opening-mode wing crack growth to shear type fracture has been investigated by conducting triaxial compression tests under confining pressures, using epoxy resin cylindrical specimens. The epoxy resin used exhibited viscoplastic deformation characteristics under confining pressures, which is expected to simulate the nonlinear deformation observed commonly for rocks at great depths and to provide useful insight in understanding of the fracture transition in rocks. Under the range of confining pressures, 10 MPa-30 MPa, an array of opening-mode wing cracks were initiated from a preexisting inclined penny-shaped crack, as the axial stress was increased. Only the extension of a wing crack was observed to take place under no confining pressure condition. It was shown that the growth of the wing cracks were suppressed when higher confining pressures were applied and shear type fracture consisting of several wing cracks was induced as the deformation progressed. The experimental observation suggests the possibility of occurrence of shear type fracture in such a homogeneous material under higher confining pressures, and the mechanical interaction between cracks plays a crucial role in the generation of shear type fracture rather than the inhomogeneity of rocks.

Yamaguchi, H.; Sakaguchi, K.; Sato, K.; Matsuki, K.; Hashida, T.

2008-02-01

403

EVIDENCE FOR ASYMMETRIC DISTRIBUTION OF CIRCUMSTELLAR MATERIAL AROUND TYPE Ia SUPERNOVAE  

SciTech Connect

We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v{sub neb}), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v{sub neb}, with generally stronger absorption for SNe Ia with v{sub neb} {>=} 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

Foerster, Francisco; Gonzalez-Gaitan, Santiago; Anderson, Joseph; Marchi, Sebastian; Gutierrez, Claudia; Hamuy, Mario; Cartier, Regis [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Pignata, Giuliano [Departamento Ciencias Fisicas, Universidad Andres Bello, Av. Republica 252, Santiago (Chile)

2012-08-01

404

Myosins XI-K, XI-1, and XI-2 are required for development of pavement cells, trichomes, and stigmatic papillae in Arabidopsis  

PubMed Central

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

2012-01-01

405

DEFLECTIONS MEASURED ON EXPERIMENTAL ULTRA-THIN WHITETOPPING PAVEMENTS  

Microsoft Academic Search

In the spring of 1998, the Federal Highway Administration (FHWA) and the American Concrete Pavement Association (ACPA) jointly constructed eight full-scale lanes of ultra-thin whitetopping (UTW) over existing hot mix asphalt (HMA) pavements. These sections were placed at the FHWA's Pavement Test Facility, located at the Turner-Fairbank Highway Research Center in McLean, Virginia. The experiment employed various combinations of thickness,

Xicheng Qi; James A. Sherwood; FHWA Terry Mitchell

406

Magnetic and Electrical Characteristics of Cobalt-Based Amorphous Materials and Comparison to a Permalloy Type Polycrystalline Material  

NASA Technical Reports Server (NTRS)

Magnetic component designers are always looking for improved soft magnetic core materials to increase the efficiency, temperature rating and power density of transformers, motors, generators and alternators, and energy density of inductors. In this paper, we report on the experimental investigation of commercially available cobalt-based amorphous alloys which, in their processing, were subjected to two different types of magnetic field anneals: A longitudinal magnetic field anneal or a transverse magnetic field anneal. The longitudinal field annealed material investigated was Metglas 2714A. The electrical and magnetic characteristics of this material were investigated over the frequency range of 1 to 200 kHz and temperature range of 23 to 150 C for both sine and square wave voltage excitation. The specific core loss was lower for the square than the sine wave voltage excitation for the same maximum flux density, frequency and temperature. The transverse magnetic field annealed core materials include Metglas 2714AF and Vacuumschmelze 6025F. These two materials were experimentally characterized over the frequency range of 10 to 200 kHz for sine wave voltage excitation and 23 C only. A comparison of the 2174A to 2714AF found that 2714AF always had lower specific core loss than 2714A for any given magnetic flux density and frequency and the ratio of specific core loss of 2714A to 2714AF was dependent on both magnetic flux density and frequency. A comparison was also made of the 2714A, 2714AF, and 6025F materials to two different tape thicknesses of the polycrystalline Supermalloy material and the results show that 2714AF and 6025F have the lowest specific core loss at 100 kHz over the magnetic flux density range of 0.1 to 0.4 Tesla.

Wieserman, William R.; Schwarze, Gene E.; Niedra, Janis M.

2005-01-01

407

Determination of bisphenol-type endocrine disrupting compounds in food-contact recycled-paper materials by focused ultrasonic solid-liquid extraction and ultra performance liquid chromatography-high resolution mass spectrometry.  

PubMed

Focused ultrasonic solid-liquid extraction (FUSLE) and reverse-phase ultra performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) was applied to the determination of bisphenol-type endocrine disrupting compounds (EDCs) in food-contact recycled-paper materials. Recycled paper is a potential source of EDCs. Bisphenol A (BPA), bisphenol F (BPF) and their derivatives bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used for the production of epoxy resins employed in the formulation of printing inks. The FUSLE of bisphenol-type EDCs from packaging is reported for the first time. First, different extraction solvents were studied and methanol was selected. Then, the main FUSLE factors affecting the extraction efficiency (solvent volume, extraction time and ultrasonic irradiation power) were studied by means of a central composite design. The FUSLE conditions selected for further experiments were 20 ml of methanol at ultrasonic amplitude of 100% for 5s. Finally, the number of extraction cycles necessary for complete extraction was established in two. The analysis of the FUSLE extracts was carried out by UPLC-Q-TOF-MS with electrospray ionization and the determination of the four analytes took place in only 4 min. The FUSLE and UPLC-ESI-QTOF-MS method was validated and applied to the analysis of different food-contact recycled-paper-based materials and packaging. The proposed method provided recoveries from 72% to 97%, repeatability and intermediate precision under 9% and 14%, respectively, and detection limits of 0.33, 0.16, 0.65 and 0.40 ?g/g for BPA, BPF, BADGE and BFDGE, respectively. The analysis of paper and cardboard samples confirmed the presence of EDCs in these packaging. PMID:22967537

Pérez-Palacios, David; Fernández-Recio, Miguel Ángel; Moreta, Cristina; Tena, María Teresa

2012-09-15

408

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...

409

Association between moderate-to-severe diarrhea in young children in the global enteric multicenter study (GEMS) and types of handwashing materials used by caretakers in Mirzapur, Bangladesh.  

PubMed

Handwashing practices among caretakers of case and control children < 5 years of age enrolled in the Global Enteric Multicenter Study in Mirzapur, Bangladesh were characterized and analyzed for association with moderate-to-severe diarrhea. Soap or detergent ownership was common, yet 48% of case and 47.7% of control caretakers also kept ashes for handwashing, including 36.8% of the wealthiest households. Soap, detergent, and ash were used for multiple hygiene purposes and were kept together at handwashing areas. Caretakers preferred soap for handwashing, but frequently relied on ash, or a detergent/ash mixture, as a low-cost alternative. Moderate-to-severe diarrhea was equally likely for children of caretakers who kept soap versus those who kept ash (matched OR = 0.91; 0.62-1.32). Contact with ash and water reduced concentrations of bacterial enteropathogens, without mechanical scrubbing. Thus, washing hands with ash is a prevalent behavior in Mirzapur and may help diminish transmission of diarrheal pathogens to children. PMID:24778193

Baker, Kelly K; Dil Farzana, Fahmida; Ferdous, Farzana; Ahmed, Shahnawaz; Kumar Das, Sumon; Faruque, A S G; Nasrin, Dilruba; Kotloff, Karen L; Nataro, James P; Kolappaswamy, Krishnan; Levine, Myron M

2014-07-01

410

Association between Moderate-to-Severe Diarrhea in Young Children in the Global Enteric Multicenter Study (GEMS) and Types of Handwashing Materials Used by Caretakers in Mirzapur, Bangladesh  

PubMed Central

Handwashing practices among caretakers of case and control children < 5 years of age enrolled in the Global Enteric Multicenter Study in Mirzapur, Bangladesh were characterized and analyzed for association with moderate-to-severe diarrhea. Soap or detergent ownership was common, yet 48% of case and 47.7% of control caretakers also kept ashes for handwashing, including 36.8% of the wealthiest households. Soap, detergent, and ash were used for multiple hygiene purposes and were kept together at handwashing areas. Caretakers preferred soap for handwashing, but frequently relied on ash, or a detergent/ash mixture, as a low-cost alternative. Moderate-to-severe diarrhea was equally likely for children of caretakers who kept soap versus those who kept ash (matched OR = 0.91; 0.62–1.32). Contact with ash and water reduced concentrations of bacterial enteropathogens, without mechanical scrubbing. Thus, washing hands with ash is a prevalent behavior in Mirzapur and may help diminish transmission of diarrheal pathogens to children. PMID:24778193

Baker, Kelly K.; Dil Farzana, Fahmida; Ferdous, Farzana; Ahmed, Shahnawaz; Kumar Das, Sumon; Faruque, A. S. G.; Nasrin, Dilruba; Kotloff, Karen L.; Nataro, James P.; Kolappaswamy, Krishnan; Levine, Myron M.

2014-01-01

411

Materials data handbook: Stainless steel type 301  

NASA Technical Reports Server (NTRS)

A summary of the materials property information for stainless steel type 301 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and bonding is developed.

Muraca, R. F.; Whittick, J. S.

1972-01-01

412

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...

413

Pavement rehabilitation and funds allocation for a transportation network  

E-print Network

Continuously reinforced concrete pavement Jointed reinforced concrete pavement Jointed plain concrete pavement EP-4 EP-5 EP-6 EP-7 EP-8 EP-9 EP-10 Thick asphaltic concrete pavement (greater than 5 1/2" of hot-mixed asphaltic layers) Intermediate... condition of a h1ghway segment. AVU = Adjusted v 1sual defect utility. SIU = Serviceability index utility. SKU = Sk1 d number utility SCU = Structural Capac1ty ut1lity. al, a2, a3, a4 = Weighting factors. 1 1 (ADTF)(KEF) 2 3 4 ADTF = Average daily...

Stein, Alvaro

1985-01-01

414

Modeling ozone removal to indoor materials, including the effects of porosity, pore diameter, and thickness.  

PubMed

We develop an ozone transport and reaction model to determine reaction probabilities and assess the importance of physical properties such as porosity, pore diameter, and material thickness on reactive uptake of ozone to five materials. The one-dimensional model accounts for molecular diffusion from bulk air to the air-material interface, reaction at the interface, and diffusive transport and reaction through material pore volumes. Material-ozone reaction probabilities that account for internal transport and internal pore area, ?ipa, are determined by a minimization of residuals between predicted and experimentally derived ozone concentrations. Values of ?ipa are generally less than effective reaction probabilities (?eff) determined previously, likely because of the inclusion of diffusion into substrates and reaction with internal surface area (rather than the use of the horizontally projected external material areas). Estimates of ?ipa average 1 × 10(-7), 2 × 10(-7), 4 × 10(-5), 2 × 10(-5), and 4 × 10(-7) for two types of cellulose paper, pervious pavement, Portland cement concrete, and an activated carbon cloth, respectively. The transport and reaction model developed here accounts for observed differences in ozone removal to varying thicknesses of the cellulose paper, and estimates a near constant ?ipa as material thickness increases from 0.02 to 0.16 cm. PMID:25748309

Gall, Elliott T; Siegel, Jeffrey A; Corsi, Richard L

2015-04-01

415

The Effect of Personality Type on Team Performance in Engineering Materials Term Projects  

NSDL National Science Digital Library

Most of long-term engineering class projects require teamwork. Often, conducting projects increase the quality of classroom life and facilitate student learning. Sometimes, team projects hinder student learning and create disharmony and dissatisfaction with classroom life. In many cases, the mixture of each individuals personality determines team dynamics. The Introduction to Engineering Materials course for junior level students encompasses a semester-long term project, which heavily requires teamwork. The term project should focus on a component of existing manufactured products and show why a particular material is used for a particular application. The experiments chosen should prove or disprove this. Each team will chose a topic, determine how to evaluate that topic, devise relevant experiments, evaluate the results of these experiments and formulate a conclusion. Finally, the students will present their results to the class at the end of the semester. The goal of this study is to see how the team performance can be affected by each individual students personality type in the term projects of the engineering material course. The personality test used in this study was the DISC test, which is the oldest, most validated, and reliable personality assessment tool. DISC stands for Dominance, Influence, Steadiness, and Conscientiousness, which are the four dimensions in the personality characteristics. For the term project, six teams were formulated. The instructor assigned four or five students to a team. Students with similar personality types were assigned to work with each other in three of the teams. The other three teams have students with well-mixed dimensions in their personality characteristics. This paper presents the effectiveness of using student personality on team building for the semester-long team projects. Overall student experience and lessons learned in organizing such a project are also discussed.

Jang, Jaesoon

416

Reuse of polyethylene waste in road construction.  

PubMed

The cost of construction of flexible pavements depends on thickness of the pavement layers. The thickness of pavement mainly depends on the strength of the subgrade. By suitable improvement to the strength of the subgrade, considerable saving in the scarce resources and economy can be achieved. Because of their lightweight, easy handling, non-breakable and corrosion free nature, polyethylene have surpassed all other materials in utility. But polyethylene waste has been a matter of concern to environmentalists as it is non-biodegradable. In this investigation, an attempt has been made to study the improvement of California Bearing Ratio (CBR) value of soils stabilized with waste polyethylene bags. This alternative material is mixed in different proportions to the gravel and clay to determine the improvement ofCBR value. Use of the waste polyethylene bags observed to have a significant impact on the strength and economy in pavement construction, when these are available locally in large quantities. PMID:18472564

Raju, S S S V Gopala; Murali, M; Rengaraju, V R

2007-01-01

417

High performance P-type thermoelectric materials and methods of preparation  

NASA Technical Reports Server (NTRS)

The present invention is embodied in high performance p-type thermoelectric materials having enhanced thermoelectric properties and the methods of preparing such materials. In one aspect of the invention, p-type semiconductors of formula Zn.sub.4-x A.sub.x Sb.sub.3-y B.sub.y wherein 0.ltoreq.x.ltoreq.4, A is a transition metal, B is a pnicogen, and 0.ltoreq.y.ltoreq.3 are formed for use in manufacturing thermoelectric devices with substantially enhanced operating characteristics and improved efficiency. Two methods of preparing p-type Zn.sub.4 Sb.sub.3 and related alloys of the present invention include a crystal growth method and a powder metallurgy method.

Caillat, Thierry (Inventor); Borshchevsky, Alexander (Inventor); Fleurial, Jean-Pierre (Inventor)

2002-01-01

418

POROUS PAVEMENT PHASE I DESIGN AND OPERATIONAL CRITERIA (EPA/600/2-80/135)  

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 ...

419

Development and evaluation of thermoplastic street maintenance material  

NASA Technical Reports Server (NTRS)

An all-weather permanent street patching material was investigated for flexible and rigid pavements. The economic, operational, and material requirements are discussed along with the results of field tests with various mixtures of EVA resins and asphalt. Cost analyses for thermoplastic patching methods are included.

Siemens, W. D.

1973-01-01

420

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

PubMed

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

Starke, P; Göbel, P; Coldewey, W G

2011-01-01

421

High temperature sensing of thermal barrier materials by luminescence  

NASA Astrophysics Data System (ADS)

The basis for a number of concepts for in situ monitoring of thermal barrier coating heath and temperature using non-contact luminescence techniques is described. Restrictions imposed by phase compatibility and the optical properties of the coating materials are discussed as guidelines for the selection of rare-earth ions as chromophore dopants in these sensors. Extensive studies of type and concentration of rare-earth doping lead to the selection of Eu-doped materials as the preferred material for temperature sensing. Sensor layers, consisting of 1 atomic percent europia-doped yttria stabilized zirconia were deposited and exposed to high heat flux conditions similar to those seen today's turbine environments and were shown to be capable of measuring temperature at different depths within the coating.

Gentleman, Molly Maureen

422

Using finite element structural analysis to study retroreflective raised pavement markers  

E-print Network

will be examined and additional tests be recommended based on the tire-marker impact analysis. The researcher found that the critical compressive stress is produced at the top edges of the markers on both types of pavement, while the patterns of critical tensile...

Tong, Jiaxin

2009-06-02