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1

Evaluation of flexible pavement performance life in Florida. Final research report, October 1993--June 1998  

SciTech Connect

The pavement performance life provides information on how long a particular pavement type will typically last before it needs rehabilitation. This study presents the research effort to estimate the average flexible pavement performance life in Florida. Two data files of Pavement Condition Survey (PCS) and Work Program Administration (WPA) were used for this study. SAS programs were applied to analyze and manipulate these two data files. The pavement performance condition curves were developed for a large sample size of pavement sections based on the polynomial model. The average pavement performance lives were evaluated for each pavement group based on the performance curves. The results of the evaluation showed that the primary system had longer average performance life than the interstate system. Generally, the polynomial model performed well in fitting the data. The pavement performance curve indicates that if M and R are performed while the pavement is still in the `slow rate of deterioration` phase, life cycle cost may be reduced.

Ping, W.V.; He, Y.

1998-06-01

2

PORTLAND CEMENT CONCRETE PAVEMENT FOR FLEXIBLE OVER RIGID COMPOSITE PAVEMENTS (Tollway)  

E-print Network

PORTLAND CEMENT CONCRETE PAVEMENT FOR FLEXIBLE OVER RIGID COMPOSITE PAVEMENTS (Tollway) Effective portland cement concrete for special applications to composite pavements as shown and described. Developing concrete mix design(s) that meets the performance requirements for the intended pavement; 4

3

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

4

1 INTRODUCTION A typical flexible pavement system includes four  

E-print Network

1 INTRODUCTION A typical flexible pavement system includes four distinct layers: asphalt concrete course in order to reduce costs or to minimize capil- lary action under the pavement. Figure 1: Cross-section of flexible pavement system (Muench 2006) Pavement distress may occur due to either traffic or environmental

Zornberg, Jorge G.

5

Evaluation of tire pressure, tire construction, axle configuration, and axle load on flexible pavement performance  

E-print Network

loading among axles, and high tire pressures. The tire is represented as a uniformly loaded circular area with contact pressure assumed as 9OX, of inflation pressure. A modified Chevron N-layer model was used to calculate pavement stresses and strains... loading among axles, and high tire pressures. The tire is represented as a uniformly loaded circular area with contact pressure assumed as 9OX, of inflation pressure. A modified Chevron N-layer model was used to calculate pavement stresses and strains...

Jamy, Ahmad Najeeb

2012-06-07

6

Analysis and design optimization of flexible pavement  

SciTech Connect

A project-level optimization approach was developed to minimize total pavement cost within an analysis period. Using this approach, the designer is able to select the optimum initial pavement thickness, overlay thickness, and overlay timing. The model in this approach is capable of predicting both pavement performance and condition in terms of roughness, fatigue cracking, and rutting. The developed model combines the American Association of State Highway and Transportation Officials (AASHTO) design procedure and the mechanistic multilayer elastic solution. The Optimization for Pavement Analysis (OPA) computer program was developed using the prescribed approach. The OPA program incorporates the AASHTO equations, the multilayer elastic system ELSYM5 model, and the nonlinear dynamic programming optimization technique. The program is PC-based and can run in either a Windows 3.1 or a Windows 95 environment. Using the OPA program, a typical pavement section was analyzed under different traffic volumes and material properties. The optimum design strategy that produces the minimum total pavement cost in each case was determined. The initial construction cost, overlay cost, highway user cost, and total pavement cost were also calculated. The methodology developed during this research should lead to more cost-effective pavements for agencies adopting the recommended analysis methods.

Mamlouk, M.S.; Zaniewski, J.P.; He, W.

2000-04-01

7

Evaluation of base widening methods on flexible pavements in Wyoming  

NASA Astrophysics Data System (ADS)

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

Offei, Edward

8

Effects of overlay designs on reliability of flexible pavements  

Microsoft Academic Search

Management of flexible pavements requires timely application of preventive maintenance and rehabilitation actions such as overlays. These actions are an integral part of a design strategy that minimises the use of recourses over the pavement's life-cycle. The objective of this paper is to develop a reliability model for flexible pavements that accounts for the effects of overlay designs. In this

Vighnesh P. Deshpande; Ivan D. Damnjanovic; Paolo Gardoni

2010-01-01

9

Truck fleet model for design and assessment of flexible pavements  

Microsoft Academic Search

The mechanistic empirical method of flexible pavement design\\/assessment uses a large number of numerical truck model runs to predict a history of dynamic load. The pattern of dynamic load distribution along the pavement is a key factor in the design\\/assessment of flexible pavement. While this can be measured in particular cases, there are no reliable methods of predicting the mean

Abraham Belay; Eugene Obrien; Dirk Kroese

2008-01-01

10

An evaluation of the flexible pavement design system FPS19  

E-print Network

The flexible pavement design program used by the Texas Department of Transportation (TXDOT) for the past 20 years, FPS1 1 , uses the Stiffness Coefficient, based on Dynaflect deflections, to characterize pavement strength. The difficulty...

Carmona, Gerardo M

2012-06-07

11

Pavement performance equations. Final report  

SciTech Connect

The WSDOT PMS data base was used to develop regression equations for three pavement surface types: bituminous surface treatments, asphalt concrete, and portland-cement concrete. The primary regression equations developed were to predict Pavement Condition Rating (PCR) which is a measure of the pavement surface distress (ranges from 100 (no distress) to below 0 (extensive distress)). Overall, the equations fit the data rather well given the expected variation of pavement performance information. The relative effects of age (time since construction or reconstruction) were illustrated for the three surface types.

Mahoney, J.P.; Kay, R.K.; Jackson, N.C.

1988-03-01

12

Structural response of LVR flexible pavements at Mn/ROAD project  

SciTech Connect

Pavement surface deflection basins provide valuable information for the structural evaluation of flexible pavements. Surface deflection measurements are rapid, inexpensive, and nondestructive and are used frequently as an indicator of pavement structural capability and performance potential. In this study, falling weight deflectometer testing results on the conventional flexible pavements (asphalt concrete surface, granular base/subbase) and aggregate-surface/surface-treated test sections in the low-volume road loop at the Minnesota Road Research Project (Mn/ROAD) were analyzed to evaluate the effect of granular material quality on the pavement structural response. Asphalt concrete (AC) modulus and subgrade ``break-point`` modulus were back-calculated using algorithms previously developed at the University of Illinois. The surface deflections were normalized to the same AC modulus and subgrade modulus. The analyses show a limited effect of granular material quality on the pavement deflection response in the case of conventional flexible pavements. Because of higher granular layer stresses, the granular material quality effects on the pavement surface deflection response of surface-treated/aggregate-surface pavements are significant. Increased AC thickness reduces the effect of granular base quality on the pavement deflection response.

Garg, N.; Thompson, M.R. [Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering] [Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering

1999-05-01

13

of Concrete Pavements Joint PerformanCe  

E-print Network

practitioners under- stand how to optimize concrete pavement joint perfor- mance through the identificationof Concrete Pavements Joint PerformanCe interim Guide for optimum JUNE 2012 #12;#12;Interim Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2

14

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

E-print Network

............................................................................. 10 2.1.1 Modeling Component Level Demand and Capacity ........... 10 2.1.1.1 Fatigue Cracking ................................................. 11 2.1.1.2 Rutting ................................................................ 11 2.1.1.3 Pavement... ............................................................................ 44 3.3.1 Pavement Response Model for Critical Tensile Strain ....... 46 3.3.2 Fragility Model for Fatigue Cracking Failure ..................... 47 3.3.2.1 Before Rehabilitation Actions (Three-layer System...

Deshpande, Vighnesh Prakash

2009-05-15

15

Adaptive prediction of pavement performance  

E-print Network

Zulyaminayn, B. S, Bangladesh University of Engineering and Technology Chair of Advisory Committee Dr Roger E. Smith A Visual Basic 60 computer program for adjusting family performance curves in TM making reasonable predictions of individual pavement..., in years, and alpha, a horizontal asymptote factor that controls the maximum range of distress growth or ride loss, base of the natural logarithms (e = 2. 71828. . . ), chi, a weighting factor that controls performance, epsilon, a climate weightmg...

Zulyaminayn, Mohammed

2012-06-07

16

Field performance of geosynthetic reinforced pavements over expansive clay subgrades  

E-print Network

cracks on the pavement structures. Traditionally the problems related to flexible pavements over flexible pavements. 1 INTRODUCTION Basal reinforcement of pavement systems has been used for the purposes of the soil in the vicinity of the pave- ment shoulders (Figure 1a). This leads to settlements in the shoulder

Zornberg, Jorge G.

17

Minimizing Distress on Flexible Pavements Using Variable Tire Pressure  

Microsoft Academic Search

The potential of variable tire pressure technology to minimize distress on flexible pavements with thin asphalt surfacing layers and peat soil subgrade was evaluated using in-situ stress-strain data. Pavement interfacial strains and corresponding subgrade stresses imposed by a three-axle truck were measured and used to estimate the fatigue life of the surfacing layer. Three levels of truck wheel loads in

Philip M. O. Owende; Anton M. Hartman; Shane M. Ward; Michael D. Gilchrist; Michael J. O'Mahony

2001-01-01

18

The impact of material characteristics on tire pavement interaction noise for flexible pavements  

NASA Astrophysics Data System (ADS)

Noise pollution has recently been one of the growing problems all over the world. While there are many sources of the noise, traffic noise is the main contributor to the total environmental noise. Although there are different sources for traffic noise, the tire pavement interaction noise is the most dominant component within most city and highway limits. One of the ways to reduce the tire pavement noise is to improve the material characteristics of the pavements such that they produce less noise. In this study, the relationship between basic material characteristics (e.g., Hot Mix Asphalt (HMA) volumetrics) and sound generation and absorption characteristics of flexible pavements was investigated. In addition, the effect of linear visco-elastic properties (e.g., dynamic modulus (|E*|) and phase angle (delta)) on sound absorption was studied. In order to focus only on impact of material characteristics and overshadow the effect of surface texture, a novel laboratory tire pavement noise measurement simulator (TIPANOS) was developed. The statistical analysis results showed that although the individual material characteristics do not have appreciable influence on sound absorption, there is a significant correlation between sound pressure levels (SPL) and combination of several material and linear visco-elastic parameters.

Kocak, Salih

19

AN IMPROVED DYNAMIC MODEL FOR THE STUDY OF A FLEXIBLE PAVEMENT  

E-print Network

AN IMPROVED DYNAMIC MODEL FOR THE STUDY OF A FLEXIBLE PAVEMENT A. El Ayadi 1 , B. Picoux 1 , G to study a Falling Weight Deectometer test conducted on a exible pavement. These dynamic models take with in situ measurements recorded on an instrumented pavement; such a comparison has indicated the importance

Avignon et des Pays de Vaucluse, Université de

20

Truck fleet model for design and assessment of flexible pavements  

NASA Astrophysics Data System (ADS)

The mechanistic empirical method of flexible pavement design/assessment uses a large number of numerical truck model runs to predict a history of dynamic load. The pattern of dynamic load distribution along the pavement is a key factor in the design/assessment of flexible pavement. While this can be measured in particular cases, there are no reliable methods of predicting the mean pattern for typical traffic conditions. A simple linear quarter car model which aims to reproduce the mean and variance of dynamic loading of the truck fleet at a given site is developed here. This probabilistic model reflects the range and frequency of the different heavy trucks on the road and their dynamic properties. Multiple Sensor Weigh-in-Motion data can be used to calibrate the model. Truck properties such as suspension stiffness, suspension damping, sprung mass, unsprung mass and tyre stiffness are represented as randomly varying parameters in the fleet model. It is used to predict the statistical distribution of dynamic load at each measurement point. The concept is demonstrated by using a pre-defined truck fleet to calculate a pattern of statistical spatial repeatability and is tested by using that pattern to find the truck statistical properties that generated it.

Belay, Abraham; OBrien, Eugene; Kroese, Dirk

2008-04-01

21

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 #12;Overview 1. Hydrology of Permeable Pavements 2. Water Quality Performance 3. Hydraulic Performance However, a large number of installations STILL continue to be sub-standard 4 #12;Porous Pavement Design

22

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

PubMed Central

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

Ti?demir, Mesut

2014-01-01

23

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

PubMed

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

Ti?demir, Mesut

2014-01-01

24

Performance of segregated hot mix asphalt pavements  

Microsoft Academic Search

A laboratory study was conducted to evaluate the performance of segregated hot mix asphalt (HMA) pavements. The study involved simulating in-situ segregation of two current projects. Tests in the study were a laboratory wheel track test (PURWheel) and triaxial tests (including resilient modulus). For each project four segregation levels were determined based on field observation and subsequent analysis of gradation,

Zhenghao Wang

2000-01-01

25

Performance of continuously reinforced concrete pavements: Volume 6 -- CRC pavement design, construction, and performance. Final report, August 1990--December 1994  

SciTech Connect

This report is one of a series of reports prepared as part of a recent study sponsored by the Federal Highway Administration (FHWA) aimed at updating the state-of-the-art of the design, construction, maintenance, and rehabilitation of continuous reinforced concrete (CRC) pavements. The scope of work of the FHWA study included the following: (1) Conduct of a literature review and preparation of an annotated bibliography on CRC pavements and CRC overlays. (2) Conduct of a field investigation and laboratory testing related to 23 existing in-service pavement sections. This was done to evaluate the effect of various design features on CRC pavement performance, to identify any design or construction related problems, and to recommend procedures to improve CRC pavement technology. (3) Evaluation of the effectiveness of various maintenance and rehabilitation strategies for CRC pavements. (4) Preparation of a Summary Report on the current state of the practice for CRC pavements. Each of the above four items is addressed in a separate report. The following reports have been prepared under this study: Performance of CRC Pavements. Volume 1: Summary of Practice and Annotated Bibliography. Volume 2: Field Investigation of CRC Pavements. Volume 3: Analysis and Evaluation of Field Test Data. Volume 4: Resurfacing for CRC Pavements. Volume 5: Maintenance and Repair of CRC Pavements. Volume 6: CRC Pavement Design, Construction, and Performance. Volume 7: Summary. This report is Volume 6 in the series.

Zollinger, D.G.; Buch, N.; Xin, D.; Soares, J.

1999-02-01

26

On the characterization of flexible pavement rutting using creep model-based finite element analysis  

Microsoft Academic Search

A new approach for characterizing flexible pavement rutting using creep model-based finite element analysis (FEA) is presented in this paper. A matrix of FEA was carefully designed so that pavements with low and high traffic volumes, low and high rutting levels, and different structural layer thickness combinations were all included. Transverse wheel wander distribution and non-uniform tire contact stresses were

Hongbing Fang; John E. Haddock; Thomas D. White; Adam J. Hand

2004-01-01

27

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

28

Performance-Based Concrete Pavement Mix Design System Performance-Based Design Guide for New and Rehabilitated  

E-print Network

Strategic Research Plan #12;· Performance-Based Concrete Pavement Mix Design System · Performance-Based Design Guide for New and Rehabilitated Concrete Pavements · High-Speed Nondestructive Testing Pavements · High-Speed Concrete Pavement Rehabilitation and Construction · Concrete Pavement Business

29

Use of Falling Weight Deflectometer Data to Quantify the Relative Performance of Reinforced Pavement Sections  

E-print Network

Pavement Sections Joshi, R.V.1 , S.M. ASCE and Zornberg J.G.2 , PhD., P.E, A.M. ASCE 1 Research Assistant in Grimes County, Texas. The pavement involves eight different experimental cross sections including control the flexible pavement to environmental loading. The objective of this paper is to characterize the possible

Zornberg, Jorge G.

30

Asphaltic concrete overlays of rigid and flexible pavements  

NASA Astrophysics Data System (ADS)

The development of a mechanistic approach to overlay thickness selection is described. The procedure utilizes a deflection analysis to determine pavement rehabilitation needs. Design guides for selecting the overlay thickness are presented. Tolerable deflection-traffic load relationships and the deflection attenuation properties of asphaltic concrete were developed, representing the subgrade support conditions and properties of materials used in Louisiana. All deflection measurements on asphaltic concrete were corrected for the effect of temperature. Deflection measurements taken before and after overlay were also adjusted to minimize the effects of seasonal subgrade moisture variation.

Kinchen, R. W.; Temple, W. H.

1980-10-01

31

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

32

Pavement management  

SciTech Connect

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

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

1982-01-01

33

Evaluation and Development of Pavement Scores, Performance Models and Needs Estimates for the TXDOT Pavement Management Information System - Final Report.  

National Technical Information Service (NTIS)

This project conducted a thorough review of the existing Pavement Management Information System (PMIS) database, performance models, needs estimates, utility curves, and scores calculations, as well as a review of District practices concerning the three b...

A. Wimsatt, A. T. Papagiannakis, C. Chang-Albitres, C. Gurganus, I. Abdallah, J. Weissmann, N. Gharaibeh, S. Nazarian, S. Saliminejad, T. Freeman

2012-01-01

34

A Study of the Performance of Three Asphalt Pavement Rehabilitation Strategies  

Microsoft Academic Search

This study analyzes the performance of three common hot mix asphalt rehabilitation strategies on 149 pavements over a period of seven years. All three strategies place two-inch overlays on the pavement to be rehabilitated. The first strategy includes an overlay on the existing pavement after sweeping the surface and applying a tack coat. The second strategy places the overlay after

Christopher Schmidt

35

PAVEMENT PREDICTION PERFORMANCE MODELS AND RELATION WITH TRAFFIC FATALITIES AND INJURIES  

E-print Network

PAVEMENT PREDICTION PERFORMANCE MODELS AND RELATION WITH TRAFFIC FATALITIES AND INJURIES V. CEREZO.gothie@developpement-durable.gouv.fr ABSTRACT This paper presents some results of a study, which aimed at modelling pavement evolution, pavement characteristics and age. In a second part, non-linear regressions were used in view of obtaining

Boyer, Edmond

36

1 INTRODUCTION Flexural fatigue is one of the main failure modes in asphalt mixtures and flexible pavement  

E-print Network

1 INTRODUCTION Flexural fatigue is one of the main failure modes in asphalt mixtures and flexible or strain), depending on the mode of laoding. 1.1 Fatigue Flexural fatigue due to repeated traffic loading resistance and the stiffness modulus is necessary to use any design method of the flexible road pavements

Paris-Sud XI, Université de

37

Experimental Study on Geocell-Reinforced Flexible Pavements with Recycled Asphalt Pavement (RAP) Bases under Cyclic Loading  

E-print Network

ABSTRACT The reprocessed old hot mix asphalt (HMA) concrete also called "Recycled Asphalt Pavement (RAP)", if used to build new roads or to maintain existing roads, would have several benefits, such as preservation of natural resources for future...

Acharya, Bhagaban

2011-12-31

38

An elastoplastic model based on the shakedown concept for flexible pavements unbound granular materials  

NASA Astrophysics Data System (ADS)

Nowadays, the problem of rutting of flexible pavements linked to permanent deformations occurring in the unbound layers is taken into account only by mechanistic empirical formulas. Finite element modelling of realistic boundary value problems with incremental rheological models will lead to unrealistic calculation time for large cycle numbers. The objective of the authors is to present a simplified model which can be used to model the flexible pavements rutting with the finite elements framework. This method is based on the shakedown theory developed by Zarka which is usually associated to materials like steels. It has been adapted for granular materials by introducing a yield surface taking into account the mean stress influence on the mechanical behaviour and a dependency of the hardening modulus with the stress state. The Drucker-Prager yield surface has been used with a non-associated flow rule. Comparisons with repeated load triaxial tests carried out on a subgrade soil have been done. These comparisons underline the capabilities of the model to take into account the cyclic behaviour of unbound materials for roads. Finally, a discussion, dealing with the use of the simplified method within a finite element modelling of a full-scale experiment, is presented.

Habiballah, Taha; Chazallon, Cyrille

2005-05-01

39

Pavement Systems Analyses.  

National Technical Information Service (NTIS)

Contents: Prestressed concrete highway pavement at Dulles International Airport; Relative effects of structural variables on the performance of continuous pavements; Finite-element analysis of concrete slabs and its implications for rigid pavement design;...

B. F. Friberg, T. J. Pasko

1973-01-01

40

An investigation into the predictive performance of pavement marking retroreflectivity measured under various conditions of continuous wetting  

E-print Network

This thesis research investigated the predictive performance of pavement marking retroreflectivity measured under various conditions of continuous wetting. The researcher compared nighttime detection distance of pavement markings in simulated rain...

Pike, Adam Matthew

2007-04-25

41

Using finite element analysis of retroreflective raised pavement markers to recommend testing procedures for simulating their field performance  

E-print Network

Retroreflective Raised Pavement Markers (RRPMs) supplement other pavement markings to provide guidance to road users. Previous research concerning durability of the RRPMs suggests that their performance has been degrading over the years. One...

Agrawal, Ravi Prakash

2006-08-16

42

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

SciTech Connect

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

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

1998-08-01

43

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

SciTech Connect

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

NONE

1998-08-01

44

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

E-print Network

68 70 70 70 77 80 81 85 tx CHAPTER COMPARISON OF PERFORMANCE PERIODS EFFECT OF POISSON'S RATIO IV DEVELOPMENT OF RESEARCH DATABASE GENERAL LONG TERM PAVEMENT PERFORMANCE DATA Background . LTPP Experiments . Structure of the LTPP IMS... 68 70 70 70 77 80 81 85 tx CHAPTER COMPARISON OF PERFORMANCE PERIODS EFFECT OF POISSON'S RATIO IV DEVELOPMENT OF RESEARCH DATABASE GENERAL LONG TERM PAVEMENT PERFORMANCE DATA Background . LTPP Experiments . Structure of the LTPP IMS...

Mukherjee, Biswajit

2012-06-07

45

Enhancement of Pavement Maintenance Decision Making by Evaluating the Effectiveness of Pavement Maintenance Treatments.  

E-print Network

??The performance of different pavement maintenance treatments were evaluated by investigating practical projects collected from Tennessee Pavement Management System (PMS) and Long Term Pavement Performance… (more)

Dong, Qiao

2011-01-01

46

Evaluation and Development of Pavement Scores, Performance Models and Needs Estimates: Phase I Activities.  

National Technical Information Service (NTIS)

This report documents the results of two completed Phase I tasks for the project titled, Evaluation and Development of Pavement Scores, Performance Models and Needs Estimates. These tasks involved a literature review and a review of the current Texas Pave...

A. Wimsatt, N. G. Gharaibeh, T. Freeman, Y. Zou

2011-01-01

47

Contributions of performance-graded asphalt to low temperature cracking resistance of pavements. Final report  

SciTech Connect

The purpose of this research was to study and evaluate the role that asphalt cracking. As part of the Strategic Highway Research Program (SHRP) new specifications for asphalt binders were developed that are based on the performance of the material. The asphalt binder graded and specified according to these new performance-based specifications is called PG binder. These new specifications are commonly referred to as Superpave (Superior Performing Asphalt Pavement) binder specifications. A section of Interstate 64 in southern Indiana was experiencing severe low temperature cracking before it was reconstructed over the summers of 1995 and 1996. The binder used in the new pavement mixes was PG material. Dynamic Shear Rheometer (DSR) tests, Bending Beam Rheometer (BBR) tests, and viscosity tests were performed on this binder. Comparisons were made between test results obtained from the binders in the old pavement and the new pavement. All tests and comparisons were based on the Superpave binder specifications.

Loh, S.W.; Olek, J.

1999-05-01

48

A Methodology for Developing Performance-Related Specifications for Pavement Preservation Treatments  

E-print Network

Current materials and construction specifications for pavement preservation treatments are predominantly prescriptive and they have little or no methodical linkage between initial treatment quality and future performance. There is an imperative...

Liu, Litao

2013-09-23

49

An analysis of some properties of paving asphalts in Texas as they relate to pavement performance  

E-print Network

AN ANALYSIS OF SOME PROPERTIES OF PAVING ASPHALTS IN TEXAS AS THEY RELATE TO PAVEMENT PERFORMANCE A Thesis by EMMETT HAYGOOO DUBOSE, JR. Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August, 1980 Major Subject: Civil Engineering AN ANALYSIS OF SOME PROPERTIES OF PAVING ASPHALTS IN TEXAS AS THEY RELATE TO PAVEMENT PERFORMANCE A Thesis by EMMETT HAYGOOD DUBOSE, JR. Approved as to style and content by...

DuBose, Emmett Haygood

2012-06-07

50

Characterization of Fatigue Performance of WesTrack Pavement Using Work Potential Theory  

Microsoft Academic Search

Superior Performing Asphalt Pavement (SuperPave) is the final product of SHRP asphalt research program and has been adopted by most of the state highway agencies in the united states. However, results from a well-controlled experimental construction project, WesTrack, are against SuperPave volumetric design method. For WesTrack pavements, the asphalt mixes with fine gradation performed than mixes with coarse gradation better

Haifang Wen

2003-01-01

51

Assessment of durability performance of "Early-Opening-to-Traffic" Portland Cement Concrete pavement and patches  

E-print Network

ASSESSMENT OF DURABILITY PERFORMANCE OF "EARLY-OPENING-TO-TRAFFIC" PORTLAND CEMENT CONCRETE PAVEMENT AND PATCHES A Thesis by PRADHUMNA BABU SHRESTHA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of thc requirements for the degree of M A STER OF SCIENCE August 1999 Major Subject: Civil Engineering ASSESSMENT OF DURABILITY PERFORMANCE OF "EARLY-OPENING-TO-TRAFFIC" PORTLAND CEMENT CONCRETE PAVEMENT AND PATCHES A Thesis by PRADHUMNA BABU...

Shrestha, Pradhumna Babu

2012-06-07

52

Performance Prediction of the NCAT Test Track Pavements Using Mechanistic Models  

NASA Astrophysics Data System (ADS)

In the pavement industry in the United States of America, there is an increasing desire to improve the pavement construction quality and life for new and rehabilitated pavements. In order to improve the quality of the pavements, the Federal Highway Administration (FHWA) has pursued a performance-related specification (PRS) for over 20 years. The goal of PRS is to provide material and construction (M/C) properties that correlate well with pavement performance. In order to improve upon the PRS projects developed in WesTrack (NCHRP 9-20) and the MEPDG-based PRS (NCHRP 9-22), a set of PRS tests and models are proposed to provide a critical link between pavement performance and M/C properties. The PRS testing is done using the asphalt mixture performance tester (AMPT). The proposed PRS focuses on rutting and fatigue cracking of asphalt mixtures. The mixtures are characterized for their stiffness, fatigue behavior, and rutting resistance using a dynamic modulus (|E*|) test, a fatigue test, and a triaxial stress sweep (TSS) test, respectively. Information from the fatigue test characterizes the simplified viscoelastic continuum damage (S-VECD) model. Once the stiffness is reduced to a certain level, the material develops macro-cracks and fails. The TSS test is used to characterize a viscoplastic (VP) model. The VP model allows the prediction of the rut depth beneath the center of the wheel. The VECD and VP models are used within a layered viscoelastic (LVE) pavement model to predict fatigue and rutting performance of pavements. The PRS is evaluated by comparing the predictions to the field performance at the NCAT pavement test track in Opelika, Alabama. The test track sections evaluated are part of the 2009 test cycle group experiment, which focused on WMA, high RAP (50%), and a combination of both. The fatigue evaluation shows that all sections would last at least 18 years at the same traffic rate. The sections do not show any cracking, suggesting the sections are well-built and a long life is possible. The rutting in the test track is also predicted. All the predicted rut depths are 2-4 mm higher than measured in the field, but the overall ranking of different pavement sections matches the ranking in the field quite well. Conclusions and recommendations for future research are drawn from the observations made from experimental results as well as performance prediction of NCAT pavement sections.

LaCroix, Andrew Thomas

53

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

54

Performance of concrete pavements containing recycled concrete aggregate. Interim report, October 1993-October 1996  

SciTech Connect

This interim report documents the field performance of nine concrete pavement projects that incorporate recycled concrete aggregate (RCA) in the construction of the pavement. Multiple sections were evaluated on many of the nine projects, due to perceived differences in performance levels or variations in pavement design (such as the use of virgin aggregate or the inclusion of dowel bars). All told, a total of 17 sections (of which 12 contain RCA) were subjected to an extensive field testing program, consisting of pavement condition surveys, drainage surveys, falling weight deflectometer (FWD) testing, coring, and serviceability assessments. A minimum of eight cores were retrieved from each section for laboratory evaluation of compressive strength, split tensile strength, dynamic elastic modulus, static elastic modulus, and thermal coefficient of expansion, as well as for volumetric surface testing and petrographic analyses.

Wade, M.J.; Cuttell, G.D.; Vandenbossche, J.M.; Yu, H.T.; Smith, K.D.

1997-03-01

55

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

E-print Network

Unbound granular materials are generally used in road pavements as base and subbase layers. The granular materials provide load distribution through aggregate contacts to a level that can help the subgrade to withstand the applied loads. Several...

Masad, Sanaa Ahmad

2004-09-30

56

PERFORMANCE-BASED CONTRACTING IN CONSTRUCTION PHASE AND MAINTENANCE PHASE OF PAVEMENT  

NASA Astrophysics Data System (ADS)

Performance-based contracting for pavement in Japan started as performance warranties in construction phase, in 1999. Recently, road agencies have recognized the applicability of this type of contracting in outsourcing of maintenance activities. The objectives of this study are to clarify the issues of performance specifying in construction phase and maintenance phase of pavement, and to propose measures to be taken. This paper, with the recognition that the life of each pavement depends on performance standards for various attributes, reviews domestic and foreign examples of performance-based contracting. A performance standard based on the average of current practices can enhance product quality and service life with a warranty contract. Repair thresholds and response time for each deficiency should be considered as performance standards in maintenance phase.

Yoshida, Takeshi

57

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

58

LONG-TERM PERFORMANCE OF HIGH-VOLUME FLY ASH CONCRETE-PAVEMENTS  

Microsoft Academic Search

This investigation was undertaken to evaluate the long -term performance of concrete pavements made with high volumes of Class F and Class C fly ash (FA). Six different mixtures, three mixtures with Class C fly ash up to 70% cement replacement and three mixtures with Class F fly ash up to 60% cement replacement, were used. Long-term performance tests were

Tarun R. Naik; Shiw S. Singh; Rudolph N. Kraus; Bruce W. Ramme

59

Development of Pavement Performance Models by Combining Experimental and Field Data  

Microsoft Academic Search

The objective of this paper is to demonstrate the development of pavement performance models by combining experimental and field data. A two step approach was used. In the first step a riding quality model based on serviceability consideration is developed. The data set of the American Association of State Highways Officials~AASHO! Road Test is used to this effect. Due to

J. A. Prozzi

2004-01-01

60

Assessment of the performance of rigid pavement back-calculation through finite element modeling  

NASA Astrophysics Data System (ADS)

This study focuses on examining the behavior of rigid pavement layers during the Falling Weight Deflectometer (FWD) test. Factors affecting the design of a concrete slab, such as whether the joints are doweled or undoweled and the spacing between the transverse joints, were considered in this study. Explicit finite element analysis was employed to investigate pavement layers' responses to the action of the impulse of the FWD test. Models of various dimensions were developed to satisfy the factors under consideration. The accuracy of the finite element models developed in this investigation was verified by comparing the finite element- generated deflection basin with that experimentally measured during an actual test. The results showed that the measured deflection basin can be reproduced through finite element modeling of the pavement structure. The resulting deflection basins from the use FE modeling was processed in order to backcalculate pavement layer moduli. This approach provides a method for the evaluation of the performance of existing backcalculation programs which are based on static elastic layer analysis. Based upon the previous studies conducted for the selection of software, three different backcalculation programs were chosen for the evaluation: MODULUS5.0, EVERCALC4.0, and MODCOMP3. The results indicate that ignoring the dynamic nature of the load may lead to crude results, especially during backcalculation procedures.

Shoukry, Samir N.; William, Gergis W.; Martinelli, David R.

1999-02-01

61

Effects of an uncrushed base layer on pavement performance. Final report  

SciTech Connect

In 1974, the Alaska Department of Highways decided to save money and fuel by removing the base course and placing the asphalt-concrete surface directly on the surface of the Glenn Highway Widening project. The original two lanes had been constructed with a crushed-base course in 1969, thus providing an excellent comparison of the performance of the two bases. Results showed that the uncrushed base course performed better than the crushed-base course: the resilient modulus was higher and the permanent deformation was lower. The uncrushed base is apparently superior because of a larger maximum particle size and greater maximum density. An analysis of the future performance of the roadway with equal thickness of asphalt indicates that the pavement over the uncrushed base would have a longer life than the pavement over the crushed base by 54%.

Johnson, E.G.; Hicks, R.G.

1987-06-01

62

Pavement evaluation and rehabilitation  

SciTech Connect

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

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

1987-01-01

63

Pavement condition data analysis  

SciTech Connect

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

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

1987-07-01

64

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

65

Stochastic Modeling of Future Highway Maintenance Costs for Flexible Type Highway Pavement Construction Projects  

E-print Network

increased needs to rebuild deteriorated transportation networks. For major highway maintenance projects, a federal rule enforces to perform a life-cycle cost analysis (LCCA). The lack of analytical methods for LCCA creates many challenges of STAs to comply...

Kim, Yoo Hyun

2012-07-16

66

Material characterization for studing flexible pavement behavior in fatigue and permanent deformation  

Microsoft Academic Search

Mixtures' performances in fatigue and rutting were investigated. Different aggregates and gradations were studied in these mixtures. The aggregates and gradations chosen were investigated using Marshall design criteria. These aggregates were first evaluated for basic material characteristics such as specific gravity and water absorption for both fine and course fractions. Also, the Marshall stability, density and air voids contents were

M. R. N. Elmitiny

1980-01-01

67

Exploring Performance-Based Solutions & Design Flexibility  

E-print Network

& Guidance To Think & Act Differently #12;Design Flexibility vs. Standards AASHTO "Green Book" A series Objectives Within Overly Conservative Design Approaches & Standards #12;www. dot.state.mn.us (Search A to ZExploring Performance-Based Solutions & Design Flexibility Scott Bradley & Greg Ous - MN Dept

Minnesota, University of

68

Influence of Recycled Asphalt Pavement on Fatigue Performance of Asphalt Concrete Base Courses  

Microsoft Academic Search

This paper presents the physical properties of recycled asphalt pavement RAP and its influence on the mechanical perfor- mance of a binder course asphalt pavement mix. A series of binder course mixes were designed containing varying percentages of RAP. A mix made from only virgin material was selected as the control mix for the investigation. The effect of introducing RAP

Amir Tabakovic?; Amanda Gibney; Ciaran McNally; Michael D. Gilchrist

2010-01-01

69

Life-Cycle Economic Performance for Hot Mix Asphalt Pavement Rehabilitation Strategies  

Microsoft Academic Search

Hot mix asphalt pavements comprise approximately 96% of the paved roadway surfaces in North America. Strategies employed to rehabilitate these surfaces vary widely at a cost of approximately $600 million annually. The Colorado Department of Transportation maintains approximately 28,000 lane miles of asphalt pavements. Of the many rehabilitation strategies employed to maintain this network, three strategies have been utilized most

Scott Shuler; Christopher Schmidt; Jay Goldbaum

2010-01-01

70

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

71

Estimating flexible pavement maintenance and rehabilitation fund requirements for a transportation network. Research report (Interim) September 1984-February 1988  

SciTech Connect

In the early 1980's the Texas State Department of Highways and Public Transportation implemented its Pavement Evaluation System. The system was designed to (a) document trends in network condition and (b) generate a one-year estimate of rehabilitation funding. The information generated by the system was used for many purposes including funding request, project prioritization and documenting the consequences of changes in funding levels. However, a limitation of the system was its inability to project future conditions and make multi-year needs estimates. This is the subject of the report. Regression equations were built for each major distress type from a pavement data base containing a 10-year history of condition trends from over 350 random sections in Texas. These equations were used to age individual sections that did not qualify for maintenance or rehabilitation in a particular year. A simple decision tree was developed to estimate the maintenance requirements if rehabilitation is not warranted. The decision-tree represents the opinions of experienced maintenance engineers. A case study and sensitivity analysis are presented.

Stein, A.; Scullion, T.

1988-02-01

72

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

73

IMPLEMENTATION OF A DATABASE AND INFORMATION SYSTEM FOR FORENSIC INVESTIGATION OF PAVEMENTS 6. Performing Organization Code  

Microsoft Academic Search

16. Abstract This report describes the implementation of a database and information system for forensic investigation of pavements by enhancing the 1998 version of the ForenSys database software. The enhanced ForenSys database software can serve as the center component of an integrated forensic information and analysis system for analyzing forensic related data and information and producing forensic reports. In the

Zhanmin Zhang; Chunrong Zhou

74

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

75

LRRB Pavement Management Systems Pavement Management Systems  

E-print Network

LRRB Pavement Management Systems Pavement Management Systems Presented by: Michael Marti SRF for implementing and monitoring research results (RIC) #12;LRRB Pavement Management Systems LRRB Structure LRRB and counties in implementing Pavement Management and/or using better §Project produced several deliverables

Minnesota, University of

76

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

E-print Network

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.... Acknowledgements are due Mr. R. E. Schiller, Associate Professor of Civil Engineering, and Dr. W. H. Nedderman, Professor of Civil Engineering, for their helpful assistance in reviewing the manuscript; and to Mr. L. E. Stark, Associate Research Engineer, and Mr...

Meyer, Kirby Thomas

2012-06-07

77

Macroscopic, flexible, high-performance graphene ribbons.  

PubMed

Tailoring the structure and properties of graphene fibers is an important step toward practical applications. Here, we report macroscopic, long graphene ribbons formed by combining electrostatic interaction and shear stress during the wet-spinning process. The graphene ribbons are flexible and can be woven into complex structures, and the ribbon morphology can be tailored by controlling the orientation of wrinkles to obtain elasticity within a modest strain. We demonstrate several potential applications of pure or Pt-graphene hybrid ribbons as elastic strain sensors, counter electrodes for dye-sensitized fiber solar cells with cell efficiencies reaching 4.69% under standard illumination and 6.41% with a back reflector, and woven fabric supercapacitor electrodes. Our method can directly fabricate meter-long graphene ribbons with controlled structure and high performance as both energy conversion and energy storage materials. PMID:24164512

Sun, Jiankun; Li, Yanhui; Peng, Qingyu; Hou, Shaocong; Zou, Dechun; Shang, Yuanyuan; Li, Yibin; Li, Peixu; Du, Qiuju; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua; Li, Xianglong; Cao, Anyuan

2013-11-26

78

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

79

The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Cooperative Highway Research Program (NCHRP) Project 1-37A represents a major change as compared to the 1993 AASHTO Pavement  

E-print Network

The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National AASHTO Pavement Design Guide. MEPDG provides a rational pavement design framework based on the pavement performance. Before replacing the 1993 Pavement Design Guide (and its accompanying DARWin 3

Harms, Kyle E.

80

The impact of fine aggregate characteristics on asphalt concrete pavement design life  

Microsoft Academic Search

The development of the Mechanistic–Empirical Pavement Design Guide (MEPDG) provides an opportunity to simulate the performance of pavements. This paper considers the impact of fine aggregate on the predicted performances of pavements by simulating the performance differences between pavement mixes prepared with different sources of fine aggregate with different gradations using the MEPDG. A natural and four manufactured sands from

Tamer M. Breakah; Jason P. Bausano; R. Christopher Williams; Stan Vitton

2011-01-01

81

CONCRETE PAVEMENT Reference Manual  

E-print Network

CONCRETE PAVEMENT Reference Manual Prepared for Federal Highway Administration Office of Pavement by National Concrete Pavement Technology Center at Iowa State University 2711 South Loop Drive, Suite 4700 No. 3. Recipient's Catalog No. 4. Title and Subtitle 5. Report Date February 2008 Concrete Pavement

82

SOURCE: UNIVERSITY OF CALIFORNIA PAVEMENT RESEARCH CENTER PAVEMENT TECHNOLOGY UPDATE  

E-print Network

SOURCE: UNIVERSITY OF CALIFORNIA PAVEMENT RESEARCH CENTER PAVEMENT TECHNOLOGY UPDATE at the California Department of Transportation. Content is provided by the University of California Pavement Research Center. The University of California Pavement Research Center Using innovative research and sound

California at Berkeley, University of

83

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

E-print Network

The falling weight deflectometer (FWD) test is one of the most com- monly used tools- calculation of the pavement elastic moduli from falling weight deflectometer (FWD) measurements is a well, elastostatic-based interpretation of the falling weight­induced force and deflection records remains the norm

Guzina, Bojan

84

MANUAL FOR WEB-BASED TXDOT RIGID PAVEMENT Sureel Saraf  

E-print Network

0-5445-P2 MANUAL FOR WEB-BASED TXDOT RIGID PAVEMENT DATABASE Authors: Sureel Saraf Moon Won TxDOT Project 0-5445: Project Level Performance Database for Rigid Pavements in Texas SEPTEMBER 2007, REV. JULY-Based Information System for Rigid Pavements User's Manual Texas Department of Transportation July 9, 2009 #12

Texas at Austin, University of

85

Influence of vehicular positions and thermal effects on structural behaviour of concrete pavement  

Microsoft Academic Search

Structural response of concrete pavements is influenced by the position of the axle loads and if critical load positions are not considered in concrete pavement analysis, the design may be inadequate and lead to early failure of the pavement. Whilst there has been a great deal of research conducted on concrete pavement performance and deterioration under vehicular loads and environmental

David P. Thambiratnam; Andreas Nataatmadja; Daksh Baweja

86

Lower bound shakedown analysis of layered pavements using discontinuous stress fields  

Microsoft Academic Search

Pavements and railways are subjected to repeated wheel loads of different magnitudes. Both load magnitudes and number of repetitions of load need to be considered in order to avoid significant damages to a pavement. A conventional finite element technique is convenient for calculating static pavement responses, but the prediction of pavement performance under repeated loading is much more difficult as

H. S. Yu; M. Z. Hossain

1998-01-01

87

Predicting pavement distress in oil field areas  

SciTech Connect

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

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

1983-05-01

88

Predicting pavement distress in oil field areas  

SciTech Connect

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

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

1984-05-01

89

Flexible Nanoscale High-Performance FinFETs.  

PubMed

With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics. PMID:25185112

Torres Sevilla, Galo A; Ghoneim, Mohamed T; Fahad, Hossain; Rojas, Jhonathan P; Hussain, Aftab M; Hussain, Muhammad Mustafa

2014-10-28

90

Flexible, High Performance Convolutional Neural Networks for Image Classification  

E-print Network

Flexible, High Performance Convolutional Neural Networks for Image Classification Dan C. Cires, fully parameterizable GPU im- plementation of Convolutional Neural Network variants. Our feature; Mutch and Lowe, 2008], whose filters are fixed, in contrast to those of Convolutional Neural Networks

Schmidhuber, Juergen

91

Recycling of pavement materials  

E-print Network

materials. A comparison was made between the recycled pavements and typical conventional asphalt concrete pavements. An economic asse?sment of thc recycled pavements was made to determine thc economic feasibility of recycling. Results of laboratory... evaluations show that: recycled pavement mixtures possess properties equivalent to conventional asphalt concrete mixtures; and rccvcl inI' con ho accom- plished with conventional ertuapment. kyar po I'lotion associated with hot-mix recycling of asphalt...

O'Neal, Randy Jim

2012-06-07

92

Application Performance and Flexibility on Exokernel Systems  

Microsoft Academic Search

The exokernel operating system architecture safely gives untrusted software efficient control over hardware and software resources by separating management from protection. This paper describes an exokernel system that allows specialized applications to achieve high performance without sacrificing the performance of unmod- ified UNIX programs. It evaluates the exokernel architecture by measuring end-to-end application performance on Xok, an exo- kernel for

M. Frans Kaashoek; Dawson R. Engler; Gregory R. Ganger; Héctor M. Briceño; Russell Hunt; David Mazières; Thomas Pinckney; Robert Grimm; John Jannotti; Kenneth Mackenzie

1997-01-01

93

STONE PAVEMENTS IN DESERTS  

Microsoft Academic Search

Stone pavements are armored surfaces comprising intricate mosaics of coarse particles, usually only one or two stones thick, set on or in fine material. They occur widely in many unvegetated areas, and preeminently in hot deserts. Pavement studies in several deserts, and especially in Chile and California, suggest that: 1) deflation may be a relatively unimportant process of pavement formation;

RONALD U. COOKE

1970-01-01

94

Flexibility.  

ERIC Educational Resources Information Center

Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

Humphrey, L. Dennis

1981-01-01

95

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...

96

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

SciTech Connect

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

Pierce, L.M.

1996-01-01

97

High-performance, flexible, deployable array development for space applications  

NASA Technical Reports Server (NTRS)

Flexible, deployable arrays are an attractive alternative to conventional solar arrays for near-term and future space power applications, particularly due to their potential for high specific power and low storage volume. Combined with low-cost flexible thin-film photovoltaics, these arrays have the potential to become an enabling or an enhancing technology for many missions. In order to expedite the acceptance of thin-film photovoltaics for space applications, however, parallel development of flexible photovoltaics and the corresponding deployable structure is essential. Many innovative technologies must be incorporated in these arrays to ensure a significant performance increase over conventional technologies. For example, innovative mechanisms which employ shape memory alloys for storage latches, deployment mechanisms, and array positioning gimbals can be incorporated into flexible array design with significant improvement in the areas of cost, weight, and reliability. This paper discusses recent activities at Martin Marietta regarding the development of flexible, deployable solar array technology. Particular emphasis is placed on the novel use of shape memory alloys for lightweight deployment elements to improve the overall specific power of the array. Array performance projections with flexible thin-film copper-indium-diselenide (CIS) are presented, and government-sponsored solar array programs recently initiated at Martin Marietta through NASA and Air Force Phillips Laboratory are discussed.

Gehling, Russell N.; Armstrong, Joseph H.; Misra, Mohan S.

1994-01-01

98

4/28/2010 1Porous Pavements Porous Pavements  

E-print Network

benefits Why Look at New Pavement Approaches? #12;4/28/2010 4Porous Pavements 4Porous Pavements Alternative) ·! Farmington Schools - Parking lot ·! Mound Commercial Center - Parking lot ·! Park Rapids Mixed Use

Minnesota, University of

99

12th Annual Minnesota Pavement  

E-print Network

12th Annual Minnesota Pavement Conference: Session Summaries Conference Sponsors: Minnesota Research Alliance (TERRA) Pavement Research Institute (PRI) Hosted by: Center for Transportation Studies provides information to practitioners and others in pavement design, construction, and maintenance

Minnesota, University of

100

Flexibility in logistic systems—modeling and performance evaluation  

Microsoft Academic Search

This paper examines potential benefits of flexibility in logistic systems. It briefly reviews flexibility concepts and existing flexibility frameworks before suggesting a bottom-up framework for flexibility in logistic systems. Then, one among the proposed system logistic flexibility types, denoted here trans-routing flexibility, is quantitatively investigated. The research focuses on flexibility's benefits exclusive of cost considerations. Logistics dependability, a customer oriented

M. Barad; D. Even Sapir

2003-01-01

101

ORIGINAL PAPER Rapid cognitive flexibility of rhesus macaques performing  

E-print Network

ORIGINAL PAPER Rapid cognitive flexibility of rhesus macaques performing psychophysical task-switching. These rapid and unpredictable changes constitute a task-switching paradigm, in which subjects must encode task demands and shift to whichever task-set is presently activated. In con- trast to the widely reported task-switching

Terrace, Herbert S.

102

Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions  

NASA Technical Reports Server (NTRS)

Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

2001-01-01

103

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

SciTech Connect

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

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

1987-01-01

104

Community orientation, strategic flexibility, and financial performance in hospitals.  

PubMed

The objective of this study was to examine how community orientation and strategic flexibility affect accounting measures of financial performance in acute care hospitals. This cross-sectional study used organizational data from the American Hospital Association, environmental data from the Area Resource File, and financial data from the Healthcare Cost Report Information System. We tested our hypotheses on 1,779 hospitals using OLS regression models that controlled for organizational and environmental factors that might affect financial performance. The community orientation of a hospital had a negative impact on its short-term financial performance. However, the strategic flexibility of a hospital with regard to structure and resources was significantly and positively associated with hospital performance. Our findings are important to healthcare managers. Specifically, although a community orientation is thought to be essential for improving the health of populations, the healthcare market may lack clarity concerning the wants and needs of patients and payers to such a degree that this orientation does not result in improved short-term financial performance. In contrast, when a hospital maintains flexibility in its resource allocations and organizational structure, it can meet changing needs and uncertainties and thereby enhance financial performance. PMID:16605221

Ginn, Gregory O; Lee, Ruby P

2006-01-01

105

High-performance graphene-based transparent flexible heaters.  

PubMed

We demonstrate high-performance, flexible, transparent heaters based on large-scale graphene films synthesized by chemical vapor deposition on Cu foils. After multiple transfers and chemical doping processes, the graphene films show sheet resistance as low as ?43 Ohm/sq with ?89% optical transmittance, which are ideal as low-voltage transparent heaters. Time-dependent temperature profiles and heat distribution analyses show that the performance of graphene-based heaters is superior to that of conventional transparent heaters based on indium tin oxide. In addition, we confirmed that mechanical strain as high as ?4% did not substantially affect heater performance. Therefore, graphene-based, flexible, transparent heaters are expected to find uses in a broad range of applications, including automobile defogging/deicing systems and heatable smart windows. PMID:22082041

Kang, Junmo; Kim, Hyeongkeun; Kim, Keun Soo; Lee, Seoung-Ki; Bae, Sukang; Ahn, Jong-Hyun; Kim, Young-Jin; Choi, Jae-Boong; Hong, Byung Hee

2011-12-14

106

Road Materials and Pavements Design. Volume X No X/2013, pages 1 to n Review of glass fiber grid use for pavement  

E-print Network

Road Materials and Pavements Design. Volume X No X/2013, pages 1 to n Review of glass fiber grid use for pavement reinforcement and APT experiments at IFSTTAR Mai Lan Nguyen* Juliette Blanc* Jean performance, to extend service life and thus to reduce maintenance costs of road pavements. Among a large

Paris-Sud XI, Université de

107

Pavement Thickness Design Parameter  

E-print Network

Pavement Thickness Design Parameter Impacts 2012 Municipal Streets Seminar November 14, 2012 Paul D Thickness Design · Design Traffic ­ Average daily traffic volume ­ Percent trucks on the street · Usually 2RoadXpress (Asphalt Institute) ­ American Concrete Paving Association · StreetPave ­ AASHTO 1993 Pavement Design Guide

108

Asphalt in Pavement Maintenance.  

ERIC Educational Resources Information Center

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

Asphalt Inst., College Park, MD.

109

Pavement Design TTP Orientation Seminar  

E-print Network

Pavement Design TTP Orientation Seminar 2013 #12;What are Pavements? · Engineered structures vehicles ­Freight and freight handling ­Trains and trams ­Aircraft and spacecraft #12;Pavement Types · Surface Treatment ­ Thin sprayed asphalt on granular bases · Permeable Pavement ­ Open graded asphalt

Handy, Susan L.

110

Pavement Design TTP Orientation Seminar  

E-print Network

Pavement Design TTP Orientation Seminar 2010 #12;What are Pavements? · Engineered structures vehicles ­Freight and freight handling ­Trains and trams ­Aircraft and spacecraft #12;Pavement Types · Surface Treatment ­ Thin sprayed asphalt on granular bases · Permeable Pavement ­ Open graded asphalt

Handy, Susan L.

111

Pavement Design TTP Orientation Seminar  

E-print Network

Pavement Design TTP Orientation Seminar 2011 #12;What are Pavements? · Engineered structures vehicles ­Freight and freight handling ­Trains and trams ­Aircraft and spacecraft #12;Pavement Types · Surface Treatment ­ Thin sprayed asphalt on granular bases · Permeable Pavement ­ Open graded asphalt

Handy, Susan L.

112

An advanced algorithm for highway pavement fissure detection  

NASA Astrophysics Data System (ADS)

This paper presents image detection method of pavement crack based on fractal dimension feature and designs self-adapting algorithm of fractal dimension interval of pavement region. Through image pretreatment, calculation of fractal dimension, self-adapting calculation of dimension interval, we obtain the location image of damage pavement. The experimental results of transverse crack, longitudinal crack, net-shaped crack, pit slot are contrast with that of Sobel operator. The results show that they have the similar capability on the representation of crack, but the proposed method is more flexible on the aspect of representation of crack size and calculation of damage ratio.

Chen, Bei; Cao, Wenlun; He, Yuyao

2012-04-01

113

Pavement management practices. Final report  

SciTech Connect

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

Peterson, D.E.

1987-11-01

114

Resonance and propulsion performance of a heaving flexible wing  

NASA Astrophysics Data System (ADS)

The influence of the bending rigidity of a flexible heaving wing on its propulsive performance in a two-dimensional imposed parallel flow is investigated in the inviscid limit. Potential flow theory is used to describe the flow over the flapping wing. The vortical wake of the wing is accounted for by the shedding of point vortices with unsteady intensity from the wing's trailing edge. The trailing-edge flapping amplitude is shown to be maximal for a discrete set of values of the rigidity, at which a resonance occurs between the forcing frequency and a natural frequency of the system. A quantitative comparison of the position of these resonances with linear stability analysis results is presented. Such resonances induce maximum values of the mean developed thrust and power input. The flapping efficiency is also shown to be greatly enhanced by flexibility.

Michelin, Sébastien; Llewellyn Smith, Stefan G.

2009-07-01

115

Flow structure and performance of a flexible plunging airfoil  

NASA Astrophysics Data System (ADS)

An investigation was performed with the intent of characterizing the effect of flexibility on a plunging airfoil, over a parameter space applicable to birds and flapping MAVs. The kinematics of the motion was determined using of a high speed camera, and the deformations and strains involved in the motion were examined. The vortex dynamics associated with the plunging motion were mapped out using particle image velocimetry (PIV), and categorized according to the behavior of the leading edge vortex (LEV). The development and shedding process of the LEVs was also studied, along with their flow trajectories. Results of the flexible airfoils were compared to similar cases performed with a rigid airfoil, so as to determine the effects caused by flexibility. Aerodynamic loads of the airfoils were also measured using a force sensor, and the recorded thrust, lift and power coefficients were analyzed for dependencies, as was the overall propulsive efficiency. Thrust and power coefficients were found to scale with the Strouhal number defined by the trialing edge amplitude, causing the data of the flexible airfoils to collapse down to a single curve. The lift coefficient was likewise found to scale with trailing edge Strouhal number; however, its data tended to collapse down to a linear relationship. On the other hand, the wake classification and the propulsive efficiency were more successfully scaled by the reduced frequency of the motion. The circulation of the LEV was determined in each case and the resulting data was scaled using a parameter developed for this specific study, which provided significant collapse of the data throughout the entire parameter space tested.

Akkala, James Marcus

116

5-9035-01-P3 4-YEAR PAVEMENT MANAGEMENT PLAN  

E-print Network

5-9035-01-P3 4-YEAR PAVEMENT MANAGEMENT PLAN: ANALYSIS REPORT Authors: Zhanmin Zhang Michael R to Provide Information for Pavement Maintenance Decision-Making OCTOBER 2009 Performing Organization: Center and the Federal Highway Administration. #12;#12;iii Table of Contents Section 1. Pavement Management Plan

Texas at Austin, University of

117

7. Low temperature cracking in HMA Pavement Cracking Al-Qadi, Scarpas & Loizos (eds)  

E-print Network

7. Low temperature cracking in HMA 367 #12;#12;Pavement Cracking � Al-Qadi, Scarpas & Loizos (eds, Storrs, Connecticut, USA ABSTRACT: Low temperature cracking remains one of the major pavement distresses in asphalt concrete pavements in cold regions. An integrated laboratory testing, field performance data

Paulino, Glaucio H.

118

Contact based analysis of asphalt pavement with the effect of aggregate angularity  

Microsoft Academic Search

Relating the performance behavior of asphalt pavement with its design parameters may provide the insight information of how to control and improve the quality of asphalt pavement. The relation must be developed in a functional form so the effect of design parameters on the overall stress–strain response of asphalt pavement then can be quantified based on a single-variable perturbation. This

Han Zhu; Julie E. Nodes

2000-01-01

119

PAVEMENT TECHNOLOGY UPDATE This Technology Transfer Program  

E-print Network

PAVEMENT TECHNOLOGY UPDATE This Technology Transfer Program publication is funded by the Division by the University of California Pavement Research Center. The University of California Pavement Research Center Using innovative research and sound engineering principles to improve pavement structures, materials

California at Berkeley, University of

120

Pavement conference..............2 Eno award ...............................3  

E-print Network

· Pavement conference..............2 · Eno award ...............................3 · ITSO conference work with intelligent pavement, which elimi- nates the need for external sensors by enabling the pavement itself to detect vehicles. Yu cre- ates the pavement by incorporating carbon nanotubes

Minnesota, University of

121

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

2012-06-07

122

Local Calibration for Fatigue Cracking Models Used in the Mechanistic Empirical Pavement Design Guide  

Microsoft Academic Search

This paper identified two important calibration factors for a Midwest implementation of the Mechanistic- Empirical Pavement Design Guide (MEPDG). The calibration factors are for the fatigue damage model in flexible pavements. The gathering of the data required for calibration is labor intensive because the data resides in various and incongruent data sets. Spreadsheet templates specifically designed to manage the calibration

Teresa M. Adams

123

Semiconducor wires and ribbons for high performance flexible electronics.  

SciTech Connect

This article reviews the properties, fabrication and assembly of inorganic semiconductor materials that can be used as active building blocks to form high-performance transistors and circuits for flexible and bendable large-area electronics. Obtaining high performance on low temperature polymeric substrates represents a technical challenge for macroelectronics. Therefore, the fabrication of high quality inorganic materials in the form of wires, ribbons, membranes, sheets, and bars formed by bottom-up and top-down approaches, and the assembly strategies used to deposit these thin films onto plastic substrates will be emphasized. Substantial progress has been made in creating inorganic semiconducting materials that are stretchable and bendable, and the description of the mechanics of these form factors will be presented, including circuits in three-dimensional layouts. Finally, future directions and promising areas of research will be described.

Sun, Y.; Baca, A. J.; Ahn, J.-H.; Meitl, M.; Menard, E.; Kim, H.-S; Choi, W.; Kim, D.-H; Huang, Y.; Rogers, J. A.; Center for Nanoscale Materials; Univ. of Illinois

2008-01-01

124

Developing Flexible, High Performance Polymers with Self-Healing Capabilities  

NASA Technical Reports Server (NTRS)

Flexible, high performance polymers such as polyimides are often employed in aerospace applications. They typically find uses in areas where improved physical characteristics such as fire resistance, long term thermal stability, and solvent resistance are required. It is anticipated that such polymers could find uses in future long duration exploration missions as well. Their use would be even more advantageous if self-healing capability or mechanisms could be incorporated into these polymers. Such innovative approaches are currently being studied at the NASA Kennedy Space Center for use in high performance wiring systems or inflatable and habitation structures. Self-healing or self-sealing capability would significantly reduce maintenance requirements, and increase the safety and reliability performance of the systems into which these polymers would be incorporated. Many unique challenges need to be overcome in order to incorporate a self-healing mechanism into flexible, high performance polymers. Significant research into the incorporation of a self-healing mechanism into structural composites has been carried out over the past decade by a number of groups, notable among them being the University of I1linois [I]. Various mechanisms for the introduction of self-healing have been investigated. Examples of these are: 1) Microcapsule-based healant delivery. 2) Vascular network delivery. 3) Damage induced triggering of latent substrate properties. Successful self-healing has been demonstrated in structural epoxy systems with almost complete reestablishment of composite strength being achieved through the use of microcapsulation technology. However, the incorporation of a self-healing mechanism into a system in which the material is flexible, or a thin film, is much more challenging. In the case of using microencapsulation, healant core content must be small enough to reside in films less than 0.1 millimeters thick, and must overcome significant capillary and surface tension forces to flow, mix and react to achieve healing. Vascular networks small enough to fit into such films must also overcome these same flow limitations. Self-healing has also been demonstrated in ionomeric substrates such as Surlyn , wherein the heat generated by a projectile impact triggers the latent ability of this substrate to flow back to its original shape. Recent work using Diels-Alder reactions have shown promise in bringing about actual reforming of broken chemical bonds to achieve self-healing [2]. All self-healing mechanisms that rely on the use of inherent latent substrate properties require some degree of polymer chain flow to achieve any significant level of healing.

Jolley, Scott T.; Williams, Martha K.; Gibson, Tracy L.; Caraccio, Anne J.

2011-01-01

125

Functionality enhancement of industrialized optical fiber sensors and system developed for full-scale pavement monitoring.  

PubMed

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

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

2014-01-01

126

Sulfur-extended asphalt pavement: a three-year progress report. Final report  

SciTech Connect

This report documents post-construction performance of a sulfur-extended asphalt (SEA) pavement and a conventional pavement used as a control, monitored over a 3-year period. The SEA pavement used 30% sulfur by total weight of the binder. Both pavements were placed under New York State specifications during the summer of 1980 on Rtes 118 and 202 in Westchester County, New York. After 3 years, overall condition of both the SEA and control pavements was satisfactory. The two did not differ significantly in deflection, rutting, friction, or aggregate degradation. Data obtained from analysis of pavement cores showed that the stability of the SEA mix was equal to or higher than that of the control at all ages. Similarly, its resilient modulus was greater at all ages and temperatures. Although tensile-strength ratios measured for both mixes indicated a potential for stripping, virtually none was observed in any of the field cores for either pavement at any age.

Van Bramer, T.F.

1986-10-01

127

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

PubMed Central

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

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

2014-01-01

128

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...

129

MTG Flexible Combined Imager optical design and performances  

NASA Astrophysics Data System (ADS)

Meteosat Third Generation is the next ESA Program of Earth Observation dedicated to Nowcasting and very short term Weather Forecasting (NWC), medium/short range Global and Regional Numerical Weather Prediction (NWP), and Climate and Air Composition Monitoring. The satellites will be operating from the Geostationary orbit using a 3 axes stabilized platform. The main instrument is called the Flexible Combined Imager (FCI), currently under development by Thales Alenia Space France (TAS-F). This instrument will provide full images of the Earth every 10 minutes in 16 spectral channels between 0.44 and 13.3 ?m, with a ground resolution from 0.5 km to 2 km. The FCI is composed of a TMA telescope developed by Kayser-Threde (KT), which includes a Scan mirror, and a calibration mechanism with an embedded black body dedicated to accurate in-flight IR radiometric calibration and a Metallic Neutral density for dedicated VNIR Sun calibration. The image produced by the telescope is split into several spectral groups by a spectral separation assembly (SSA) with dichroïc beamsplitters. The output beams are collimated to ease the instrument integration, and reach the cold optics (CO-I) which focalize the optical beams onto the detectors. The cold optics and IR detectors are accurately positioned inside a common cryostat to improve registration between spectral channels. Spectral filters are integrated on top of the detectors in order to achieve the required spectral selection. This article will describe the optical design and the main optical performances of the FCI: image quality, very high line-of-sight stability, and an efficient stray-light rejection thanks to the implementation of dedicated baffles and a stringent control of contamination. The FCI currently under development is expected to exhibit a significant improvement of performances with respect to Meteosat Second Generation satellites.

Ouaknine, J.; Gode, S.; Napierala, B.; Viard, T.; Foerster, U.; Fray, S.; Peacoke, Patrick; Hartl, M.; Hallibert, P.; Durand, Y.

2013-09-01

130

Asphalt pavement surfaces and asphalt mixtures. Transportation research record  

SciTech Connect

The papers in this volume, which deal with asphalt pavement surfaces and asphalt mixtures, should be of interest to state and local construction, design, materials, and research engineers as well as contractors and material producers. The papers in Part 1 include discussions of pavement smoothness specifications and skidding characteristics. The first four papers in Part 2 were submitted in response to a call for papers for a session at the 75th Annual Meeting of the Transportation Research Board on low-temperature properties of hot-mix asphalt. The next eight are on the influence of volumetric and strength properties on the performance of hot-mix asphalt. In the following three papers, the topics covered are the complex modulus of asphalt concrete, cold in-place asphalt recycling, and polymer modification of asphalt pavements in Ontario. The last two papers were presented in a session on relationship of materials characterization to accelerated pavement performance testing.

NONE

1996-12-31

131

PERFORMANCE CONSTRAINTS ON THE MANEUVERABILITY OF FLEXIBLE AND RIGID BIOLOGICAL SYSTEMS  

Microsoft Academic Search

Flexible bodies possessed by fish and marine mammals have been shown to permit high levels of performance with respect to maneuverability. However, flexibility has been avoided in the construction of engineered vehicles. Mechanisms to enhance turning performance with rigid bodies were assessed for the whirligig beetle and the humpback whale. Whirligig beetles swim rapidly in circular patterns. Curved trajectories were

Frank E. Fish

1999-01-01

132

Platypus: Design and Implementation of a Flexible High Performance Object Store.  

E-print Network

Platypus: Design and Implementation of a Flexible High Performance Object Store. Zhen He1, Stephen. This paper reports the design and implementation of Platypus, a trans- actional object store. The twin goals of flexibility and performance dominate the design of Platypus. The design includes: support for SMP concurrency

He, Zhen

133

The performance impact of flexibility in the Stanford FLASH multiprocessor  

Microsoft Academic Search

Several multiprocessors have been proposed that offer programmable implementations of scal- able cache coherence as well as support for message passing. In the FLASH machine, flexibility is obtained by the use of a programmable node controller, called MAGIC, through which all transac- tions in a node pass. We use the actual code sequences that implement the cache coherence protocol, together

Mark Heinrich; Jeffrey S. Kuskin; David Ofelt; John Heinlein; Joel Baxter; Jaswinder Pal Singh; Richard Simoni; Kourosh Gharachorloo; David Nakahira; Mark A. Horowitz; Anoop Gupta; Mendel Rosenblum; John L. Hennessy

1994-01-01

134

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...

135

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

136

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

2012-06-07

137

International Symposium on Pavement LCA (Pavement LCA 2014) TRB Co-Sponsored  

E-print Network

International Symposium on Pavement LCA (Pavement LCA 2014) TRB Co-Sponsored (Sustainable Pavements AFD00(1)) FHWA Co-Sponsored (Sustainable Pavement Task Group) Location: UC Davis Campus Conference Assessment (LCA) for pavements. The workshop will be coordinated with activities of the FWHA Sustainable

California at Davis, University of

138

Cloud Impacts on Pavement Temperature in Energy Balance Models  

NASA Astrophysics Data System (ADS)

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

Walker, C. L.

2013-12-01

139

Pavement roughness and skid properties  

NASA Astrophysics Data System (ADS)

Road roughness and roadway safety as it relates to both surface and air transportation are discussed. The role of road roughness in vehicle ride, the measurement of roughness, the evaluation of riding confort, and the effect of grooving pavements are discussed. The effects of differential pavement friction on the response of cars in skidding maneuvers is discussed.

140

Field performance of maintenance treatments constructed with reclaimed asphalt pavement (RAP). Final research report, September 1992-August 1994  

SciTech Connect

In the study, RAP was blended with recycling emulsions and conventional maintenance mixtures in attempts to improve its field performance as a maintenance mixture. RAP was also mixed with stabilizers and used as a base material in maintenance projects. Several field experiments were constructed throughout the state, and the report documents their performance.

Estakhri, C.K.

1994-11-01

141

Summary of Concrete Overlays Existing concrete pavement  

E-print Network

Summary of Concrete Overlays Existing concrete pavement with surface distresses Prepared surface Monolithic pavement with new concrete surface Existing asphalt pavement with surface distresses Milled pavement with asphalt surface distresses Milled and cleaned surface New 2­5 in. (5.1­12.7 cm) bonded

142

Mix Type Selection for Perpetual Pavements  

Microsoft Academic Search

The notion of long-life asphalt pavements or Perpetual Pavements came about in the 1960s, although they were not recognized as such at that time. Using thick layers of HMA was seen as a way of reducing the total section thickness of the pavement. Since then, it has become apparent that this approach to design can lead to asphalt pavements that

David E. Newcomb; Kent R. Hansen

143

Combined Effect of Moving Wheel Loading and Three-Dimensional Contact Stresses on Perpetual Pavement Responses  

Microsoft Academic Search

Tire–pavement interaction was analyzed with measured three-dimensional (3-D) tire contact stresses at various load levels (35, 44, and 53 kN) and constant tire pressure (720 kPa). The combined effect of moving wheel load and 3-D contact stresses on flexible pavement response was evaluated with a developed 3-D finite element (FE) model, which incorporated the measured 3-D tire contact stresses, hot-mix

Hao Wang; Imad L. Al-Qadi

2009-01-01

144

Sensitivity of the LCA allocation procedure for BFS recycled into pavement structures  

Microsoft Academic Search

The purpose of this paper is twofold: to investigate the problems involved when performing an environmental assessment of various pavements structures and to establish the method applied to solutions proposed by official French guidelines. This assessment will be performed by employing the life cycle assessment (LCA) methodology specifically adapted to road pavements through a parametric environmental evaluation tool developed by

Shahinaz Sayagh; Anne Ventura; Tung Hoang; Denis François; Agnès Jullien

2010-01-01

145

Pavement recycling. Executive summary and report  

SciTech Connect

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

NONE

1995-10-01

146

Material-specific effects of hydrated lime on the properties and performance behavior of asphalt mixtures and asphaltic pavements  

Microsoft Academic Search

This study evaluates hydrated lime-treated hot-mix asphalt (HMA) mixtures through various laboratory tests, including the dynamic modulus test and performance tests to characterize permanent deformation and fatigue damage resistance both in displacement-controlled and force-controlled modes. Two different asphalt mixtures — the asphalt concrete mixture and the fine aggregate asphalt matrix mixture — which differ only in the amount of additional

Francisco Thiago Sacramento Aragão; Junghun Lee; Yong-Rak Kim; Pravat Karki

2010-01-01

147

Quantitative performance-based evaluation of a procedure for flexible design concept generation  

E-print Network

This thesis presents an experimental methodology for objective and quantitative design procedure evaluation based on anticipated lifecycle performance of design concepts, and a procedure for flexible design concept generation. ...

Cardin, Michel-Alexandre, 1979-

2011-01-01

148

Small-scale accelerated pavement testing  

SciTech Connect

This paper presents the results of a study conducted to explore the use of small-scale models of accelerated pavement testing (APT) devices to evaluate the performance of pavements in conjunction with full-scale tests. The motivation for the study was the availability of a model mobile load simulator (MMLS), which had been built originally to illustrate the operation of the full-scale mobile load simulator (MLS) under design at the time. The scaling requirements will be different depending on whether dynamic (inertia), viscous, or gravity effects are important. One must thus decide which one of these effects controls the behavior to try to reproduce it exactly. In the preliminary tests conducted with the MMLS, emphasis had been placed in reproducing accurately the viscoelastic behavior of the asphalt layer. The possibility of obtaining valid results, even if similitude is not maintained in relation to inertia forces, is explored in this paper. The effects of load frequency or velocity and the effects of layer thicknesses are studied. The total thickness of the model pavement, which must be finite, and its effects on displacements and strains are also considered. It is concluded that even when full similitude is not satisfied it is possible to obtain valid results that can be extrapolated to predict prototype performance if one were interested primarily in the behavior of the asphalt layer. Preliminary analyses should be conducted, however, to guide on the selection of the model dimensions.

Kim, S.M. [Korea Highway Corp., Kyunggi (Korea, Republic of). Highway Research Inst.; Hugo, F. [Univ. of Stellenbosch (South Africa). Inst. for Transport Technology; Roesset, J.M. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1998-03-01

149

Effects of flexibility on aerodynamic performance of delta wings with different sweep angles  

NASA Astrophysics Data System (ADS)

Force measurement and surface oil flow visualization experiments were conducted in a wind tunnel to investigate the effects of flexibility on aerodynamic performance of delta wings with different sweep angles. The experimental results indicate that the maximum lift coefficient is increased and the stall angle is delayed as the sweep angle increases for both rigid and flexible wings. It is also found that the maximum lift coefficients of the flexible wings with a sweep angle from 35° to 50° are higher than those of the rigid ones. The increment of the maximum lift coefficient in particular achieves 32.9% compared with the case without lift enhancement for the 40° flexible delta wing. Moreover, the surface oil flow visualization experiments show that the stall of the flexible wing of the moderate low sweep angle is accompanied by helical flow structure, while the vortex bursting appears on the corresponding rigid wing.

Liu, Yang; Zuo, Linxuan; Wang, Jinjun

2010-05-01

150

Permanent deformation and moisture susceptibility related aggregate tests for use in hot-mix asphalt pavements  

Microsoft Academic Search

This study was based on the elements of the National Cooperative Highway Research Program (NCHRP) Project 4-19 that focused on the aggregate tests related to the permanent deformation and moisture susceptibility of Hot Mix Asphalt (HMA) pavements. Five coarse and six fine aggregates were used in this research program. The effect of these aggregates on the HMA pavement performance was

Erza Rismantojo

2002-01-01

151

Correlation between the Laboratory and Field Permeability Values for the Superpave Pavements  

Microsoft Academic Search

Permeability affects the performance of Superpave pavements. Percolation of water, through the interconnected voids of an asphalt pavement, causes stripping of the asphalt-bound layer as well as deterioration of the foundation layers of the roads. In this study, laboratory and field permeability tests, based on the principles of falling head, were conducted on different Superpave mixes with 19 mm and

Aneel Gogula; Mustaque Hossain; Stefan Romanoschi; Glenn A. Fager

2003-01-01

152

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

Microsoft Academic Search

There has been concern that the legislative mandate to use waste rubber in paving applications will result in a severe environmental problem when it becomes necessary to recycle these pavements. If successful recycling is possible, the long term performance of these pavements becomes a concern. The results of this study indicate that it is possible to recycle this material. However,

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

1995-01-01

153

Flexibility effects on the control system performance of large scale robotic manipulators  

NASA Technical Reports Server (NTRS)

Structural flexibility of robotic manipulators becomes significant and limits the performance of a control system when manipulators are large structures, manipulating on large payloads, and/or operating at high speeds. The question of when a manipulator can be considered rigid or must be considered flexible is studied as a function of manipulator dynamics and task characteristics. Results are interpreted in simple quantitative forms which can be used as design and analysis tools to decide whether or not the manipulator flexibility will be a significant factor for a given task condition. The limitations imposed by the manipulator flexibility on the joint variable feedback control system performance is determined using linear and nonlinear methods. The closed loop eigenstructure behavior of finite dimensional models under joint variable feedback is studied and results are compared with the previously reported results.

Cetinkunt, Sabri; Book, Wayne J.

1990-01-01

154

Multidisciplinary structural design and optimization for performance, cost, and flexibility  

E-print Network

Reducing cost and improving performance are two key factors in structural design. In the aerospace and automotive industries, this is particularly true with respect to design criteria such as strength, stiffness, mass, ...

Nadir, William David, 1979-

2005-01-01

155

Performance, scalability, and flexibility in the RAW network router  

E-print Network

Conventional high speed Internet routers are built using custom designed microprocessors, dubbed network processors, to efficiently handle the task of packet routing. While capable of meeting the performance demanded of ...

DeGangi, Anthony M

2004-01-01

156

Thermal Insulation Performance of Flexible Piping for Use in HTS Power Cables  

NASA Technical Reports Server (NTRS)

High-temperature superconducting (HTS) cables that typically operate at temperatures below 80 K are being developed for power transmission. The practical application of HTS power cables will require the use of flexible piping to contain the cable and the liquid nitrogen coolant. A study of thermal performance of multilayer insulation (MLI) was conducted in geometries representing both rigid and flexible piping. This experimental study performed at the Cryogenics Test Laboratory of NASA Kennedy Space Center provides a framework for the development of cost-effective, efficient thermal insulation systems that will support these long-distance flexible lines containing HTS power cables. The overall thermal performance of the insulation system for a rigid configuration and for a flexible configuration, simulating a flexible HTS power cable, was determined by the steady-state liquid nitrogen boiloff method under the full range of vacuum levels. Two different cylindrically rolled material systems were tested: a standard MLI and a layered composite insulation (LCI). Comparisons of ideal MLI, MLI on rigid piping, and MLI between flexible piping are presented.

Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

2001-01-01

157

Thermal Performance of Composite Flexible Blanket Insulations for Hypersonic Aerospace Vehicles  

NASA Technical Reports Server (NTRS)

This paper describes the thermal performance of a Composite Flexible Blanket Insulation (C.F.B.I.) considered for potential use as a thermal protection system or thermal insulation for future hypersonic vehicles such as the National Aerospace Plane (N.A.S.P.). Thermophysical properties for these insulations were also measured including the thermal conductivity at various temperatures and pressures and the emissivity of the fabrics used in the flexible insulations. The thermal response of these materials subjected to aeroconvective heating from a plasma arc is also described. Materials tested included two surface variations of the insulations, and similar insulations coated with a Protective Ceramic Coating (P.C.C.). Surface and backface temperatures were measured in the flexible insulations and on Fibrous Refractory Composite Insulation (F.R.C.I.) used as a calibration model. The uncoated flexible insulations exhibited good thermal performance up to 35 W/sq cm. The use of a P.C.C. to protect these insulations at higher heating rates is described. The results from a computerized thermal analysis model describing thermal response of those materials subjected to the plasma arc conditions are included. Thermal and optical properties were determined including thermal conductivity for the rigid and flexible insulations and emissivity for the insulation fabrics. These properties were utilized to calculate the thermal performance of the rigid and flexible insulations at the maximum heating rate.

Kourtides, Demetrius A.

1993-01-01

158

ROBUST CONTROL DESIGN OF A HIGH PERFORMANCE FLEXIBLE ELECTROMECHANICAL SYSTEM  

E-print Network

controllers applied to a Compact Disc mechanism. The design objective is to achieve good track performance control systems. In contrast to such systems, small actuator drives such as compact disc and hard­10, respectively. #12; 5 3. THE COMPACT DISC MECHANISM A Compact Disc player is an optical decoding device

Massachusetts at Amherst, University of

159

Improving a pavement-watering method on the basis1 of pavement surface temperature measurements2  

E-print Network

Improving a pavement-watering method on the basis1 of pavement surface temperature measurements2.hendel@paris.fr)8 Abstract: Pavement-watering has been studied since the 1990's and is currently considered a9 water resource availability problems require that water consumption be optimized. Although11 pavement

Paris-Sud XI, Université de

160

High performance of a solid-state flexible asymmetric supercapacitor based on graphene films.  

PubMed

Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO(2)-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H(2)SO(4) electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg(-1)) and power density (6.8 kW g(-1)), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g(-1) with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability. PMID:22751863

Choi, Bong Gill; Chang, Sung-Jin; Kang, Hyun-Wook; Park, Chan Pil; Kim, Hae Jin; Hong, Won Hi; Lee, SangGap; Huh, Yun Suk

2012-08-21

161

High Performance Fibers Based on Rigid and Flexible Polymers  

Microsoft Academic Search

This chapter covers recent developments in the production of well established high performance fibers such as Kevlar, PBO, Spectra and Dyneema fibers and depicts a new super strong M5. The latter fibers have the modulus of 330GPa and tenacity of 5GPa. DuPont de Nemours is currently developing commercial M5 fibers and yarns. A very interesting monomer namely, 2,5?dihydroxyterephthalic is used

Mehdi Afshari; Doetze J. Sikkema; Katelyn Lee; Mary Bogle

2008-01-01

162

Effect of wing inertia on hovering performance of flexible flapping wings Bo Yin and Haoxiang Luoa  

E-print Network

Effect of wing inertia on hovering performance of flexible flapping wings Bo Yin and Haoxiang Luoa in flight typically deform under the combined aerodynamic force and wing inertia; whichever is dominant inertia makes in the aerodynamic performance of the deformable wing, a two-dimensional numerical study

Luo, Haoxiang

163

Investigation of factors affecting asphalt pavement recycling and asphalt compatibility  

SciTech Connect

Both economic and environmental factors dictate that asphalt pavement be recycled. Many recycling projects have been completed using a variety of recycling additives, but little work has been done on the physiochemical aspects of pavement recycling. The present exploratory study was undertaken to better define the physiochemical variables of recycling. Objectives of the present study include: (1) to determine if molecular structuring in the asphalt binder could be observed in oxidized (air-aged) asphalt-aggregate briquets, and if so, how was structuring affected during briquits, and if so, how was structuring affected during briquet recycling and (2) to determine if recycling agents penetrate the strongly adsorbed asphalt layer on the aggregate surface. Differences were seen in asphalt component compatibility as judged by the state of peptization parameters. In extreme cases the values of the parameters correlated with properties of asphalts of known compatibility; however, a relationship between the parameters determined on a series of asphalts in pavements was not established. The parameters might be useful in evaluating additives for pavement recycling; however, more systems need to be studied to fully assess their potential usefulness. Finally, the parameters need to be correlated with performance-related measurements such as asphalt rheological and mix properties. Examination of the parameters and their changes on asphalt oxidative aging may also be informative with regard to asphalt durability inasmuch as oxidation-induced changes are a major cause of asphalt pavement failure.

Venable, R.L.; Petersen, J.C.; Robertson, R.E.; Plancher, H.

1983-03-01

164

GEOLOGICAL NOTE Desert Pavement: An Environmental Canary?  

E-print Network

GEOLOGICAL NOTE Desert Pavement: An Environmental Canary? P K. Haft Division of Earth and Ocean 27708 Ie-mail: /wff@geo.duke_eciul ABSTRACT Ongoing ctisruption of ancient, varnished desert pavement that the pavement disturbances reported here ~ue rarc on the millcnnhll time scale of desert varnish format ion

Ahmad, Sajjad

165

Impact of pavement conditions on crash severity.  

PubMed

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

Li, Yingfeng; Liu, Chunxiao; Ding, Liang

2013-10-01

166

Overview of the Arizona Quiet Pavement Program  

Microsoft Academic Search

The Arizona Quiet Pavement Pilot Program (QP3) was initially implemented to reduce highway related traffic noise by overlaying most of the Phoenix metropolitan area Portland cement concrete pavement with a one inch thick asphalt rubber friction coarse. With FHWA support, this program represents the first time that pavement surface type has been allowed as a noise mitigation strategy on federally

Paul Donavan; Larry Scofield

2005-01-01

167

Effect of flexibility of wing on aerodynamic performance in plunge motion  

NASA Astrophysics Data System (ADS)

The improvement of aerodynamic performance in plunge motion is investigated through a flexibility of chordwise and spanwise directions by applied a prescribed deformation on a airfoil at Reynolds number of 30000. The aerodynamic performance of flapping motion can be evaluated through a thrust force, a input power and a propulsive efficiency which is a ratio of propulsive power which generate from thrust force to input power. Unsteady viscous flows over NACA 0012 airfoils in plunge motions are computed by using a time-accurate preconditioned Navier-Stokes solver coupled with a volume grid deformation code. For spanwise or chordwise flexibility, there is a optimal phase angle for maximum thrust force and propulsive efficiency. Especially, a combination of spanwise and chordwise flexibility can improve aerodynamic performance higher than that of adding increment from each of flexibility. Compared with rigid motion, 10% deformation in chordwise and spanwise directions with zero phase angle can enhance the thrust force coefficient from 0.22 to 0.38 and 0.54 respectively, while thrust force coefficient is 0.8 by combination of spanwise and chordwise flexibility.

Le, Tuyen Quang; Ko, Jin Hwan; Park, Soo Hyung; Byun, Doyoung

2009-11-01

168

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

169

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

170

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

171

Location, Marketing, and the Financial Flexibility of Nonprofit Performing Arts Organizations in Second Tier Cities  

Microsoft Academic Search

This article examines the effect of location relative to other marketing factors on the financial flexibility of nonprofit performing arts organizations (PAOs). While product development and promotional and pricing strategies are important marketing factors, locational advantages have become an important strategic asset for the arts industry. Yet very little research has been done on the locational dimensions of this industry.

Christine A. Lai; Jessie P. H. Poon

2009-01-01

172

The tribology of flexible magnetic recording media—the influence of wear on signal performance  

Microsoft Academic Search

The tribology of magnetic recording systems is different to conventional tribology in many important aspects and an understanding of this branch of the science is still in its infancy. This paper presents a review of one specific aspect of the tribology of flexible tape storage systems, that is wear of heads and media and the effect on signal performance. Based

J. L. Sullivan

1998-01-01

173

Manufacturing and Performance Assessments of Several Applications of Electrotextiles and Large-Area Flexible Circuits  

Microsoft Academic Search

Numerous applications of electrotextiles and flexible circuits have been identified that can advance systems performance for many commercial, military, and aerospace devices. Several novel uses of electrotextiles have been developed for lab testing, while others have been utilized in products on the commercial market, as well as items that have flown in space. ILC Dover, Inc. has utilized conductive fibers

David P. Cadogan; Lauren S. Shook

174

Towards a new generation of mission planning systems: Flexibility and performance  

NASA Technical Reports Server (NTRS)

This paper presents some new approaches which are required for a better adequacy of Mission Planning Systems. In particular, the performance flexibility and genericity issues are discussed based on experience acquired through various Mission Planning systems developed by Matra Marconi Space.

Gasquet, A.; Parrod, Y.; Desaintvincent, A.

1994-01-01

175

The Open Runtime Platform: A Flexible High-Performance Managed Runtime Environment  

Microsoft Academic Search

The Open Runtime Platform (ORP) is a high-performance managed runtime environment (MRTE) that features exact generational garbage collection, fast thread synchronization, and multiple coexisting just-in-time compilers (JITs). ORP was designed for flexibility in order to support experiments in dynamic compilation, garbage collection, synchronization, and other technologies. It can be built to run either Java ? or

Michal Cierniak; M arsha Eng; Neal Glew; James Stichnoth

2003-01-01

176

HR flexibility and firm performance: analysis of a multi-level causal model  

Microsoft Academic Search

Human resource flexibility as a construct, how it develops, and its effect on firm performance have not received adequate attention in strategic HRM literature in spite of their obvious importance in today's dynamic competitive environment. Based on a study of 98 manufacturing and 103 service firms in India, this paper addresses these issues by developing and testing a multi-level model

Sumita Ketkar; P. K. Sett

2009-01-01

177

Pavement roughness on expansive clays  

E-print Network

PAVEMENT ROUGHI'JESS ON EXPANSIVE CLAYS A Thesis by Manuel Oli van Velasco Submitted to the Graduate College Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1980 Major Subject...: Civil Engineerina PAVEMENT ROUGHNESS ON EXPANSIVE CLAYS A Thesis by Manuel Olivan Velasco Approved as to style and content by: R t L. L ton ? Chairm Wayne A. nlap - Member Luis F. Costa - Member ames F. Slowey - Member Donald McDonald - Head...

Velasco, Manuel O

2012-06-07

178

Transferable self-welding silver nanowire network as high performance transparent flexible electrode  

NASA Astrophysics Data System (ADS)

High performance transparent electrodes (TEs) with figures-of-merit as high as 471 were assembled using ultralong silver nanowires (Ag NWs). A room-temperature plasma was employed to enhance the conductivity of the Ag NW TEs by simultaneously removing the insulating PVP layer coating on the NWs and welding the junctions tightly. Furthermore, we developed a general way to fabricate TEs regardless of substrate limitations by transferring the as-fabricated Ag NW network onto various substrates directly, and the transmittance can remain as high as 91% with a sheet resistivity of 13 ?/sq. The highly robust and stable flexible TEs will have broad applications in flexible optoelectronic and electronic devices.

Zhu, Siwei; Gao, Yuan; Hu, Bin; Li, Jia; Su, Jun; Fan, Zhiyong; Zhou, Jun

2013-08-01

179

California DOT 1. Briefly summarize your current pavement smoothness requirements.  

E-print Network

California DOT 1. Briefly summarize your current pavement smoothness requirements. For HMA pavement to OGFC placed on existing pavement not constructed under the same project. If concrete pavement is placed ordered. 39-1.12B Straightedge The top layer of HMA pavement must not vary from the lower edge of a12-foot

180

Guide Specification for Highway Construction Texturing Concrete Pavement for  

E-print Network

Guide Specification for Highway Construction Texturing Concrete Pavement for Reduced Tire/Pavement Noise using Diamond Grinding Designation: CPSCP GS 1-11 (rev 3/1/2011) National Concrete Pavement for Highway Construction Texturing Concrete Pavement for Reduced Tire/Pavement Noise using Diamond Grinding

181

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

182

Review of permeable pavement systems  

Microsoft Academic Search

The purpose of this review paper is to summarise the wide-range but diffuse literature on predominantly permeable pavement systems (PPS), highlight current trends in research and industry, and to recommend future areas of research and development. The development of PPS as an integral part of sustainable drainage systems is reviewed in the context of traditional and modern urban drainage. Particular

Miklas Scholz; Piotr Grabowiecki

2007-01-01

183

Nondestructive Evaluation of Pavements Ultrasonic  

E-print Network

Nondestructive Evaluation of Pavements Ð Ultrasonic Tomography Kyle Hoegh, Graduate Student Dr. Lev:// pavementndt.weebly.com #12;Outline ·! Ultrasonic Tomography Overview ·! Georgia Example ·! MnROAD ­!Joint.weebly.com #12;Ultrasonic Methods: Pros and Cons ·! Advantages ­! Multiple applications ·! Thickness

Minnesota, University of

184

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 pavements, and PCC Pavements are all included in this special provision. http

185

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

Code of Federal Regulations, 2010 CFR

...survey that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information including...analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance...

2010-04-01

186

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

Code of Federal Regulations, 2011 CFR

...survey that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information including...analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance...

2011-04-01

187

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

Code of Federal Regulations, 2010 CFR

...that includes roughness, distress, rutting, and surface friction (as appropriate); (iv) Traffic information including...that includes roughness, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance...

2010-04-01

188

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

Code of Federal Regulations, 2011 CFR

...survey that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information including...analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance...

2011-04-01

189

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

Code of Federal Regulations, 2012 CFR

...survey that includes ride, distress, rutting, and surface friction (as appropriate); (iv) Traffic information including...analysis that includes ride, distress, rutting, and surface friction (as appropriate); (ii) A pavement performance...

2012-04-01

190

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

E-print Network

changes during the different modes of aging processes. Unaged asphalts meeting the same specifications can show drastic differences in field performance under the same pavement conditions, as borne out by many field tests (10, 30, 54). Several... changes during the different modes of aging processes. Unaged asphalts meeting the same specifications can show drastic differences in field performance under the same pavement conditions, as borne out by many field tests (10, 30, 54). Several...

Lau, Chee Keung

2012-06-07

191

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

192

Preliminary evaluation of LTPP continuously reinforced concrete (CRC) pavement test sections. Final report, February 1995--October 1998  

SciTech Connect

As part of the study reported here, analysis of data from the LTPP GPS-5 test sections was conducted to identify factors that influence long-term crack spacing in continuously reinforced concrete (CRC) pavements and to determine that effect of crack spacing on pavement performance. Data from the 85 test sections from the GPS-5 experiment were analyzed.

Tayabji, S.D.; Selezneva, O.; Jiang, Y.J.

1999-07-01

193

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

194

Rutting and drainage design methodology for a concrete block pavement  

E-print Network

Concrete block pavements (CBP) have historically been hics. used in low trafficked applications as an alternative to asphalt and concrete pavement because of their aesthetic quality. However, concrete block pavements have not been used for high...

Poduska, Daryl Jason

2012-06-07

195

Pervious Pavement A Strategic Plan For NYC DOT  

E-print Network

Pervious Pavement A Strategic Plan For NYC DOT Presented By: Rene Brana Spring 2012 Capstone: Pervious Pavement - A Strategic Plan for NYC DOT 2 Capstone: Pervious Pavement - A Strategic Plan for NYC DOT 3 Image courtesy of

Qian, Ning

196

Acute effects of different volumes of dynamic stretching on vertical jump performance, flexibility and muscular endurance.  

PubMed

The purpose of this study was to examine the acute effects of different volumes of a dynamic stretching routine on vertical jump (VJ) performance, flexibility and muscular endurance (ME). Twenty-six males (age 22·2 ± 1·3 years) performed three separate randomized conditions: (i) a control (CON) condition (5-min jog + 12 min of resting), (ii) a 5-min jog + a dynamic stretching routine (DS1; 6·7 ± 1·3 min) and (iii) a 5-min jog + a dynamic stretching routine with twice the volume (DS2; 12·1 ± 1·6 min). The dynamic stretching routine included 11 exercises targeting the hip and thigh musculature. VJ performance (jump height and velocity) and flexibility were measured prior to and following all conditions, while ME was measured following all conditions. The DS1 and DS2 conditions increased VJ height and velocity (P<0·01), while the CON condition did not change (P>0·05). When compared to the CON condition, the DS1 condition did not improve ME (P>0·05), whereas the DS2 condition resulted in a significant (15·6%) decrease in the number of repetitions completed (P<0·05). Flexibility increased following all conditions (P<0·01), while the DS1 condition was significantly greater (P<0·01) than the CON condition at post-testing. These results suggest that dynamic stretching routines lasting approximately 6-12 min performed following a 5-min jog resulted in similar increases in VJ performance and flexibility. However, longer durations of dynamic stretching routines may impair repetitive high-intensity activities. PMID:24438386

Ryan, Eric D; Everett, Kenneth L; Smith, Doug B; Pollner, Christie; Thompson, Brennan J; Sobolewski, Eric J; Fiddler, Ryan E

2014-11-01

197

A flexible and inexpensive high-performance auditory evoked response recording system appropriate for research purposes.  

PubMed

Recording auditory evoked responses (AER) is done not only in hospitals and clinics worldwide to detect hearing impairments and estimate hearing thresholds, but also in research centers to understand and model the mechanisms involved in the process of hearing. This paper describes a high-performance, flexible, and inexpensive AER recording system. A full description of the hardware and software modules that compose the AER recording system is provided. The performance of this system was evaluated by conducting five experiments with both real and artificially synthesized auditory brainstem response and middle latency response signals at different intensity levels and stimulation rates. The results indicate that the flexibility of the described system is appropriate to record AER signals under several recording conditions. The AER recording system described in this article is a flexible and inexpensive high-performance AER recording system. This recording system also incorporates a platform through which users are allowed to implement advanced signal processing methods. Moreover, its manufacturing cost is significantly lower than that of other commercially available alternatives. These advantages may prove useful in many research applications in audiology. PMID:24870606

Valderrama, Joaquin T; de la Torre, Angel; Alvarez, Isaac; Segura, Jose Carlos; Sainz, Manuel; Vargas, Jose Luis

2014-10-01

198

Exploring pavement crack evaluation with bidimensional empirical mode decomposition  

NASA Astrophysics Data System (ADS)

Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD), a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decomposition (EMD), which can decompose non-linear and non-stationary signals into basis functions called intrinsic mode functions (IMF). IMFs are monocomponent functions that have well defined instantaneous frequencies. EMD is a sifting process that is non-parametric and data-driven; it does not depend on an a priori basis set. It is able to remove noise from signals without complicated convolution processes. BEMD decomposes an image into two-dimensional IMFs. The present paper explores pavement crack detection using BEMD together with the Sobel edge detector. A number of images are filtered with BEMD to remove noise, and the residual image analyzed with the Sobel edge detector for crack detection. The results are compared with results from the Canny edge detector, which uses a Gaussian filter for image smoothing before performing edge detection. The objective is to qualitatively explore how well BEMD is able to smooth an image for more effective and speedier edge detection with the Sobel method.

Ayenu-Prah, Albert; Attoh-Okine, Nii

2007-04-01

199

Markovian & Weibull Approach to Concrete Pavement Monitoring  

E-print Network

­ Impervious Concrete Pavement 402 kPa 583 kPa 779 kPa #12;#12;Skid Resistance 0 10 20 30 40 50 60 70 4-Jun-09Markovian & Weibull Approach to Concrete Pavement Monitoring Bernard Igbafen Izevbekhai, P.E., Ph) Sensor Location (mm) MnROAD Cell 85 : Pervious Concrete Pavement 393 kPa 574 kPa 789 kPa 0 20 40 60 80

Minnesota, University of

200

High Performance, Robust Control of Flexible Space Structures: MSFC Center Director's Discretionary Fund  

NASA Technical Reports Server (NTRS)

Many spacecraft systems have ambitious objectives that place stringent requirements on control systems. Achievable performance is often limited because of difficulty of obtaining accurate models for flexible space structures. To achieve sufficiently high performance to accomplish mission objectives may require the ability to refine the control design model based on closed-loop test data and tune the controller based on the refined model. A control system design procedure is developed based on mixed H2/H(infinity) optimization to synthesize a set of controllers explicitly trading between nominal performance and robust stability. A homotopy algorithm is presented which generates a trajectory of gains that may be implemented to determine maximum achievable performance for a given model error bound. Examples show that a better balance between robustness and performance is obtained using the mixed H2/H(infinity) design method than either H2 or mu-synthesis control design. A second contribution is a new procedure for closed-loop system identification which refines parameters of a control design model in a canonical realization. Examples demonstrate convergence of the parameter estimation and improved performance realized by using the refined model for controller redesign. These developments result in an effective mechanism for achieving high-performance control of flexible space structures.

Whorton, M. S.

1998-01-01

201

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

202

The sports performance application of vibration exercise for warm-up, flexibility and sprint speed.  

PubMed

Since the turn of the 21st century, there has been a resurgence of vibration technology to enhance sport science especially for power and force development. However, vibration exercise has been trialled in other areas that are central to athlete performance such as warm-up, flexibility and sprint speed. Therefore, the aim of this review was to attempt to gain a better understanding of how acute and short-term vibration exercise may impact on warm-up, flexibility and sprint speed. The importance of warming up for sporting performance has been well documented and vibration exercise has the capability to be included or used as a standalone warm-up modality to increase intramuscular temperature at a faster rate compared to other conventional warm-up modalities. However, vibration exercise does not provide any additional neurogenic benefits compared to conventional dynamic and passive warm-up interventions. Vibration exercise appears to be a safe modality that does not produce any adverse affects causing injury or harm and could be used during interval and substitution breaks, as it would incur a low metabolic cost and be time-efficient compared to conventional warm-up modalities. Acute or short-term vibration exercise can enhance flexibility and range of motion without having a detrimental effect on muscle power, however it is less clear which mechanisms may be responsible for this enhancement. It appears that vibration exercise is not capable of improving sprint speed performance; this could be due to the complex and dynamic nature of sprinting where the purported increase in muscle power from vibration exercise is probably lost on repeated actions of high force generation. Vibration exercise is a safe modality that produces no adverse side effects for injury or harm. It has the time-efficient capability of providing coaches, trainers, and exercise specialists with an alternative modality that can be implemented for warm-up and flexibility either in isolation or in conjunction with other conventional training methods. PMID:23679142

Cochrane, Darryl

2013-01-01

203

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

204

The flexible Ca-test: An improved performance in a gas permeability measurement system  

NASA Astrophysics Data System (ADS)

A flexible performance permeability measuring test for flexible organic light-emitting diodes is described in this paper. A single thin film layer of gas barriers is constructed on polyethersulfone (PES). The barrier coats the upper and lower surfaces of the PES layer. Two PES samples, one coated with Al2O3 on both surfaces and the other coated on a single surface, were made for comparison. According to this test, the time-dependent transmission curve of the one sided barrier sample had a linear slope which measured 1.65 g/m2/day at room temperature at a 50% relative humidity. This result shows that the measurement time is about 182% faster than has been achieved with the conventional test structure that uses a glass substrate. In addition, this measurement structure not only reduces the inevitable electrical noise which occurs during measurement but also increases the water vapor permeation signal. These effects improve the sensing reliability of the test. In addition, this structure is flexible, so one can instantly detect barrier performance changes when applying external stress.

Song, Eun Ho; Park, Young Wook; Choi, Jin Hwan; Park, Tae Hyun; Jeong, Jin Wook; Choi, Hyun Ju; Ju, Byeong Kwon

2011-05-01

205

The evaluation of airfield pavements  

E-print Network

for the multiple-wheel assembly, because the stress patterns do not over- lap appreciably at shallow depths, ? Wheel Load -- ? ? Pavement Base Pressure Distribution ? Subgrade Figure 2. Distribution of Pressure Produced by a Single Wheel Load ? Thin... loading conditions. It is an accepted theorem of the engineering profession that the value and accuracy of a test procedure is directly related to how well the test corresponds to field conditions. It is easily seen that bearing values obtained...

Poor, Arthur Reginald

2012-06-07

206

Provider performance measures in private and public programs: achieving meaningful alignment with flexibility to innovate.  

PubMed

In recent years there has been a significant expansion in the use of provider performance measures for quality improvement, payment, and public reporting. Using data from a survey of health plans, we characterize the use of such performance measures by private payers. We also compare the use of these measures among selected private and public programs. We studied twenty-three health plans with 121 million commercial enrollees--66 percent of the national commercial enrollment. The health plans reported using 546 distinct performance measures. There was much variation in the use of performance measures in both private and public payment and care delivery programs, despite common areas of focus that included cardiovascular conditions, diabetes, and preventive services. We conclude that policy makers and stakeholders who seek less variability in the use of performance measures to increase consistency should balance this goal with the need for flexibility to meet the needs of specific populations and promote innovation. PMID:23918491

Higgins, Aparna; Veselovskiy, German; McKown, Lauren

2013-08-01

207

Enhanced hydrodynamic performance of flexible fins using macro fiber composite actuators  

NASA Astrophysics Data System (ADS)

Recent studies on the role of body flexibility in propulsion suggest that fish have the ability to control the shape or modulate the stiffness of the fins for optimized performance. Inspired by nature’s ability to modulate stiffness and shape for different operating conditions, this paper investigates active control of flapping foils for thrust tailoring using Macro Fiber Composites (MFCs). A coupled piezohydroelastic model has been developed to predict the propulsive performance of an actively deforming fin. The effect of important parameters such as oscillation frequency, flexibility of the fin, applied voltage and the phase difference between applied voltage and heaving on propulsive performance are studied and reported. It is observed that distributed actuation along fin produces maximum performance through proper selection of the phase difference between heaving and voltage. The optimal phase for lower values of fin stiffness is approximately 90° and it approaches 0° for higher stiffness values. Experiments performed to determine the effect of active control using MFCs validate the theoretical results.

Kancharala, A. K.; Philen, M. K.

2014-10-01

208

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

209

A systematic investigation of polymer binder flexibility on the electrode performance of lithium-ion batteries.  

PubMed

The mechanical failure at the electrode interfaces (laminate/current collector and binder/particle interfaces) leads to particle isolation and delamination, which has been regarded as one of the main reasons for the capacity decay and cell failure of lithium-ion batteries (LIBs). Polymer binder provides the key function for a good interface property and for maintaining the electrode integrity of LIBs. Triethylene glycol monomethyl ether (TEG) moieties were incorporated into polymethacrylic acid (PMAA) to different extents at the molecular level. Microscratch tests of the graphite electrodes based on these binders indicate that the electrode is more flexible with 5 or 10% TEG in the polymer binders. Crack generation is inhibited by the flexible TEG-containing binder, compared to that of the unmodified PMAA-based electrode, leading to the better cycling performance of the flexible electrode. With a 10% TEG moiety in the binder, the graphite half-cell reaches a reversible capacity of >270 mAh/g at the 1C rate, compared to a value of ?190 mAh/g for the unmodified PMAA binder. PMID:25203598

Yuca, Neslihan; Zhao, Hui; Song, Xiangyun; Dogdu, Murat Ferhat; Yuan, Wen; Fu, Yanbao; Battaglia, Vincent S; Xiao, Xingcheng; Liu, Gao

2014-10-01

210

Graphene/carbon black hybrid film for flexible and high rate performance supercapacitor  

NASA Astrophysics Data System (ADS)

Reduced graphene oxide/carbon black (rGO/CB) hybrid films with different carbon black (CB) contents are prepared by a simple vacuum filtration method. The CB particles evenly distribute between the graphene layers, not only preventing the compact restack of rGO sheets but also providing electrical contact between the base planes of rGO sheets. As expected, the as-prepared rGO/CB hybrid film shows enhanced rate capability when compared with rGO film. Furthermore, a solid-state flexible supercapacitor has been constructed with the optimized rGO/CB hybrid film by using polyvinyl alcohol (PVA)/H2SO4 gel as electrolyte and Au coated PET film as current collector and mechanical support. The solid-state flexible supercapacitor shows a specific capacitance of 112 F g-1 at a scan rate of 5 mV s-1, and excellent rate performance with a specific capacitance of 79.6 F g-1 at a high scan rate of 1 V s-1. Moreover, the flexible solid-state supercapacitor exhibits good cycling stability with capacitance retention of 94% after 3000 cycles in normal state plus 2000 cycles in bent state.

Wang, Yaming; Chen, Junchen; Cao, Jianyun; Liu, Yan; Zhou, Yu; Ouyang, Jia-Hu; Jia, Dechang

2014-12-01

211

Study of flexible fin and compliant joint stiffness on propulsive performance: theory and experiments.  

PubMed

The caudal fin is a major source of thrust generation in fish locomotion. Along with the fin stiffness, the stiffness of the joint connecting the fish body to the tail plays a major role in the generation of thrust. This paper investigates the combined effect of fin and joint flexibility on propulsive performance using theoretical and experimental studies. For this study, fluid-structure interaction of the fin has been modeled using the 2D unsteady panel method coupled with nonlinear Euler-Bernoulli beam theory. The compliant joint has been modeled as a torsional spring at the leading edge of the fin. A comparison of self-propelled speed and efficiency with parameters such as heaving and pitching amplitude, oscillation frequency, flexibility of the fin and the compliant joint is reported. The model also predicts the optimized stiffnesses of the compliant joint and the fin for maximum efficiency. Experiments have been carried out to determine the effect of fin and joint stiffness on propulsive performance. Digital image correlation has been used to measure the deformation of the fins and the measured deformation is coupled with the hydrodynamic model to predict the performance. The predicted theoretical performance behavior closely matches the experimental values. PMID:24737004

Kancharala, A K; Philen, M K

2014-09-01

212

Highway pavement distress evaluation: Modeling measurement error  

Microsoft Academic Search

There has been a proliferation of inspection technologies to quantify distresses on highway pavement systems. These technologies employ varying measurement principles and are subject to measurement errors. Estimates of measurement errors are therefore required in order to select among these techniques, and to get accurate assessments of pavement condition. There is abundant literature concerning techniques available for the numerical study

Frannie Humplick

1992-01-01

213

Fractionation of heavy metals in pavement runoff  

Microsoft Academic Search

Abstract The transport of anthropogenic constituents by runoff from urban roadways can adversely impact the quality of adjacent receiving waters and soils. Metal elements are the most,persistent constituents found in pavement,runoff. A section of urban highway pavement in Cincinnati, Ohio, USA with an average daily traffic count of 150 000 vehicles was instrumented to sample lateral sheet flow from the

John J. Sansalone; Steven G. Buchberger; Souhail R. Al-abed

1996-01-01

214

STONE PAVEMENTS IN DESERTS! RONALD U. COOKE  

E-print Network

STONE PAVEMENTS IN DESERTS! RONALD U. COOKE ABSTRACT. Stone pavenlents are armored surfaces compnsing intricate mosaics of coarse particles, usually only one or two stones thick, set on or in fine processes, nlay vary greatly from place to place. STONE pavements are defined as armored surfaces comprising

Ahmad, Sajjad

215

Concrete Pavement Sustainability Sustainability Track Leadership  

E-print Network

#12;What Else is Happening? · FHWA advocating "Green Paving" technologies ­ Recycled concrete, twoTrack 13: Concrete Pavement Sustainability #12;Sustainability Track Leadership Committee Members package for concrete pavement sustainability (initiated1/10) · A conference on sustainability of concrete

216

Terra Flexible Blanket Solar Array Deployment, On-Orbit Performance and Future Applications  

NASA Technical Reports Server (NTRS)

The Terra spacecraft (formerly identified as EOS AM1) is the flagship in a planned series of NASA/GSFC (Goddard Space Flight Center) Earth observing system satellites designed to provide information on the health of the Earth's land, oceans, air, ice, and life as a total ecological global system. It has been successfully performing its mission since a late-December 1999 launch into a 705 km polar orbit. The spacecraft is powered by a single wing, flexible blanket array using single junction (SJ) gallium arsenide/germanium (GaAs/Ge) solar cells sized to provide five year end-of-life (EOL) power of greater than 5000 watts at 127 volts. It is currently the highest voltage and power operational flexible blanket array with GaAs/Ge cells. This paper briefly describes the wing design as a basis for discussing the operation of the electronics and mechanisms used to achieve successful on-orbit deployment. Its orbital electrical performance to date will be presented and compared to analytical predictions based on ground qualification testing. The paper concludes with a brief section on future applications and performance trends using advanced multi-junction cells and weight-efficient mechanical components. A viewgraph presentation is attached that outlines the same information as the paper and includes more images of the Terra Spacecraft and its components.

Kurland, Richard; Schurig, Hans; Rosenfeld, Mark; Herriage, Michael; Gaddy, Edward; Keys, Denney; Faust, Carl; Andiario, William; Kurtz, Michelle; Moyer, Eric; Day, John H. (Technical Monitor)

2000-01-01

217

Terra Flexible Blanket Solar Array Deployment, On-Orbit Performance and Future Applications  

NASA Technical Reports Server (NTRS)

The Terra spacecraft (formerly identified as EOS AM1) is the flagship in a planned series of NASA/GSFC (Goddard Space Flight Center) Earth observing system satellites designed to provide information on the health of the Earth's land, oceans, air, ice, and life as a total ecological global system. It has been successfully performing its mission since a late-December 1999 launch into a 705 km polar orbit. The spacecraft is powered by a single wing, flexible blanket array using single junction (SJ) gallium arsenide/germanium (GaAs/Ge) solar cells sized to provide five year end-of-life (EOL) power of greater than 5000 watts at 127 volts. It is currently the highest voltage and power operational flexible blanket array with GaAs/Ge cells. This paper briefly describes the wing design as a basis for discussing the operation of the electronics and mechanisms used to achieve successful on-orbit deployment. Its orbital electrical performance to date will be presented and compared to analytical predictions based on ground qualification testing. The paper concludes with a brief section on future applications and performance trends using advanced multi-junction cells and weight-efficient mechanical components.

Kurland, Richard; Schurig, Hans; Rosenfeld, Mark; Herriage, Michael; Gaddy, Edward; Keys, Denney; Faust, Carl; Andiario, William; Kurtz, Michelle; Moyer, Eric; Day, John H. (Technical Monitor)

2000-01-01

218

New Developments in the Debate on Pavement-Vehicle  

E-print Network

New Developments in the Debate on Pavement-Vehicle Interaction: The Impact of Pavement Design aerodynamics Improve energy efficiency Reduce rolling resistance, including pavement-vehicle interaction #12 standards for big trucks" February 18, 2014 What about fuel efficiency standards for pavements? #12;Slide 5

de Weck, Olivier L.

219

RESEARCH Open Access Pavement crack characteristic detection based  

E-print Network

RESEARCH Open Access Pavement crack characteristic detection based on sparse representation Xiaoming Sun1 , Jianping Huang1 , Wanyu Liu1* and Mantao Xu2 Abstract Pavement crack detection plays an important role in pavement maintaining and management. The three- dimensional (3D) pavement crack detection

Joensuu, University of

220

TEXAS PAVEMENT PRESERVATION CENTER FOUR-YEAR SUMMARY REPORT  

E-print Network

TEXAS PAVEMENT PRESERVATION CENTER FOUR-YEAR SUMMARY REPORT Dr. Yetkin Yildirim, P.E., TPPC Director E-mail: yetkin@mail.utexas.edu Mailing address: Texas Pavement Preservation Center Center................................................................................................ 100 #12;#12;TEXAS PAVEMENT PRESERVATION CENTER (TPPC) About the Center The Texas Pavement Preservation

Texas at Austin, University of

221

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

Code of Federal Regulations, 2010 CFR

... Federal lands pavement management system (PMS). In addition...the AASHTO's “Pavement Management Guide.” 1 1 “Pavement Management Guide,” AASHTO...nature of the transportation network. These different...

2010-04-01

222

Road Materials and Pavements Design. Volume X No X/2009, pages 1 to 16 Pavement Design for Curved Road Sections  

E-print Network

Road Materials and Pavements Design. Volume X ­ No X/2009, pages 1 to 16 Pavement Design for Curved pavements Christophe Petit* -- Malick Diakhaté* -- Anne Millien* -- Annabelle Phelipot-Mardelé* -- Bertrand@eurovia.com ABSTRACT. This paper focuses on damage processes other than the main one observed and studied in pavement

Paris-Sud XI, Université de

223

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

224

Use of scrap rubber in asphalt pavement surfaces. Special report  

SciTech Connect

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

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

1991-12-01

225

User's guide: Hot-mix recycling of asphalt concrete pavements  

NASA Astrophysics Data System (ADS)

This guide provides the technical information required to implement the application of hot-mix recycling of asphalt concrete pavements. Included are details on application, benefits/advantages, limitations/disadvantages, and costs associated with this technology. Information is provided on three demonstration sites at Fort Gillem, Georgia; Fort Leavenworth, Kansas; and Fort Benjamin Harrison, Indiana. Also provided is information concerning funding, procurement, maintenance, and performance monitoring. A fact sheet on recycling, contract specification example, and references are provided in the appendices.

Shoenberger, James E.

1993-05-01

226

User's guide: Hot-mix recycling of asphalt concrete pavements  

Microsoft Academic Search

This guide provides the technical information required to implement the application of hot-mix recycling of asphalt concrete pavements. Included are details on application, benefits\\/advantages, limitations\\/disadvantages, and costs associated with this technology. Information is provided on three demonstration sites at Fort Gillem, Georgia; Fort Leavenworth, Kansas; and Fort Benjamin Harrison, Indiana. Also provided is information concerning funding, procurement, maintenance, and performance

James E. Shoenberger

1993-01-01

227

Flexible Pillared Graphene-Paper Electrodes for High-Performance Electrochemical Supercapacitors  

SciTech Connect

Flexible graphene paper (GP) pillared by carbon black (CB) nanoparticles using a simple vacuum filtration method is developed as a high-performance electrode material for supercapacitors. Through the introduction of CB nanoparticles as spacers, the self-restacking of graphene sheets during the filtration process is mitigated to a great extent. The pillared GP-based supercapacitors exhibit excellent electrochemical performances and cyclic stabilities compared with GP without the addition of CB nanoparticles. At a scan rate of 10 mV s?1, the specific capacitance of the pillared GP is 138 F g^?1 and 83.2 F g^?1 with negligible 3.85% and 4.35% capacitance degradation after 2000 cycles in aqueous and organic electrolytes, respectively. At an extremely fast scan rate of 500 mV s ^?1, the specific capacitance can reach 80 F g^?1 in aqueous electrolyte. No binder is needed for assembling the supercapacitor cells and the pillared GP itself may serve as a current collector due to its intrinsic high electrical conductivity. The pillared GP has great potential in the development of promising flexible and ultralight-weight supercapacitors for electrochemical energy storage.

Wang, Gongkai; Sun, Xiang; Lu, Fengyuan; Sun, Hongtao; Yu, Mingpeng; Jiang, Weilin; Liu, Changsheng; Lian, Jie

2012-02-09

228

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

229

Scalable fabrication of high-performance and flexible graphene strain sensors  

NASA Astrophysics Data System (ADS)

Graphene strain sensors have promising prospects of applications in detecting human motion. However, the shortage of graphene growth and patterning techniques has become a challenging issue hindering the application of graphene strain sensors. Therefore, we propose wafer-scale flexible strain sensors with high-performance, which can be fabricated in one-step laser scribing. The graphene films could be obtained by directly reducing graphene oxide film in a Light-Scribe DVD burner. The gauge factor (GF) of the graphene strain sensor (10 mm × 10 mm square) is 0.11. In order to enhance the GF further, graphene micro-ribbons (20 ?m width, 0.6 mm long) has been used as strain sensors, of which the GF is up to 9.49. The devices may conform to various application requirements, such as high GF for low-strain applications and low GF for high deformation applications. The work indicates that laser scribed flexible graphene strain sensors could be widely used in medical-sensing, bio-sensing, artificial skin and many other areas.Graphene strain sensors have promising prospects of applications in detecting human motion. However, the shortage of graphene growth and patterning techniques has become a challenging issue hindering the application of graphene strain sensors. Therefore, we propose wafer-scale flexible strain sensors with high-performance, which can be fabricated in one-step laser scribing. The graphene films could be obtained by directly reducing graphene oxide film in a Light-Scribe DVD burner. The gauge factor (GF) of the graphene strain sensor (10 mm × 10 mm square) is 0.11. In order to enhance the GF further, graphene micro-ribbons (20 ?m width, 0.6 mm long) has been used as strain sensors, of which the GF is up to 9.49. The devices may conform to various application requirements, such as high GF for low-strain applications and low GF for high deformation applications. The work indicates that laser scribed flexible graphene strain sensors could be widely used in medical-sensing, bio-sensing, artificial skin and many other areas. Electronic supplementary information (ESI) available: Testing results and discussion of graphene strain sensors. See DOI: 10.1039/c3nr04521h

Tian, He; Shu, Yi; Cui, Ya-Long; Mi, Wen-Tian; Yang, Yi; Xie, Dan; Ren, Tian-Ling

2013-12-01

230

Performance limitations of joint variable-feedback controllers due to manipulator structural flexibility  

NASA Technical Reports Server (NTRS)

The performance limitations of manipulators under joint variable-feedback control are studied as a function of the mechanical flexibility inherent in the manipulator structure. A finite-dimensional time-domain dynamic model of a two-link two-joint planar manipulator is used in the study. Emphasis is placed on determining the limitations of control algorithms that use only joint variable-feedback information in calculations of control decisions, since most motion control systems in practice are of this kind. Both fine and gross motion cases are studied. Results for fine motion agree well with previously reported results in the literature and are also helpful in explaining the performance limitations in fast gross motions.

Cetinkunt, Sabri; Book, Wayne J.

1990-01-01

231

A quantitative performance measure for a clinical evaluation of comb structure removal algorithms in flexible endoscopy  

NASA Astrophysics Data System (ADS)

Modern techniques for technical inspection as well as medical diagnostics and therapy in keyhole-surgery scenarios make use of flexible endoscopes. Common to both application fields are very small natural or manmade entry points to the observed scene, as well as the complexity of the hollow itself. These make the use of rigid lens-based endoscopes or tip chip videoscopes impossible. Due to the fact that the fiber-optic image guide of a flexible endoscope introduces a comb structure to the acquired images, many research has been devoted to algorithms for an effective removal of such artifacts. Oftentimes, this research has been motivated by the fact, that the comb structure prevents an application of some well-established methods offered by the computer vision and image processing community. Unfortunately, the performance of the presented approaches are commonly visually evaluated or with respect to proprietary, non-standardized metrics. Thus, the performances of individual algorithms are hard to compare with each other. For this reasons, we propose a performance measure for fiber-optic imaging devices that has been motivated by the physics of optics. In this field, an optical system is frequently described by linear systems theory and the system's quality can be expressed by its transfer function. The determination of this transfer function has been standardized by the ISO for lens based imaging systems and represents a widely accepted measure for the quality of such systems. In this contribution, we present methods that account for fiber-optic imaging systems and thus enable a standardized performance evaluation. Finally, we demonstrate its use by comparing two recent state of the art comb structure removal algorithms, each of them being a representative of a spatial and a frequency domain method, respectively.

Rupp, Stephan

2008-03-01

232

Fabrication of high-performance flexible alkaline batteries by implementing multiwalled carbon nanotubes and copolymer separator.  

PubMed

A flexible alkaline battery with multiwalled carbon nanotube (MWCNT) enhanced composite electrodes and polyvinyl alcohol (PVA)-poly (acrylic acid) (PAA) copolymer separator has been developed. Purified MWCNTs appear to be the most effective conductive additive, while the flexible copolymer separator not only enhances flexibility but also serves as electrolyte storage. PMID:24510667

Wang, Zhiqian; Wu, Zheqiong; Bramnik, Natalia; Mitra, Somenath

2014-02-12

233

High-performance logic circuits using solution-based, low-temperature semiconductors for flexible electronics  

NASA Astrophysics Data System (ADS)

In this work we demonstrate high performance and low-power n-type inverters using solution-based CdS as the semiconductor in thin film transistors. Our fabrication process consists of five mask levels and a maximum temperature of 150 °C. The CdS is deposited using chemical bath deposition at 70 °C to provide full compatibility with flexible substrates. Isolated TFTs showed mobilities up to 10 cm2/V-s and threshold voltages of approximately 0.5V. Inverters were biased at 1, 3 and 5 V, resulting in maximum gains in the range of 60 at VDD = 3V. The devices and circuits are fully patterned using standard photolithographic techniques that can be used to design more complex circuitry for flexible and large area electronic applications. In addition we used an extraction parameter method for our TFTs that allows the use of regular SPICE simulation software to design and test the circuits. Our simulations are in good agreement with the experimental data for isolated devices and inverters. Other circuits such as NAND gates are also demonstrated.

Mejia, Israel; Salas-Villasenor, Ana L.; Murphy, John W.; Kunnen, George R.; Cantley, Kurtis D.; Allee, David R.; Gnade, Bruce E.; Quevedo-Lopez, Manuel A.

2013-05-01

234

Scalable fabrication of high-performance and flexible graphene strain sensors.  

PubMed

Graphene strain sensors have promising prospects of applications in detecting human motion. However, the shortage of graphene growth and patterning techniques has become a challenging issue hindering the application of graphene strain sensors. Therefore, we propose wafer-scale flexible strain sensors with high-performance, which can be fabricated in one-step laser scribing. The graphene films could be obtained by directly reducing graphene oxide film in a Light-Scribe DVD burner. The gauge factor (GF) of the graphene strain sensor (10 mm × 10 mm square) is 0.11. In order to enhance the GF further, graphene micro-ribbons (20 ?m width, 0.6 mm long) has been used as strain sensors, of which the GF is up to 9.49. The devices may conform to various application requirements, such as high GF for low-strain applications and low GF for high deformation applications. The work indicates that laser scribed flexible graphene strain sensors could be widely used in medical-sensing, bio-sensing, artificial skin and many other areas. PMID:24281713

Tian, He; Shu, Yi; Cui, Ya-Long; Mi, Wen-Tian; Yang, Yi; Xie, Dan; Ren, Tian-Ling

2014-01-21

235

High performance low temperature carbon composite catalysts for flexible dye sensitized solar cells.  

PubMed

Roll-to-roll manufacturing of dye sensitized solar cells (DSSCs) requires efficient and low cost materials that adhere well on the flexible substrates used. In this regard, different low temperature carbon composite counter electrode (CE) catalyst ink formulations for flexible DSSCs were developed that can be simply and quickly coated on plastic substrates and dried below 150 °C. The CEs were investigated in terms of photovoltaic performance in DSSCs by current-voltage measurements, mechanical adhesion properties by bending and tape tests, electro-catalytic performance by electrochemical impedance spectroscopy and microstructure by electron microscopy. In the bending and tape tests, PEDOT-carbon composite catalyst layers exhibited higher elasticity and better adhesion on all the studied substrates (ITO-PET and ITO-PEN plastic, and FTO-glass), compared to a binder free carbon composite and a TiO2 binder enriched carbon composite, and showed lower charge transfer resistance (1.5-3 ? cm(2)) than the traditional thermally platinized CE (5 ? cm(2)), demonstrating better catalytic performance for the tri-iodide reduction reaction. Also the TiO2 binder enriched carbon composite showed good catalytic characteristics and relatively good adhesion on ITO-PET, but on ITO-PEN its adhesion was poor. A DSSC with the TiO2 binder enriched catalyst layer reached 85% of the solar energy conversion efficiency of the reference DSSC based on the traditional thermally platinized CE. Based on the aforementioned characteristics, these carbon composites are promising candidates for replacing the platinum catalyst in a high volume roll-to-roll manufacturing process of DSSCs. PMID:24042582

Hashmi, Syed Ghufran; Halme, Janne; Saukkonen, Tapio; Rautama, Eeva-Leena; Lund, Peter

2013-10-28

236

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

Code of Federal Regulations, 2010 CFR

... Federal lands pavement management system (PMS). In addition...the AASHTO's “Pavement Management Guide.”2 2 “Pavement Management Guide,” AASHTO...the nature of the pavement network. These different...

2010-04-01

237

Influence of landing gear flexibility on aircraft performance during ground roll  

NASA Technical Reports Server (NTRS)

An analysis is made of the influence of landing gear deflection characteristics on aircraft performance on the ground up to rotation. A quasi-steady dynamic equilibrium state is assumed, including other simplifying assumptions such as calm air conditions and normal aircraft lift and drag. Ground incidence is defined as the angle made by the mean aerodynamic chord of the wing with respect to the ground plane, and equations are given for force and balance which determine the quasi-equilibrium conditions for the aircraft during ground roll. Results indicate that the landing gear deflections lead to a substantial increase in the angle of attack, and the variation in the ground incidence due to landing gear flexibility could be as much as + or - 50%, and the reduction in tail load requirements almost 25%.

Sivaramakrishnan, M. M.

1981-01-01

238

Path planning for machine vision assisted, teleoperated pavement crack sealer  

SciTech Connect

During the last few years, several teleoperated and machine-vision-assisted systems have been developed in construction and maintenance areas such as pavement crack sealing, sewer pipe rehabilitation, excavation, surface finishing, and materials handling. This paper presents a path-planning algorithm used for a machine-vision-assisted automatic pavement crack sealing system. In general, path planning is an important task for optimal motion of a robot whether its environment is structured or unstructured. Manual path planning is not always possible or desirable. A simple greedy path algorithm is utilized for optimal motion of the automated pavement crack sealer. Some unique and broadly applicable computational tools and data structures are required to implement the algorithm in a digital image domain. These components are described, then the performance of the algorithm is compared with the implicit manual path plans of system operators. The comparison is based on computational cost versus overall gains in crack-sealing-process efficiency. Applications of this work in teleoperation, graphical control, and other infrastructure maintenance areas are also suggested.

Kim, Y.S.; Haas, C.T.; Greer, R. [Univ. of Texas, Austin, TX (United States)

1998-03-01

239

Long Term Monitoring of Moisture Under Pavements.  

National Technical Information Service (NTIS)

Monitoring of the environmental instrumentation installed under select pavement sections constructed by the Ohio Department of Transportation (ODOT) in 1995 on US 23 in Delaware County, Ohio was continued. The measurements made consisted of soil moisture,...

J. Howdyshell, T. Butalia, W. Wolfe

2010-01-01

240

Innovations in Pavement Recycling Session CTS Conference  

E-print Network

of rehabilitation #12;#12;Obliterating existing pavement distresses & joints #12;Grid roller #12;Pneumatic & smooth drains "! New CL culverts !! Grade corrections !! Over 80,000 SY of pcc rubblized in 7 days #12

Minnesota, University of

241

Permeable Pavements, Green Roofs, and Cisterns  

E-print Network

asphalt and concrete, which are completely impervious surfaces. Permeable pavements allow water site features, reduc- monplace throughout North Carolina, ing and disconnecting impervious cover concrete, pervious asphalt, permeable interlocking concrete pavers (PICPs), concrete grid pavers

Hunt, William F.

242

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 pavements. In this model, oxygen transport and reaction were described mathematically as two interlinked steps: 1) diffusion and/or flow of oxygen from the atmosphere above the pavement into the interconnected air voids in the pavement; and 2) diffusion...

Han, Rongbin

2012-07-16

243

Guidelines and specifications for the use of reclaimed aggregates in pavement. Final report  

SciTech Connect

The project focused on evaluating the performance of recycled concrete for use as a base material under hot mix asphalt pavements and as an aggregate in Portland cement concrete pavements. In order to meet this objective, several goals were established. First, published literature on RCA was reviewed and a survey of State Highway Agencies (SHA) was performed to determine the extent of use of RCA in highway projects. Second, the RCA was tested at the FDOT Material Lab in Gainesville, Florida, to determine the material properties. Third, by using the output from the falling weight deflectometer test along with the KENSLABS and KENLAYER computer programs (Huang, 1993), a theoretical analysis was performed to predict the number of repetitions before the pavements failed in both the fatigue and permanent deformation criteria. Lastly, nine design sections involving HMA and PCC pavements were constructed at the University of Central Florida`s Circular Accelerated Test Track (UCF-CATT) to evaluate the response of the pavement sections made with RCA under actual dual-wheel loading.

Chini, S.A.; Kuo, S.S.; Duxbury, J.P.; Monteiro, F.M.B.R.; Mbwambo, W.J.

1998-08-01

244

PCC Pavement Sustainability in New York Economy, Environment, and Society: 2 Out of 3 is Easy  

E-print Network

PCC Pavement Sustainability in New York Economy, Environment, and Society: 2 Out of 3 is Easy Bill PCC pavement sustainability strategy. NYSDOT recognizes that PCC pavements have "sustainable efforts, begging the question, "Is any pavement truly "sustainable?"" 1. PCC pavements, and pavement

245

Incorporating inspection decisions in pavement management  

Microsoft Academic Search

Pavement management systems need to address not only maintenance and rehabilitation (M&R) decisions, but also facility inspection decisions. The state of the art in pavement management is lacking of any consistent methodology for making such decisions on a cost-effectiveness basis. Such a methodology must recognize the presence of interactions between M&R and inspection decisions. These interactions argue for a joint

Samer Madanat

1993-01-01

246

Automatic inspection of pavement cracking distress  

Microsoft Academic Search

We present an image processing algorithm customized for high-speed, real-time inspection of pavement cracking. In the algorithm, a pavement image is divided into grid cells of 8×8 pixels, and each cell is classified as a noncrack or crack cell using the grayscale information of the border pixels. Whether a crack cell can be regarded as a basic element (or seed)

Yaxiong Huang; Bugao Xu

2006-01-01

247

Lithium-doped zinc oxide nanowires-polymer composite for high performance flexible piezoelectric nanogenerator.  

PubMed

We present a method to develop high performance flexible piezoelectric nanogenerators (NGs) by employing Li-doped ZnO nanowires (NWs). We synthesized Li-doped ZnO NWs and adopted them to replace intrinsic ZnO NWs with a relatively low piezoelectric coefficient. When we exploited the ferroelectric phase transition induced in Li-doped ZnO NWs, the performance of the NGs was significantly improved and the NG fabrication process was greatly simplified. In addition, our approach can be easily expanded for large-scale NG fabrication. Consequently, the NGs fabricated by our simple method exhibit the excelling output voltage and current, which are stable and reproducible during periodic bending/releasing measurement over extended cycles. In addition, output voltage and current up to ?180 V and ?50 ?A, respectively, were obtained in the large-scale NG. The approach introduced here extends the performance limits of ZnO-based NGs and their potentials in practical applications. PMID:25265473

Shin, Sung-Ho; Kim, Young-Hwan; Lee, Min Hyung; Jung, Joo-Yun; Seol, Jae Hun; Nah, Junghyo

2014-10-28

248

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

249

Printable nanostructured silicon solar cells for high-performance, large-area flexible photovoltaics.  

PubMed

Nanostructured forms of crystalline silicon represent an attractive materials building block for photovoltaics due to their potential benefits to significantly reduce the consumption of active materials, relax the requirement of materials purity for high performance, and hence achieve greatly improved levelized cost of energy. Despite successful demonstrations for their concepts over the past decade, however, the practical application of nanostructured silicon solar cells for large-scale implementation has been hampered by many existing challenges associated with the consumption of the entire wafer or expensive source materials, difficulties to precisely control materials properties and doping characteristics, or restrictions on substrate materials and scalability. Here we present a highly integrable materials platform of nanostructured silicon solar cells that can overcome these limitations. Ultrathin silicon solar microcells integrated with engineered photonic nanostructures are fabricated directly from wafer-based source materials in configurations that can lower the materials cost and can be compatible with deterministic assembly procedures to allow programmable, large-scale distribution, unlimited choices of module substrates, as well as lightweight, mechanically compliant constructions. Systematic studies on optical and electrical properties, photovoltaic performance in experiments, as well as numerical modeling elucidate important design rules for nanoscale photon management with ultrathin, nanostructured silicon solar cells and their interconnected, mechanically flexible modules, where we demonstrate 12.4% solar-to-electric energy conversion efficiency for printed ultrathin (?8 ?m) nanostructured silicon solar cells when configured with near-optimal designs of rear-surface nanoposts, antireflection coating, and back-surface reflector. PMID:25272244

Lee, Sung-Min; Biswas, Roshni; Li, Weigu; Kang, Dongseok; Chan, Lesley; Yoon, Jongseung

2014-10-28

250

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

251

Hemispherically aggregated BaTiO3 nanoparticle composite thin film for high-performance flexible piezoelectric nanogenerator.  

PubMed

We report high-performance flexible nanogenerators (NGs) based on a composite thin film, composed of hemispherically aggregated BaTiO3 nanoparticles (NPs) and poly(vinylidene fluoride-co-hexafluoropropene) P(VDF-HFP). The hemispherical BTO-P(VDF-HFP) clusters were realized by a solvent evaporation method, which greatly enhanced piezoelectric power generation. The flexible NGs exhibit high electrical output up to ?75 V and ?15 ?A at the applied force normal to the surface, indicating the important role of hemispherical BTO clusters. Besides, the durability and reproducibility of the NGs were tested by cyclic measurement under bending stage, generating the output of ?5 V and ?750 nA. The approach we introduce here is simple, cost-effective, and well-suited for large-scale high-performance flexible NG fabrication. PMID:24517314

Shin, Sung-Ho; Kim, Young-Hwan; Lee, Min Hyung; Jung, Joo-Yun; Nah, Junghyo

2014-03-25

252

Anionic polymer electrolyte with enhanced electrochemical performance based on surface-charged latex nanoparticles for flexible lithium-ion batteries  

NASA Astrophysics Data System (ADS)

In the present paper, an anionic polymer electrolyte (APE) is facilely prepared using the surface-charged latex nanoparticles as the building blocks for the flexible lithium-ion batteries. Driven by the self-assembly of surface-charged latex, the APE demonstrates nanoporous structure, which provides continuous pathway for lithium conduction. The anionic polymer membrane exhibits mechanical flexibility before and after swollen with liquid electrolyte. Performance benefits of the anionic polymer membrane, as compared to commercialized polyethylene (PE) separator, are elucidated in terms of thermal shrinkage, liquid electrolyte wettability, mechanical bendability and open circuit voltage (OCV). Based on comprehensive characterization of the anionic polymer membrane/electrolyte characteristics, feasibility of applying the APE to electrolytes for flexible lithium-ion batteries is explored. The well-developed ion-conductive channel of the APE, in conjunction with stability of the surface-charged nanoparticles during cycling, plays a crucial role in providing excellent in cell performance.

Ma, Xianguo; Huang, Xinglan; Gao, Jiandong; Zhang, Shu; Peng, Zuling; Deng, Zhenghua; Suo, Jishuan

2014-12-01

253

Layer equivalency factors and deformation characteristics of flexible pavements  

E-print Network

stress of first stress invar1ant (8 = a& + a + a3), 2 ps i Kl K2 KI K2 exper1 mental test constants Russ1an E uation The Russ1an equation is the nickname of a deflect1on equation which 1s based on an approx1mate elastic theory. Th1s theory uses a 24... stress of first stress invar1ant (8 = a& + a + a3), 2 ps i Kl K2 KI K2 exper1 mental test constants Russ1an E uation The Russ1an equation is the nickname of a deflect1on equation which 1s based on an approx1mate elastic theory. Th1s theory uses a 24...

Hung, Jung-Tsann

2012-06-07

254

A sensitivity analysis of the Texas flexible pavement system  

E-print Network

. stab. )Granular Base Thick. 12/10 6/6 ESAL 20E6 4E6 Pl Subgrade 10 Subgrade Modulus 7000 psi 18000 psi Surface Thickness 3. 5" 2. 0' Shoulder Type Paved Unpaved AC Type (Base} AC 20 AC 10 % Voids/% AC (Base) 5/7 7/4 Granular Base Mod Wus 60, 000... BASE 10 YR. ASPH STAB BASE 1 YR, ASPH STAB BASE 10 YR ASPH/GRN BASE 1 YR, ASPH/GRN BASE 10 YR, 7 6 5 4 3 2 1 0 1 2 3 'I 5 6 CqAC/EP AqEA ( 1OP Sy. 1 OALHART Figure 4: Cracked Area Comparison Between Location and Time. GRANULAR BASE 1 YR...

Henry, Claude Patrick

2012-06-07

255

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 ...

256

Biofuel production system with operation flexibility: Evaluation of economic and environmental performance under external disturbance  

NASA Astrophysics Data System (ADS)

Biomass derived liquid hydrocarbon fuel (biofuel) has been accepted as an effective way to mitigate the reliance on petroleum and reduce the greenhouse gas emissions. An increasing demand for second generation biofuels, produced from ligno-cellulosic feedstock and compatible with current infrastructure and vehicle technologies, addresses two major challenges faced by the current US transportation sector: energy security and global warming. However, biofuel production is subject to internal disturbances (feedstock supply and commodity market) and external factors (energy market). The biofuel industry has also heavily relied on government subsidy during the early development stages. In this dissertation, I investigate how to improve the economic and environmental performance of biorefineries (and biofuel plant), as well as enhance its survivability under the external disturbances. Three types of disturbance are considered: (1) energy market fluctuation, (2) subsidy policy uncertainty, and (3) extreme weather conditions. All three factors are basically volatile, dynamic, and even unpredictable, which makes them difficult to model and have been largely ignored to date. Instead, biofuel industry and biofuel research are intensively focused on improving feedstock conversion efficiency and capital cost efficiency while assuming these advancements alone will successfully generate higher profit and thus foster the biofuel industry. The collapse of the largest corn ethanol biofuel company, Verasun Energy, in 2008 calls into question this efficiency-driven approach. A detailed analysis has revealed that although the corn ethanol plants operated by Verasun adopted the more efficient (i.e. higher ethanol yield per bushel of corn and lower capital cost) dry-mill technology, they could not maintain a fair profit margin under fluctuating market condition which made ethanol production unprofitable. This is because dry-mill plant converts a single type of biomass feedstock (corn grain) into a single primary product (ethanol). The traditional lower efficient (i.e. lower ethanol yield per bushel of corn and higher capital cost) wet-mill plant has a more diverse and adjustable product portfolio i.e. corn syrup, starch, and ethanol. The fact that only the dry-mill corn ethanol plants have bankrupted while the wet-mill corn ethanol plants have survived the late 2000s economy recession suggests that the higher conversion efficiency achieved by the dry-mill production mode has jeopardized operational flexibility, a design operational feature I agree that is indispensable for the biofuel plant's long term profit and viability. Based on the analysis of corn ethanol production, operational flexibility has been proposed as a key strategy for the next generation biofuel plants to improve its lifetime economic performance, as well as to enhance its survivability under external disturbances. This strategy requires the biofuel plant to adopt a flexible feedstock management, making it possible to utilize alternative types of biomass feedstock when the primary feedstock supply is disturbed. Biofuel plants also need to produce a wider range of final products that could meet the preference variation that either comes from the energy market or from the subsidy policy. Aspen Plus model based numerical simulations have been carried out for a thermochemical ethanol plant and a Fischer Tropsch plant (both are assumed to be located in southwest Indiana) to test this strategy under the external disturbances of extreme weather impact, different energy price projections and various subsidy policy combinations. For the thermochemical ethanol plant, effects of extreme weather conditions are mainly evaluated. It has been shown that this strategy could effectively increase the net present value of the biofuel plant and significantly decrease the GHG emission comparing with the traditional single-feedstock strategy, when the extreme weather conditions are considered. It has also been demonstrated that this strategy could significantly decrease the possibility for the bio

Kou, Nannan

257

'Bucky gel' of multiwalled carbon nanotubes as electrodes for high performance, flexible electric double layer capacitors.  

PubMed

We report the preparation of a gelled form of multiwalled carbon nanotubes (MWCNTs) with an ionic liquid 1-butyl-1-methyl pyrrolidinium bis(trifluoromethane sulfonyl)imide (BMPTFSI)), referred to as 'bucky gel', to be used as binderless electrodes in electrical double layer capacitors (EDLCs). The characteristics of gelled MWCNTs are compared with pristine MWCNTs using transmission electron microscopy, x-ray diffraction and Raman studies. A gel polymer electrolyte film consisting of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) and BMPTFSI, exhibiting a room temperature ionic conductivity of 1.5 × 10(-3) S cm(-1), shows its suitability as an electrolyte/separator in flexible EDLCs. The performance of EDLCs, assembled with bucky gel electrodes, using impedance spectroscopy, cyclic voltammetry and charge-discharge analyses, are compared with those fabricated with pristine MWCNT-electrodes. An improvement in specific capacitance (from 19.6 to 51.3 F g(-1)) is noted when pristine MWCNTs are replaced by gelled MWCNT-binderless electrodes. Although the rate performance of the EDLCs with gelled MWCNT-electrodes is reduced, the pulse power of the device is sufficiently high (~10.5 kW kg(-1)). The gelled electrodes offer improvements in energy and power densities from 2.8 to 8.0 Wh kg(-1) and 2.0 to 4.7 kW kg(-1), respectively. Studies indicate that the gel formation of MWCNTs with ionic liquid is an excellent route to obtain high-performance EDLCs. PMID:24157648

Singh, Manoj K; Kumar, Yogesh; Hashmi, S A

2013-11-22

258

Improved performance of flexible amorphous silicon solar cells with silver nanowires  

NASA Astrophysics Data System (ADS)

A novel hybrid electrode structure using Ag nanowires (NWs) to create surface plasmons to enhance light trapping is designed and applied on the front surface of hydrogenated amorphous silicon (a-Si:H) solar cells on steel substrates, targeting broad-band absorption enhancements. Ag NWs were synthesized using a soft and self-seeding process. The produced Ag NWs were deposited on indium tin oxide (ITO) glass substrates or the ITO layers of the as-prepared flexible a-Si:H solar cells to form Ag NW-ITO hybrid electrodes. The Ag NW-ITO hybrid electrodes were optimized to achieve maximum optical enhancement using surface plasmons and obtain good electrical contacts in cells. Finite-element electromagnetic simulations confirmed that the presence of the Ag NWs resulted in increased electromagnetic fields within the a-Si:H layer. Compared to the cell with conventional ITO electrode, the measured quantum efficiency of the best performing a-Si:H cell shows an obvious enhancement in the wavelength range from 330 nm to 600 nm. The cell based on the optimized Ag NW-ITO demonstrates an increase about 4% in short-circuit current density and over 6% in power conversion efficiency under AM 1.5 illumination.

Chen, Y. R.; Li, Z. Q.; Chen, X. H.; Liu, C.; Ye, X. J.; Wang, Z. B.; Sun, Z.; Huang, S. M.

2012-12-01

259

Three-dimensional hierarchical GeSe2 nanostructures for high performance flexible all-solid-state supercapacitors.  

PubMed

Highly flexible stacked and in-plane all-solid-state supercapacitors are fabricated on 3D hierarchical GeSe2 nanostructures with high performance, and, when configured as a self-powered photodetector nanosystem, can be used to power CdSe nanowire photodetectors. PMID:23180449

Wang, Xianfu; Liu, Bin; Wang, Qiufan; Song, Weifeng; Hou, Xiaojuan; Chen, Di; Cheng, Yi-bing; Shen, Guozhen

2013-03-13

260

Guide to Cement-Based Integrated Pavement Solutions  

E-print Network

Guide to Cement-Based Integrated Pavement Solutions August 2011 #12;Cement-Based Integrated Pavement Solutions Heavy Industrial Airports Highways Country Roads Arterials Commercial Commercial Residential Recreation LAND USE CEMENT-BASED INTEGRATED PAVEMENT SOLUTIONS 1 2 3 4 5 6 7 8

261

Fast Error Estimates For Indirect Measurements: Applications To Pavement Engineering  

E-print Network

Fast Error Estimates For Indirect Measurements: Applications To Pavement Engineering Carlos that is difficult to measure directly (e.g., lifetime of a pavement, efficiency of an engine, etc). To estimate y computation time. As an example of this methodology, we give pavement lifetime estimates. This work

Kreinovich, Vladik

262

Research Article Automatic Road Pavement Assessment with Image Processing: Review  

E-print Network

Research Article Automatic Road Pavement Assessment with Image Processing: Review and Comparison describe the proposed method to detect fine defects in pavement surface. This approach is based on a multi for evaluating this difficult task ­ the road pavement crack detection ­ is introduced. Finally, the proposed

Boyer, Edmond

263

Wisconsin DOT 1. Briefly summarize your current pavement smoothness requirements.  

E-print Network

Wisconsin DOT 1. Briefly summarize your current pavement smoothness requirements. We currently-contact profiling equipment. Most PCC pavements are profiled using lightweight profilers when the project is still closed to traffic. Most HMA pavements are profiled using high speed profilers (with the same measuring

264

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally  

E-print Network

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded � Verification � Concluding Remarks Part � II (Companion presentation) � Asphalt Pavements � Effect of Aging: Asphalt concrete pavements (Part II) E1 E2 E3 Eh 1 2 3 h #12;Graded Finite Elements Graded Elements

Paulino, Glaucio H.

265

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 Center Office of Pavement Technology at Iowa State University 400 7th Street AW 2711 South Loop Drive

266

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally  

E-print Network

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded � II � Asphalt Pavements � Effect of Aging � Simulations � Concluding Remarks #12;3 Objectives Develop) Correspondence Principle based formulation Application: Asphalt concrete pavements (Part II) #12;4 Asphalt

Paulino, Glaucio H.

267

TWO LIFT PCC PAVEMENTS TO MEET PUBLIC NEEDS  

E-print Network

TWO LIFT PCC PAVEMENTS TO MEET PUBLIC NEEDS TWO LIFT PCC PAVEMENTS TO MEETTWO LIFT PCC PAVEMENTS99PTEC99 EUROPEAN EXPERIENCEEUROPEAN EXPERIENCEEUROPEAN EXPERIENCE Countries employing two lift paving ­ France, Germany and Austria Lessons learned - 2-5.5 inch high quality surface courses - 8

268

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR)  

E-print Network

deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavementPAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating

Shan, Jie

269

Highly conductive and flexible polymer composites with improved mechanical and electromagnetic interference shielding performances.  

PubMed

New flexible and conductive materials (FCMs) comprising a quartz fiber cloth (QFC) reinforced multi-walled carbon nanotubes (MWCNTs)-carbon aerogel (QMCA) and poly(dimethylsiloxane) (PDMS) have been successfully prepared. The QMCA-PDMS composite with a very low loading of MWCNTs (?1.6 wt%) demonstrates enhanced performance in tensile strength (129.6 MPa), modulus (3.41 GPa) and electromagnetic interference (EMI) shielding efficiency (SE) (?16 dB in X-band (8.2-12.4 GHz) region). Compared to the QC (where MWCNTs were simply deposited on the QFCs without forming aerogel networks) based PDMS composite, a ?120%, 330% and 178% increase of tensile strength, modulus, and EMI SE was obtained, respectively. Moreover, the EMI SE of the QMCA-PDMS composite can further reach 20 dB (a SE level needed for commercial applications) with only 2 wt% MWCNTs. Furthermore, the conductivity of the QMCA-PDMS laminate can reach 1.67 S cm(-1) even with very low MWCNTs (1.6 wt%), which still remains constant even after 5000 times bending and exhibits an increase of ?170% than that of MWCNT-carbon aerogel (MCA)-PDMS at 20% strain. Such intriguing performances are mainly attributed to their unique networks in QMCA-PDMS composites. In addition, these features can also protect electronics against harm from external forces and EMI, giving the brand-new FCMs huge potential in next-generation devices, like E-skin, robot joints and so on. PMID:24577052

Chen, Mengting; Zhang, Ling; Duan, Shasha; Jing, Shilong; Jiang, Hao; Luo, Meifang; Li, Chunzhong

2014-04-01

270

Evaluation of non-metallic fiber reinforced concrete in new full depth pcc pavements. Final report  

SciTech Connect

This final report presents the construction and performance evaluation of a new full depth pavement, constructed with a new type non-metallic fiber reinforced concrete (NMFRC). The mixture proportions used, the quality control tests conducted for the evaluation of the fresh and hardened concrete properties, the procedure used for mixing, transporting, placing, consolidating, finishing, and curing of the concrete are described. Periodic inspection of the full depth pavement was done and this report includes the results of these inspections. The feasibility of using this NMFRC in the construction of highway structures has been discussed. The new NMFRC with enhanced fatigue, impact resistance, modulus of rupture, ductility and toughness properties is suitable for the construction of full depth pavements. However, a life-cycle cost analysis shows that NMFRC is not a favorable choice, because of it`s high initial cost.

Ramakrishnan, V.; Tolmare, N.S.

1998-12-30

271

Spills on Flat Inclined Pavements  

SciTech Connect

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

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

2004-03-01

272

Influence of bending mode shape and trailing edge deflection on propulsive performance of flexible heaving fins using digital image correlation  

NASA Astrophysics Data System (ADS)

The propulsive performance of flexible flapping fins greatly depends on the stiffness of the fins along with the oscillating parameters. The bending mode shape and trailing edge deflection of the oscillating fins play a major role in the generation of thrust and efficiency. This paper examines the deformation pattern of heaving flexible foils and its dependency on propulsive performance. Experimental investigation has been carried out on fins of various lengths oscillating at their leading edge. A LaVision 2D/3D StrainMaster Digital Image Correlation (DIC) system was used to measure the deformation of the fins. It is observed that the propulsive performance can be maximized by operating at frequencies close to resonance. Trailing edge amplitude and deformation pattern together play an important role in achieving high propulsive performance even when the oscillation frequency is not close to resonant frequency.

Kancharala, Ashok K.; Dewillie, Kevin; Philen, Michael K.

2014-03-01

273

User's guide: Cold-mix recycling of asphalt concrete pavements. Final report  

SciTech Connect

This guide provides the technical information required to implement the application of cold-mix recycling of asphalt concrete pavements. Included are details on areas on application, benefits/advantages, limitations/disadvantages, and costs associated with this technology. Information is provided on two demonstration sites at Fort Gillem, Georgia, and Fort Leavenworth, Kansas. Also provided is information concerning funding, procurement, maintenance, and performance monitoring. A fact sheet on recycling, contract specification example, and references are provided in the appendixes.... Asphalt pavement recycling, Emulsified asphalt cement, Cold milling, In-place cold-mix asphalt recycling, Cold-mix asphalt recycling, Recycling of asphalt.

Shoenberger, J.E.

1992-09-01

274

Enhanced adaptive filter-bank-based automated pavement crack detection and segmentation system  

NASA Astrophysics Data System (ADS)

We incorporate, evaluate, and assess the feasibility of using filter banks in automated pavement distress systems from a system level. We integrate a novel filter-bank-based distress segmentation method, which, unlike previously researched methods, does not depend on highpass data. In addition, we incorporate the standard Said Pearlman set partitioning in hierarchical trees compression coder into the automated pavement distress system, which is a first in this area of research. A third contribution of the research is a statistical detection algorithm that assists in overall system performance. Preliminary testing using images provided by the Georgia Department of Transportation demonstrate the promise of the proposed method.

Lettsome, Clyde A.; Tsai, Yi-Chang; Kaul, Vivek

2012-10-01

275

Beyond Address Spaces - Flexibility, Performance, Protection, and Resource Management in the Type-Safe JX Operating System  

Microsoft Academic Search

Early type-safe operating systems were hampered by poor performance. Contrary to these experiences we show that an operating system that is founded on an object-ori- ented, type-safe intermediate code can compete with MMU- based microkernels concerning performance while widen- ing the realm of possibilities. Moving from hardware-based protection to software- based protection offers new options for operating system quality, flexibility,

Michael Golm; Jürgen Kleinöder; Frank Bellosa

2001-01-01

276

Breaking/cracking and seating concrete pavements. Final report  

SciTech Connect

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

Thompson, M.R.

1989-03-01

277

Micro-thermal stress analysis of cement based pavement composite  

SciTech Connect

A four-layer sphere model for microscopic thermal analysis was proposed based upon the structural form of cement based pavement composites. Using temperature induced stresses of pavement structure as the external field, the micro-thermal stresses of two types of cement based pavement composite were calculated. The results showed that, by introducing the low stiffness rubberized asphalt in the interphase of coarse aggregate phase and cement mortar phase of Portland cement concrete, the interfacial thermal stresses could be reduced significantly, thus improving crack resistance of the pavement material under low temperature environment. Factors affecting micro-thermal stress of cement based pavement composite were discussed.

Li, G.; Zhao, Y.; Pang, S.S. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Mechanical Engineering; Huang, W. [Southeast Univ., Nanjing (China). Coll. of Transportation

1998-12-31

278

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

279

Speckle techniques for pavement surface analysis  

NASA Astrophysics Data System (ADS)

Speckle techniques are investigated for the characterization of pavement surface microtexture, particularly, height variations from one up to about ten micrometers in amplitude. Using the scalar diffraction theory of Kirchhoff, some simulations of the speckle contrast were carried out to bring out some patterns in case of a subjective speckle whose grains are not resolved by CCD photodetectors and in the case of a two-scale surface texture. We deduce the possibility of characterizing the fineness of the microtexture or its evolution versus wear modifying. The method is also experimentally applied to some reference surfaces (abrasive papers with various finenesses) and some models of pavement surfaces at various steps of wear.

Hun, Catherine; Caussignac, Jean-Marie; Bruynooghe, Michel M.

2003-05-01

280

Inkjet printing of flexible high-performance carbon nanotube transparent conductive films by ``coffee ring effect''  

NASA Astrophysics Data System (ADS)

Transparent and flexible conductors are a major component in many modern optoelectronic devices, such as touch screens for smart phones, displays, and solar cells. Carbon nanotubes (CNTs) offer a good alternative to commonly used conductive materials, such as metal oxides (e.g. ITO) for flexible electronics. The production of transparent conductive patterns, and arrays composed of connected CNT ``coffee rings'' on a flexible substrate poly(ethylene terephthalate), has been reported. Direct patterning is achieved by inkjet printing of an aqueous dispersion of CNTs, which self-assemble at the rim of evaporating droplets. After post-printing treatment with hot nitric acid, the obtained TCFs are characterized by a sheet resistance of 156 ? sq-1 and transparency of 81% (at 600 nm), which are the best reported values obtained by inkjet printing of conductive CNTs. This makes such films very promising as transparent conductors for various electronic devices, as demonstrated by using an electroluminescent device.

Shimoni, Allon; Azoubel, Suzanna; Magdassi, Shlomo

2014-09-01

281

Inkjet printing of flexible high-performance carbon nanotube transparent conductive films by "coffee ring effect".  

PubMed

Transparent and flexible conductors are a major component in many modern optoelectronic devices, such as touch screens for smart phones, displays, and solar cells. Carbon nanotubes (CNTs) offer a good alternative to commonly used conductive materials, such as metal oxides (e.g. ITO) for flexible electronics. The production of transparent conductive patterns, and arrays composed of connected CNT "coffee rings" on a flexible substrate poly(ethylene terephthalate), has been reported. Direct patterning is achieved by inkjet printing of an aqueous dispersion of CNTs, which self-assemble at the rim of evaporating droplets. After post-printing treatment with hot nitric acid, the obtained TCFs are characterized by a sheet resistance of 156 ? sq(-1) and transparency of 81% (at 600 nm), which are the best reported values obtained by inkjet printing of conductive CNTs. This makes such films very promising as transparent conductors for various electronic devices, as demonstrated by using an electroluminescent device. PMID:25014193

Shimoni, Allon; Azoubel, Suzanna; Magdassi, Shlomo

2014-10-01

282

Layer by layer evaluation of a PCC pavement as it was constructed: Comparison of backcalculated values to lab material values. Research investigation (final)  

SciTech Connect

This study was conducted to observe the background layer strengths of a pavement structure as each layer was constructed and compare these layer strengths to laboratory tested sample strengths. The objective was carried out by gathering Falling Weight Deflectometer deflection data on each sequential layer. The laboratory samples included bulk samples of the base, shelby tube samples of the subgrade, and concrete core samples from the pavement`s structure. Laboratory tests were performed on these extracted samples to estimate the resilient modulus testing on the base samples was not performed because the backcalculated base results were inconclusive and no comparison could be made.

Netemeyer, R.; Munsell, S.

1999-02-01

283

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

E-print Network

components; more drivers are affected, interactions in the traffic stream are more turbulent, and the potential for confusion and accidents is substantially greater. Exit-only signs and pavement markings are two methods used to communicate an exit lane drop...

Lance, Marty Tina

2012-06-07

284

Removable Urban Pavements: An innovative, sustainable technology Journal: International Journal of Pavement Engineering  

E-print Network

to the human environment, causing noise, air pollution and traffic congestion; moreover, they exert of the RUP concept in decreasing the public nuisance caused by pavement and road network maintenance work

Paris-Sud XI, Université de

285

Chip Seals for Asphalt Concrete Pavements: A Proposed Emulsion Residue Specification and Existing Pavement Texture Evaluation  

E-print Network

Analysis and Wavelet Transforms........................................................................... 42 AIMS Texture Analysis Using Height Measurements and Profiling ... 44 Ames Laser Texture Scanner... scanner to measure pavement macrotexture. ...................................................................................... 46 Figure 11 Texture measurement results from NCHRP Project 14-17 chip seal xiii...

Hoyt, Denise

2012-07-16

286

Project Information Form Project Title Evaluation of the Combined Effect of Recycled Asphalt Pavement (RAP),  

E-print Network

Pavement (RAP), Recycled Asphalt Shingles (RAS), and Different Virgin Binder Sources on Performance of the Blended Binder for Mixes with Higher Percentages of RAP and RAS University UC Davis Principal Investigator that is routinely recycled increases, it becomes more desirable to use significantly higher amounts of RAP and RAS

California at Davis, University of

287

Comparing finite element and constitutive modelling techniques for predicting rutting of asphalt pavements  

Microsoft Academic Search

This paper focuses on a comprehensive evaluation of the effects of different finite element (FE) modelling techniques and material constitutive models on predicting rutting in asphalt pavements under repeated loading conditions. Different simplified 2D and more realistic 3D loading techniques are simulated and compared for predicting asphalt rutting. This study also evaluates and compares the rutting performance predictions using different

Rashid K. Abu Al-Rub; Masoud K. Darabi; Chien-Wei Huang; Eyad A. Masad; Dallas N. Little

2012-01-01

288

Comparing finite element and constitutive modelling techniques for predicting rutting of asphalt pavements  

Microsoft Academic Search

This paper focuses on a comprehensive evaluation of the effects of different finite element (FE) modelling techniques and material constitutive models on predicting rutting in asphalt pavements under repeated loading conditions. Different simplified 2D and more realistic 3D loading techniques are simulated and compared for predicting asphalt rutting. This study also evaluates and compares the rutting performance predictions using different

Rashid K. Abu Al-Rub; Masoud K. Darabi; Chien-Wei Huang; Eyad A. Masad; Dallas N. Little

2011-01-01

289

Permeable Pavement Research at NRMRL?s Urban Watershed Research Facility  

EPA Science Inventory

The results of a bench-scale study of a porous pavement parking lot. Flow rates and total suspended solids (TSS) removal are discussed for systems with a geotextile filter fabric liner in place and those without. The systems with a liner have ~20% better TSS removal performance a...

290

Unintended Impacts of Increased Truck Loads on Pavement Supply-Chain Emissions  

E-print Network

Unintended Impacts of Increased Truck Loads on Pavement Supply-Chain Emissions Nakul Sathaye, Arpad by pavements. The supply chain associated with pavement maintenance and construction releases significant air tailpipe versus pavement supplychain emissions. In some cases, unintended emissions from the pavement

California at Berkeley, University of

291

Finite Element Investigation of the Deterioration of Doweled Rigid Pavements  

E-print Network

The purpose of this study is to describe the failure of concrete around dowel bars in jointed rigid pavements, and the resulting effect on the pavement performance. In fact, under repetitive vehicle loading, concrete in contact with the dowel bar deteriorates, particularly at the joint face. The degradation of concrete around the dowel negatively affects the latter's performance in terms of transferring wheel loads through vertical shear action. In this context, a nonlinear 3D Finite Element analysis was performed using the commercial FE code Abaqus (v-6.11). The FE model was validated with classical analytical solutions of shear and moment along the dowel. A concrete damaged plasticity model was used for the PCC slab to model the degradation of concrete matrix around the dowels under incremental loading. Results obtained show, among other things, that the degradation of concrete matrix around the dowel was found to initiate at the face of the joint and propagate towards the interior of the dowel. Also, results obtained confirmed the decrease in load transfer capability of the dowels as the PCC matrix deteriorates. The central dowels under the wheel load lost a significant portion of their load-transfer capacity as the PCC matrix around them deteriorated, while dowels farther away from the wheel load became more engaged in load transfer.

Ziad G. Ghauch

2011-11-03

292

ANALYSIS OF PERFORMANCE OF PULSATING FLEXIBLE MAGNETIC ABRASIVE BRUSH (P-FMAB)  

Microsoft Academic Search

Direct current magnetic abrasive finishing process provides hardly any stirring effect on static flexible magnetic abrasive brush (S-FMAB). Continuous use of S-FMAB and absence of stirring leads to dullness of abrasive cutting edges resulting in low finishing rate. To overcome this weakness of the process, the FMAB has been made pulsating using pulse direct current (DC) power supply. Empirical models

V. K. Jain; D. K. Singh; V. Raghuram

2008-01-01

293

Flexible SnO(2) hollow nanosphere film based high-performance ultraviolet photodetector.  

PubMed

A high-quality SnO(2) hollow-sphere nanofilm based flexible photodetector was constructed via'water-oil' interfacial assembling. The photodetector showed high sensitivity, superb stability, and was also able to bear significant external mechanical forces. PMID:23396397

Tian, Wei; Zhang, Chao; Zhai, Tianyou; Li, Song-Lin; Wang, Xi; Liao, Meiyong; Tsukagoshi, Kazuhito; Golberg, Dmitri; Bando, Yoshio

2013-05-01

294

Density and adhesion-controlled ZnO nanorod arrays on the ITO flexible substrates and their electrochromic performance  

Microsoft Academic Search

We report large-scale density- and adhesion-controlled ZnO nanorod arrays (NRs) directly grown on flexible ITO\\/PET substrates and have studied their absorption capability to viologen molecules and electrochromic performance. The density can be readily controlled by adjusting the thickness of pre-preparated ZnO seed layers. And the adhesion property of the ZnO NRs to substrates can be controlled by different methods of

Anzheng Hu; Fei Wu; Jinping Liu; Jian Jiang; Ruimin Ding; Xin Li; Cuixia Cheng; Zhihong Zhu; Xintang Huang

2010-01-01

295

Permeable pavement research ? Edison, New Jersey  

EPA Science Inventory

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

296

Desert pavement study at Amboy, California  

NASA Technical Reports Server (NTRS)

Desert pavement is a general term describing a surface that typically consists of a thin layer of cm-sized rock fragments set on top of a layer of finer material in which no fragments are found. An understanding of desert pavement is important to planetary geology because they may play a major role in the formation and visibility of various aeolian features such as wind streaks, which are important on Mars and may be important on Venus. A field study was conducted in Amboy, California to determine the formation mechanism of desert pavements. The probable sequence of events for the formation and evolution of a typical desert pavement surface, based on this experiment and the work of others, is as follows. Starting with a layer of surface material consisting of both fine particles and rock fragments, aeolian deflation will rapidly erode the surface until an armored lag is developed, after which aeolian processes become less important. The concentration of fragments then slowly increases as new fragments are brought to the surface from the subsurface and as fragments move downslope by sheet wash. Sheet wash would be responsible for removing very fine particles from the surface and for moving the fragments relative to one another, forming interlocks.

Williams, S.; Greeley, R.

1984-01-01

297

Impact of magnetic isolation on pointing system performance in the presence of structural flexibility  

NASA Technical Reports Server (NTRS)

The inertial pointing stability of a gimbal pointing system (AGS) was compared with a magnetic pointing/gimbal followup system (ASPS), under certain conditions of system structural flexibility and disturbance inputs from the gimbal support structure. Separate 3 degree-of-freedom (3DOF) linear models based on NASTRAN modal flexibility data for the gimbal and support structures were generated for the ASPS configurations. Using the models inertial pointing control loops providing 6dB of gain margin and 45 deg of phase margin were defined for each configuration. The pointing loop bandwidth obtained for the ASPS is more than twice the level achieved for the AGS configuration. The AGS limit is attributed to the gimbal and support structure flexibility. As a result of the higher ASPS pointing loop bandwidth and the disturbance rejection provided by the magnetic isolation ASPS pointing performane is significantly better than that of the AGS system. The low frequency peak of the ASPS transfer function from base disturbance to payload angular motion is almost 60dB lower than AGS low frequency peak.

Seller, J.

1985-01-01

298

Experimental Study on Geocell-Reinforced Recycled Asphalt Pavement (RAP) Bases under Static and Cyclic Loading  

E-print Network

Recycled Asphalt Pavement (RAP) is a removed and reprocessed pavement material containing asphalt and aggregates which can be used as a base course material for pavement applications. Geocells are a three-dimensional interconnected honeycomb type...

Thakur, Jitendra Kumar

2011-01-13

299

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Indian lands pavement management system (PMS). 973.208...Systems § 973.208 Indian lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2012-04-01

300

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Federal lands pavement management system (PMS). 970.208...Systems § 970.208 Federal lands pavement management system (PMS). In addition... (i) An inventory of the physical pavement features including the number of...

2012-04-01

301

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Federal lands pavement management system (PMS). 971.208...Systems § 971.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2013-04-01

302

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Federal lands pavement management system (PMS). 970.208...Systems § 970.208 Federal lands pavement management system (PMS). In addition... (i) An inventory of the physical pavement features including the number of...

2013-04-01

303

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

...2014-04-01 false Federal lands pavement management system (PMS). 971.208...Systems § 971.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2014-04-01

304

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

...2014-04-01 false Federal lands pavement management system (PMS). 970.208...Systems § 970.208 Federal lands pavement management system (PMS). In addition... (i) An inventory of the physical pavement features including the number of...

2014-04-01

305

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Federal lands pavement management system (PMS). 972.208...Systems § 972.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.”2 2...

2013-04-01

306

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Indian lands pavement management system (PMS). 973.208...Systems § 973.208 Indian lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2013-04-01

307

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Federal lands pavement management system (PMS). 972.208...Systems § 972.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.”2 2...

2012-04-01

308

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Federal lands pavement management system (PMS). 972.208...Systems § 972.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.”2 2...

2011-04-01

309

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

...2014-04-01 false Indian lands pavement management system (PMS). 973.208...Systems § 973.208 Indian lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2014-04-01

310

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Federal lands pavement management system (PMS). 970.208...Systems § 970.208 Federal lands pavement management system (PMS). In addition... (i) An inventory of the physical pavement features including the number of...

2011-04-01

311

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

Federal Register 2010, 2011, 2012, 2013

...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

312

Germanium nanoparticles encapsulated in flexible carbon nanofibers as self-supported electrodes for high performance lithium-ion batteries  

NASA Astrophysics Data System (ADS)

Germanium is a promising high-capacity anode material for lithium ion batteries, but still suffers from poor cyclability due to its huge volume variation during the Li-Ge alloy/dealloy process. Here we rationally designed a flexible and self-supported electrode consisting of Ge nanoparticles encapsulated in carbon nanofibers (Ge-CNFs) by using a facile electrospinning technique as potential anodes for Li-ion batteries. The Ge-CNFs exhibit excellent electrochemical performance with a reversible specific capacity of ~1420 mA h g-1 after 100 cycles at 0.15 C with only 0.1% decay per cycle (the theoretical specific capacity of Ge is 1624 mA h g-1). When cycled at a high current of 1 C, they still deliver a reversible specific capacity of 829 mA h g-1 after 250 cycles. The strategy and design are simple, effective, and versatile. This type of flexible electrodes is a promising solution for the development of flexible lithium-ion batteries with high power and energy densities.Germanium is a promising high-capacity anode material for lithium ion batteries, but still suffers from poor cyclability due to its huge volume variation during the Li-Ge alloy/dealloy process. Here we rationally designed a flexible and self-supported electrode consisting of Ge nanoparticles encapsulated in carbon nanofibers (Ge-CNFs) by using a facile electrospinning technique as potential anodes for Li-ion batteries. The Ge-CNFs exhibit excellent electrochemical performance with a reversible specific capacity of ~1420 mA h g-1 after 100 cycles at 0.15 C with only 0.1% decay per cycle (the theoretical specific capacity of Ge is 1624 mA h g-1). When cycled at a high current of 1 C, they still deliver a reversible specific capacity of 829 mA h g-1 after 250 cycles. The strategy and design are simple, effective, and versatile. This type of flexible electrodes is a promising solution for the development of flexible lithium-ion batteries with high power and energy densities. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00140k

Li, Weihan; Yang, Zhenzhong; Cheng, Jianxiu; Zhong, Xiongwu; Gu, Lin; Yu, Yan

2014-04-01

313

Asphalt Pavement Aging and TemperatureAsphalt Pavement Aging and Temperature Dependent Properties using a FunctionallyDependent Properties using a Functionally  

E-print Network

Asphalt Pavement Aging and TemperatureAsphalt Pavement Aging and Temperature Dependent Properties Analysis Time Integration Analysis Application Examples: Asphalt Pavement Summary and Conclusions #12) � Large fraction produced as hot-mix asphalt (HMA) � Most common form of pavement surfacing material (96

Paulino, Glaucio H.

314

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

315

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

316

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

SciTech Connect

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

Kurtis, K.E.; Monteiro, P.

1999-04-01

317

Solution processable colloidal nanoplates as building blocks for high-performance electronic thin films on flexible substrates.  

PubMed

Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for low-temperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane-plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6-15 nm) and lateral dimension (0.5-3 ?m) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm(2)·V(-1)·s(-1), approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics. PMID:25343683

Lin, Zhaoyang; Chen, Yu; Yin, Anxiang; He, Qiyuan; Huang, Xiaoqing; Xu, Yuxi; Liu, Yuan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

2014-11-12

318

Intra-Seasonal Flexibility in Avian Metabolic Performance Highlights the Uncoupling of Basal Metabolic Rate and Thermogenic Capacity  

PubMed Central

Stochastic winter weather events are predicted to increase in occurrence and amplitude at northern latitudes and organisms are expected to cope through phenotypic flexibility. Small avian species wintering in these environments show acclimatization where basal metabolic rate (BMR) and maximal thermogenic capacity (MSUM) are typically elevated. However, little is known on intra-seasonal variation in metabolic performance and on how population trends truly reflect individual flexibility. Here we report intra-seasonal variation in metabolic parameters measured at the population and individual levels in black-capped chickadees (Poecileatricapillus). Results confirmed that population patterns indeed reflect flexibility at the individual level. They showed the expected increase in BMR (6%) and MSUM (34%) in winter relative to summer but also, and most importantly, that these parameters changed differently through time. BMR began its seasonal increase in November, while MSUM had already achieved more than 20% of its inter-seasonal increase by October, and declined to its starting level by March, while MSUM remained high. Although both parameters co-vary on a yearly scale, this mismatch in the timing of variation in winter BMR and MSUM likely reflects different constraints acting on different physiological components and therefore suggests a lack of functional link between these parameters. PMID:23840843

Petit, Magali; Lewden, Agnes; Vezina, Francois

2013-01-01

319

Intra-seasonal flexibility in avian metabolic performance highlights the uncoupling of basal metabolic rate and thermogenic capacity.  

PubMed

Stochastic winter weather events are predicted to increase in occurrence and amplitude at northern latitudes and organisms are expected to cope through phenotypic flexibility. Small avian species wintering in these environments show acclimatization where basal metabolic rate (BMR) and maximal thermogenic capacity (MSUM) are typically elevated. However, little is known on intra-seasonal variation in metabolic performance and on how population trends truly reflect individual flexibility. Here we report intra-seasonal variation in metabolic parameters measured at the population and individual levels in black-capped chickadees (Poecileatricapillus). Results confirmed that population patterns indeed reflect flexibility at the individual level. They showed the expected increase in BMR (6%) and MSUM (34%) in winter relative to summer but also, and most importantly, that these parameters changed differently through time. BMR began its seasonal increase in November, while MSUM had already achieved more than 20% of its inter-seasonal increase by October, and declined to its starting level by March, while MSUM remained high. Although both parameters co-vary on a yearly scale, this mismatch in the timing of variation in winter BMR and MSUM likely reflects different constraints acting on different physiological components and therefore suggests a lack of functional link between these parameters. PMID:23840843

Petit, Magali; Lewden, Agnès; Vézina, François

2013-01-01

320

Carbon nanotube network film directly grown on carbon cloth for high-performance solid-state flexible supercapacitors  

NASA Astrophysics Data System (ADS)

Carbon nanotubes (CNTs) have received increasing attention as electrode materials for high-performance supercapacitors. We herein present a straightforward method to synthesize CNT films directly on carbon cloths as electrodes for all-solid-state flexible supercapacitors (AFSCs). The as-made highly conductive electrodes possess a three-dimensional (3D) network architecture for fast ion diffusion and good flexibility, leading to an AFSC with a specific capacitance of 106.1 F g-1, an areal capacitance of 38.75 mF cm-2, an ultralong cycle life of 100?000 times (capacitance retention: 99%), a good rate capability (can scan at 1000 mV s-1, at which the capacitance is still ˜37.8% of that at 5 mV s-1), a high energy density (2.4 ?W h cm-2) and a high power density (19 mW cm-2). Moreover, our AFSC maintains excellent electrochemical attributes even with serious shape deformation (bending, folding, etc), high mechanical pressure (63 kPa) and a wide temperature window (up to 100?° C). After charging for only 5 s, three such AFSC devices connected in series can efficiently power a red round LED for 60 s. Our work could pave the way for the design of practical AFSCs, which are expected to be used for various flexible portable/wearable electronic devices in the future.

Zhou, Cheng; Liu, Jinping

2014-01-01

321

High-performance all-solid-state flexible supercapacitors based on two-step activated carbon cloth  

NASA Astrophysics Data System (ADS)

A simple and effective strategy is proposed to activate carbon cloth for the fabrication of flexible and high-performance supercapacitors. Firstly, the carbon cloth surface is exfoliated as nanotextures through wet chemical treatment, then an annealing process is applied at H2/N2 atmosphere to reduce the surface oxygen functional groups which are mainly introduced from the first step. The activated carbon cloth electrode shows excellent wettablity, large surface area and delivers remarkable electrochemical performance. A maximum areal capacitance of 485.64 mF cm-2 at the current density of 2 mA cm-2 is achieved for the activated carbon cloth electrode, which is considerably larger than the resported results for carbon cloth. Furthermore, the flexible all-solid-state supercapacitor, which is fabricated based on the activated carbon cloth electrodes, shows high areal capacitance, superior cycling stability as well as stable electrochemical performance even under constant bending or twisting conditions. An areal capacitance of 161.28 mF cm-2 is achieved at the current density of 12.5 mA cm-2, and 104% of its initial capacitance is retained after 30,000 charging/discharging cycles. This study would also provide an effective way to boost devices' electrochemical performance by accommodating other active materials on the activated carbon cloth.

Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Long, Hu; Xi, Shuang; Hu, Hao; Tang, Zirong

2014-12-01

322

High-Performance NiO/Ag/NiO Transparent Electrodes for Flexible Organic Photovoltaic Cells.  

PubMed

Transparent electrodes with a dielectric-metal-dielectric (DMD) structure can be implemented in a simple manufacturing process and have good optical and electrical properties. In this study, nickel oxide (NiO) is introduced into the DMD structure as a more appropriate dielectric material that has a high conduction band for electron blocking and a low valence band for efficient hole transport. The indium-free NiO/Ag/NiO (NAN) transparent electrode exhibits an adjustable high transmittance of ?82% combined with a low sheet resistance of ?7.6 ?·s·q(-1) and a work function of 5.3 eV after UVO treatment. The NAN electrode shows excellent surface morphology and good thermal, humidity, and environmental stabilities. Only a small change in sheet resistance can be found after NAN electrode is preserved in air for 1 year. The power conversion efficiencies of organic photovoltaic cells with NAN electrodes deposited on glass and polyethylene terephthalate (PET) substrates are 6.07 and 5.55%, respectively, which are competitive with those of indium tin oxide (ITO)-based devices. Good photoelectric properties, the low-cost material, and the room-temperature deposition process imply that NAN electrode is a striking candidate for low-cost and flexible transparent electrode for efficient flexible optoelectronic devices. PMID:25148532

Xue, Zhichao; Liu, Xingyuan; Zhang, Nan; Chen, Hong; Zheng, Xuanming; Wang, Haiyu; Guo, Xiaoyang

2014-09-24

323

Stable bending performance of flexible organic light-emitting diodes using IZO anodes.  

PubMed

We report luminescent characteristics and mechanical stability of a flexible organic light-emitting diode (FOLED) using an amorphous ZnO-doped In2O3 (a-IZO) anode with a low sheet resistance of and a high optical transparency of 86%. The FOLED consisting of a-IZO/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4, 8-diyl)] (F8BT)/LiF/Al exhibits the efficient luminescent characteristics, which are nearly identical with the photoluminescence spectrum of the organic emitting material in our FOLED. This observation clearly indicates that the luminescent characteristics of the FOLED are solely ascribed to molecular exciton formation within the F8BT layer, since exciplex and charge transfer exciton formation are strictly suppressed by both tunneling/thermionic injection of holes at the PEDOT:PSS/F8BT interface and enhanced hole transport. Furthermore, the use of the considerably flexible a-IZO anode and PEDOT:PSS acting as a strain-relief buffering material enables good retention of the efficient luminescent characteristics of the FOLED even after continuous bending of up to 1000 times. PMID:24071803

Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

2013-01-01

324

Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping  

NASA Astrophysics Data System (ADS)

One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80 dB, a rise time 60 µs and the ability to measure ac signals up to ~250 kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies.

Saran, Rinku; Stolojan, Vlad; Curry, Richard J.

2014-05-01

325

Roswell International Air Center Airport (ROW) Pavement Condition and Analysis  

E-print Network

....................................................................................................................Runway 3-21 14 ..............................................................Figure 6. Base and Subgrade Analysis for Runway 3-21 14 Aircraft Used for Runway Pavement Design 25 ...................................................Table 7. FAA

Cal, Mark P.

326

Oxygen-deficient hematite nanorods as high-performance and novel negative electrodes for flexible asymmetric supercapacitors.  

PubMed

Oxygen-deficient ?-Fe2 O3 nanorods with outstanding capacitive performance are developed and demonstrated as novel negative electrodes for flexible asymmetric supercapacitors. The asymmetric-supercapacitor device based on the oxygen-deficient ?-Fe2 O3 nanorod negative electrode and a MnO2 positive electrode achieves a maximum energy density of 0.41 mW·h/cm(3) ; it is also capable of charging a mobile phone and powering a light-emitting diode indicator. PMID:24496961

Lu, Xihong; Zeng, Yinxiang; Yu, Minghao; Zhai, Teng; Liang, Chaolun; Xie, Shilei; Balogun, Muhammad-Sadeeq; Tong, Yexiang

2014-05-21

327

Correction: High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnOx nanocomposite electrodes.  

PubMed

Correction for 'High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnOx nanocomposite electrodes' by Geumbee Lee et al., Nanoscale, 2014, 6, 9655-9664. PMID:25365456

Lee, Geumbee; Kim, Daeil; Yun, Junyeong; Ko, Yongmin; Cho, Jinhan; Sook Ha, Jeong

2014-12-21

328

The influence of low-order chord-wise flexibility on the performance of a flapping wing  

NASA Astrophysics Data System (ADS)

The aerodynamic role of flexible fight structures in airborne creatures is still poorly understood. The objective of this study is to distill the basic phenomena of flapping with deformable wings for their use in the efficient design of bio-inspired flight vehicles. The target of the study is a two-dimensional wing with rigid components connected by damped torsion springs. This simplified structure reduces the complexity of the problem, while retaining the leading-order influence of wing flexion. The motion of the leading portion of the wing is prescribed with hovering-type kinematics, while the trailing portions respond passively. Numerical simulations are performed with a viscous vortex particle method with strongly-coupled structural dynamics. The investigation focuses on the influences of several key parameters: spring stiffness (from rigid to very flexible), the location of axis of rotation, and the timing between the rotational and translational components of the kinematics. The effects are quantified via several performance measures, including production of mean and rms lift, the mean consumption of power, and the lift per unit power. Some important correlations are identified between the input parameters and the performance metrics, the passive wing deflection and the wake structure. It is shown that variation in the rotation phase lead are accompanied by topological changes in the wake vortex dynamics.

Toomey, Jonathan; Eldredge, Jeff D.

2008-11-01

329

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

330

Laser Scribing of High-Performance and Flexible Graphene-Based Electrochemical Capacitors  

NASA Astrophysics Data System (ADS)

Although electrochemical capacitors (ECs), also known as supercapacitors or ultracapacitors, charge and discharge faster than batteries, they are still limited by low energy densities and slow rate capabilities. We used a standard LightScribe DVD optical drive to do the direct laser reduction of graphite oxide films to graphene. The produced films are mechanically robust, show high electrical conductivity (1738 siemens per meter) and specific surface area (1520 square meters per gram), and can thus be used directly as EC electrodes without the need for binders or current collectors, as is the case for conventional ECs. Devices made with these electrodes exhibit ultrahigh energy density values in different electrolytes while maintaining the high power density and excellent cycle stability of ECs. Moreover, these ECs maintain excellent electrochemical attributes under high mechanical stress and thus hold promise for high-power, flexible electronics.

El-Kady, Maher F.; Strong, Veronica; Dubin, Sergey; Kaner, Richard B.

2012-03-01

331

Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries  

NASA Astrophysics Data System (ADS)

Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 × 10-4 S cm-1) at 60°C and improved dimensional thermostability (up to 160°C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80°C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160°C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety.

Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

2014-09-01

332

Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries.  

PubMed

Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 × 10(-4) S cm(-1)) at 60°C and improved dimensional thermostability (up to 160°C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80°C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160°C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety. PMID:25183416

Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

2014-01-01

333

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

334

211. EQUIPMENT LAYING FIRST LANE OF CONCRETE PAVEMENT NEAR THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

211. EQUIPMENT LAYING FIRST LANE OF CONCRETE PAVEMENT NEAR THE CAPITAL OVERLOOK, 1931. NOTE THE BEGINNING OF BITUMINOUS TYPE OF TEMPORARY PAVEMENT TO ALLOW FOR SETTLEMENT IN HYDRAULIC FILL AREAS. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

335

Full-Depth Asphalt Pavements for Parking Lots and Driveways.  

ERIC Educational Resources Information Center

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

Asphalt Inst., College Park, MD.

336

Airport pavement management systems: an appraisal of existing methodologies  

Microsoft Academic Search

Airport pavement management systems (APMS) are computer-based decision support systems that can be used by the agencies running airports to determine cost-effective maintenance and rehabilitation strategies to preserve the various pavement structures (runways, taxiways, etc.) which are a critical component of these facilities. In this paper, we describe the main elements of APMS and review existing systems.

Michel Gendreau; Patrick Soriano

1998-01-01

337

Experimental study on properties of pervious concrete pavement materials  

Microsoft Academic Search

In this paper, a pervious concrete pavement material used for roadway is introduced. Using the common material and method, the strength of the pervious concrete is low. Using smaller sized aggregate, silica fume (SF), and superplasticizer (SP) in the pervious concrete can enhance the strength of pervious concrete greatly. The pervious pavement materials that composed of a surface layer and

Jing Yang; Guoliang Jiang

2003-01-01

338

Fracture resistance characterization of chemically modified crumb rubber asphalt pavement  

Microsoft Academic Search

The fracture resistance of chemically modified crumb rubber asphalt (CMCRA) pavement was evaluated based on the J-integral concept. The chemical modification process used was developed by the Federal Highway Administration and patented in 1998. The results were compared to that of crumb rubber asphalt (CRA) and control asphalt pavement. Four semi-circular core specimens (76 mm radius and 57 mm thickness)

M. A. Mull; K. Stuart; A. Yehia

2002-01-01

339

Portland Cement Concrete Pavement Shannon Golden, Alabama DOT  

E-print Network

be measured by weight. The substitution of each mineral admixture (GGBFS, Fly Ash, Silica Fume) for Portland* (Maximum % Substitution) Fly Ash (Maximum % Substutution) Silica Fume (Maximum % Substitution) 50 % 0 % 0Portland Cement Concrete Pavement Shannon Golden, Alabama DOT PORTLAND CEMENT CONCRETE PAVEMENT

340

Subgrade Temperature and Freezing Cycles in Pervious Pavements  

Microsoft Academic Search

With the construction of four new test cells in 2008, the Minnesota Department of Transportation (Mn\\/DOT) now has six unique pervious pavement test sections at the MnROAD test facility. Recorded temperatures in the pervious pavements and subgrades were compared to impervious Portland Cement Concrete (PCC) test sections over the same time interval. It was found that the subgrade in pervious

R. J. Rohne; M. A. Lebens

341

Regular Inspection and Maintenance Guidance for Porous Pavements  

E-print Network

. Signage should display limitation of design load (i.e. passenger vehicles only, light truck traffic, etc the pavement in accordance with the minimum design standards. This page provides guidance on maintenance non-design loads. Damaged areas may be repaired by use of infrared heating and rerolling of pavement

342

High-performance flexible ultraviolet photoconductors based on solution-processed ultrathin ZnO/Au nanoparticle composite films  

PubMed Central

Transparent ultraviolet (UV) ZnO thin film photoconductors are expected to have great applications in environmental monitoring, large-area displays, and optical communications, and they have drawn enormous interests in recent years. However, at present their performances are not satisfactory: the responsivity R (a parameter characterizing the sensitivity of the device to light) is not high (<1.0 × 103?AW?1), and the transparency T is not high either (<80%). Realizing high R and high T remains a big challenge today. In this paper, by employing solution-processed ultrathin ZnO/Au nanoparticle composite films, R as high as 1.51 × 105?AW?1 and T of over 90% are achieved. High values for detectivity D* and linear dynamic range LDR are also obtained, which are 2.05 × 1015 Jones and 60?dB, respectively. Moreover, such high-performance devices can be fabricated on flexible PET (polyethylene terephthalate) substrates. PMID:24589625

Jin, Zhiwen; Gao, Liang; Zhou, Qing; Wang, Jizheng

2014-01-01

343

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

344

Effect of pavement temperature on the macrotexture of a semidense asphalt surface  

E-print Network

Effect of pavement temperature on the macrotexture of a semidense asphalt surface J. Luong, M the pavement temperature could change the texture surface of the pavement. The aim of this work is to analyze the influence of the surface temperature on the macrotexture of a semidense asphalt pavement located in an urban

Boyer, Edmond

345

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 Project Depending on the type of surface pavement, permeable pavement can be termed as porous asphalt and improve water quality as well as urban heat island, the application of permeable pavement in urban areas

California at Davis, University of

346

Principles of bituminous pavement design and the recent trends Animesh Das1  

E-print Network

Principles of bituminous pavement design and the recent trends Animesh Das1 Introduction Understanding pavement behaviour is a complex task. This complexity is due to the complex response of the individual pavement materials which is very difficult to predict. In a typical pavement a number

Das, Animesh

347

Stiffness characterisation of full-scale airfield test pavements using computational intelligence techniques  

Microsoft Academic Search

The falling weight deflectometer (FWD) is a non-destructive test equipment used to assess the structural condition of highway and airfield pavement systems and to determine the moduli of pavement layers. The backcalculated moduli are not only good pavement layer condition indicators but are also necessary inputs for conducting mechanistic based pavement structural analysis. In this study, artificial neural networks (ANNs)-based

Kasthurirangan Gopalakrishnan; Halil Ceylan

2008-01-01

348

Flexible High-Performance Matrix Multiply via a Self-Modifying Runtime Code  

E-print Network

of such operations can be implemented in a relatively portable fashion provided a high-performance matrix-matrix multiplication itself can be implemented in a portable fashion provided a high-performance \\inner kernel with memory hierarchies help overcome the problem that often data movement is slow compared to computation

Batory, Don

349

Performance Test of a New Wet ESP with Flexible Collection Electrodes  

Microsoft Academic Search

Wet electrostatic precipitator (WESP) has been modernized over the last few decades. They were suitable for controlling slurry droplet, fine particles and acid aerosols. However, the applicability of current wet precipitators was badly limited for the imperfect mode of water film generation, back-corona, higher power consumption, corrosion of the collector surfaces. Tests were performed to investigate the performance of WESP

Chang Jingcai; Dong Yong; Yan Jun; Li Bing; Ma Chunyuan

2010-01-01

350

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

E-print Network

of cooling dense urban areas and reducing the urban heat11 island effect has been studied since the 1990's; pavement heat flux; pavement-watering; urban heat island; climate change25 adaptation; heat wave26 1 [3], this technique is viewed as an efficient means of reducing urban31 heat island (UHI) intensity

Paris-Sud XI, Université de

351

Ground rubber use in asphalt paving mixtures: A design and performance evaluation. Executive summary. Final report, 1 July 1991-30 June 1994  

SciTech Connect

The main objectives of the study were: (1) To determine if existing pavement mixture design procedures could be used in the design of rubberized pavements; (2) To determine the performance characteristics of rubberized mixtures in terms of crackng and rutting potential; (3) To compare the performance of rubberized and conventional pavement systems using a computer based performance prediction model; (4) To compare the life cycle costs of rubberized and conventional pavement systems.

Khosla, N.P.; Malpass, G.A.

1994-10-01

352

User's guide: Cold-mix recycling of asphalt concrete pavements. Final report  

Microsoft Academic Search

This guide provides the technical information required to implement the application of cold-mix recycling of asphalt concrete pavements. Included are details on areas on application, benefits\\/advantages, limitations\\/disadvantages, and costs associated with this technology. Information is provided on two demonstration sites at Fort Gillem, Georgia, and Fort Leavenworth, Kansas. Also provided is information concerning funding, procurement, maintenance, and performance monitoring. A

Shoenberger

1992-01-01

353

Tire Footprint Affects Hydroplaning On Wet Pavement  

NASA Technical Reports Server (NTRS)

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

Yager, Thomas J.

1989-01-01

354

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

Gavilan, Miguel; Balcones, David; Marcos, Oscar; Llorca, David F.; Sotelo, Miguel A.; Parra, Ignacio; Ocana, Manuel; Aliseda, Pedro; Yarza, Pedro; Amirola, Alejandro

2011-01-01

355

Solid-state high performance flexible supercapacitors based on polypyrrole-MnO2-carbon fiber hybrid structure.  

PubMed

A solid-state flexible supercapacitor (SC) based on organic-inorganic composite structure was fabricated through an "in situ growth for conductive wrapping" and an electrode material of polypyrrole (PPy)-MnO2 nanoflakes-carbon fiber (CF) hybrid structure was obtained. The conductive organic material of PPy greatly improved the electrochemical performance of the device. With a high specific capacitance of 69.3?F cm(-3) at a discharge current density of 0.1?A cm(-3) and an energy density of 6.16 × 10(-3)?Wh cm(-3) at a power density of 0.04?W cm(-3), the device can drive a commercial liquid crystal display (LCD) after being charged. The organic-inorganic composite active materials have enormous potential in energy management and the "in situ growth for conductive wrapping" method might be generalized to open up new strategies for designing next-generation energy storage devices. PMID:23884478

Tao, Jiayou; Liu, Nishuang; Ma, Wenzhen; Ding, Longwei; Li, Luying; Su, Jun; Gao, Yihua

2013-01-01

356

Solid-State High Performance Flexible Supercapacitors Based on Polypyrrole-MnO2-Carbon Fiber Hybrid Structure  

NASA Astrophysics Data System (ADS)

A solid-state flexible supercapacitor (SC) based on organic-inorganic composite structure was fabricated through an ``in situ growth for conductive wrapping'' and an electrode material of polypyrrole (PPy)-MnO2 nanoflakes-carbon fiber (CF) hybrid structure was obtained. The conductive organic material of PPy greatly improved the electrochemical performance of the device. With a high specific capacitance of 69.3 F cm-3 at a discharge current density of 0.1 A cm-3 and an energy density of 6.16 × 10-3 Wh cm-3 at a power density of 0.04 W cm-3, the device can drive a commercial liquid crystal display (LCD) after being charged. The organic-inorganic composite active materials have enormous potential in energy management and the ``in situ growth for conductive wrapping'' method might be generalized to open up new strategies for designing next-generation energy storage devices.

Tao, Jiayou; Liu, Nishuang; Ma, Wenzhen; Ding, Longwei; Li, Luying; Su, Jun; Gao, Yihua

2013-07-01

357

A flexible nonlinear model predictive control scheme for quality\\/performance handling in nonlinear SMB chromatography  

Microsoft Academic Search

In this paper, a new state feedback scheme is proposed for the control of simulated moving beds with strongly nonlinear isotherms. The proposed scheme offers a unified framework enabling different performance criteria to be improved according to the active production constraints (achieving low cost, improving efficiency, respecting deadlines) that may unpredictably change during the production batch. The proposed scheme is

Mazen Alamir; Fadi Ibrahim; Jean Pierre Corriou

2006-01-01

358

Flexibly Global? Performing Culture and Identity in an Age of Uncertainty  

ERIC Educational Resources Information Center

Presented as a symbolic interactive messy performance text, Michael Giardina sutures himself into and through the landscape of global social relations, including his own interpretive interactions of disconnection and reconnection with place, home, and nation. In so doing, and in these collages of lived textuality, he examines the complex,…

Giardina, Michael D.

2009-01-01

359

Platypus: Design and Implementation of a Flexible High Performance Object Store  

Microsoft Academic Search

This paper reports the design and implementation of Platypus, a trans- actional object store. The twin goals of fle xibility and performance dominate the design of Platypus. The design includes: support for SMP concurrency; stand- alone, client-server and client-peer distribution configurations; configurable log- ging and recovery; and object management which can accommodate garbage col- lection and clustering mechanisms. The first

Zhen He; Stephen M. Blackburn; Luke Kirby; John N. Zigman

2000-01-01

360

Pavement cracking measurements using 3D laser-scan images  

NASA Astrophysics Data System (ADS)

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

Ouyang, W.; Xu, B.

2013-10-01

361

Numerical analysis of active chordwise flexibility on the performance of non-symmetrical flapping airfoils  

NASA Astrophysics Data System (ADS)

This paper investigates the effect of active chordwise flexing on the lift, thrust and propulsive efficiency of three types of airfoils. The factors studied are the flexing center location, standard two-sided flexing as well as a type of single-sided flexing. The airfoils are simulated to flap with four configurations, and the effects of flexing under these configurations are investigated. Results show that flexing is not necessarily beneficial for the performance of the airfoils. However, with the correct parameters, efficiency is as high as 0.76 by placing the flexing centre at the trailing edge. The average thrust coefficient is more than twice as high, from 1.63 to 3.57 with flapping and flexing under the right conditions. Moreover, the single-sided flexing also gives an average lift coefficient as high as 4.61 for the S1020 airfoil. The shape of the airfoil does alter the effect of flexing too. Deviating the flexing phase angle away from 90° does not give a significant improvement to the airfoil’s performance. These results greatly enhance the design of a better performing ornithopter wing.

Tay, W. B.; Lim, K. B.

2010-01-01

362

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

363

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

364

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

365

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

366

Effect of wing inertia on hovering performance of flexible flapping wings  

NASA Astrophysics Data System (ADS)

Insect wings in flight typically deform under the combined aerodynamic force and wing inertia; whichever is dominant depends on the mass ratio defined as m?=?sh/(?fc), where ?sh is the surface density of the wing, ?f is the density of the air, and c is the characteristic length of the wing. To study the differences that the wing inertia makes in the aerodynamic performance of the deformable wing, a two-dimensional numerical study is applied to simulate the flow-structure interaction of a flapping wing during hovering flight. The wing section is modeled as an elastic plate, which may experience nonlinear deformations while flapping. The effect of the wing inertia on lift production, drag resistance, and power consumption is studied for a range of wing rigidity. It is found that both inertia-induced deformation and flow-induced deformation can enhance lift of the wing. However, the flow-induced deformation, which corresponds to the low-mass wing, produces less drag and leads to higher aerodynamic power efficiency. In addition, the wing deformation has a significant effect on the unsteady vortices around the wing. The implication of the findings on insect flight is discussed.

Yin, Bo; Luo, Haoxiang

2010-11-01

367

Robotic vehicle mobility and task performance: A flexible control modality for manned systems  

NASA Technical Reports Server (NTRS)

In the early 1980's, a number of concepts were developed for applying robotics to ground systems. The majority of these early application concepts envisioned robotics technology embedded in dedicated unmanned systems; i.e., unmanned systems with no provision for direct manned control of the platform. Although these concepts offered advantages peculiar to platforms designed from the outset exclusively for unmanned operation--i.e., no crew compartment--their findings would require costs and support for a new class of unmanned systems. The current era of reduced budgets and increasing focus on rapid force projection has created new opportunities to examine the value of an alternative concept: the use of existing manned platforms with an ability to quickly shift from normal manned operation to unmanned should a particularly harzardous situation arise. The author of this paper addresses the evolution of robotic vehicle concepts and technology testbeds from exclusively unmanned systems to a variety of 'optionally manned' systems which have been designed with minimum intrusion actuator and control equipment to minimize degradation of vehicle performance in manned modes of operation.

Eldredge, Frederick

1994-01-01

368

Ecological restoration and soil improvement performance of the seabuckthorn flexible dam in the Pisha Sandstone area of Northwestern China  

NASA Astrophysics Data System (ADS)

Soil erosion of the Pisha Sandstone area of Loess Plateau is extremely severe in China. The Pisha Sandstone is very hard when it is dry, while it is very frail when wet. The seabuckthorn flexible dam (SFD), a type of ecological engineering, was proposed to control soil erosion and meliorate soil within the Pisha Sandstone area. To assess its effectiveness and the ecological restoration and soil improvement performance, a field experiment was conducted in this area. We found the strong sediment retention capacity of the SFD is the basis of using it to restore the ecosystem. We compared some certain ecological factors and soil quality between a gully with the SFD and a gully without the SFD, including soil moisture, soil organic matter (SOM), soil nutrients (including Ammonia Nitrogen, available phosphorus and Potassium), vegetation coverage and biodiversity. The results showed that the SFD exhibits excellent performance for ecological restoration and soil improvement of this area. The results are as follows: (i) by the sediment retention action, the deposition commonly occurred in the SFD gully, and the deposition patterns are obviously different from upper to lower gully, (ii) more surprisingly, unlike trees or other shrubs, the seabuckthorn has good horizontal extending capacity by its root system, (iii) soil moisture, SOM, soil nutrients, vegetation coverage and biodiversity in the vegetated gully with the SFD are all markedly increased. The results showed the SFD is both effective and novel biological measure for ecological restoration and soil improvement within the Pisha Sandstone area.

Yang, F. S.; Cao, M. M.; Li, H. E.; Wang, X. H.; Bi, C. F.

2014-09-01

369

Flexible CoAl LDH@PEDOT core/shell nanoplatelet array for high-performance energy storage.  

PubMed

A CoAl-layered double hydroxide (LDH)@poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanoplatelet array (NPA) is grown on a flexible Ni foil substrate as a high-performance pseudocapacitor. The LDH@PEDOT core/shell NPA shows a maximum specific capacitance of 649 F/g (based on the total mass) by cyclic voltammetry (scan rate: 2 mV/s) and 672 F/g by galvanostatic discharge (current density: 1 A/g). Furthermore, the hybrid NPA electrode also exhibits excellent rate capability with a specific energy of 39.4 Wh/kg at a current density of 40 A/g, as well as good long-term cycling stability (92.5% of its original capacitance is retained after 5000 cycles). These performances are superior to those of conventional supercapacitors and LDH NPA without the PEDOT coating. The largely enhanced pseudocapacitor behavior of the LDH@PEDOT NPA electrode is related to the synergistic effect of its individual components: the LDH nanoplatelet core provides abundant energy-storage capacity, while the highly conductive PEDOT shell and porous architecture facilitate the electron/mass transport in the redox reaction. PMID:22961997

Han, Jingbin; Dou, Yibo; Zhao, Jingwen; Wei, Min; Evans, David G; Duan, Xue

2013-01-14

370

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded Viscoelastic Model, Part-I: Development,  

E-print Network

Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded simulations, correspondence principle, finite-element method Abstract. Asphalt concrete pavements to climatic conditions are the major cause of such graded non-homogeneity. Current pavement analysis

Paulino, Glaucio H.

371

3-D Seismic Methods for Shallow Imaging Beneath Pavement  

E-print Network

The research presented in this dissertation focuses on survey design and acquisition of near-surface 3D seismic reflection and surface wave data on pavement. Increased efficiency for mapping simple subsurface interfaces ...

Miller, Brian

2013-05-31

372

Implications of reliability in mechanistic/empirical pavement design applications  

E-print Network

At present there are many design procedures for both asphalt and concrete pavement structures. The object of any one of these design procedures being to produce a quality riding structure that will satisfy the design engineer and the riding public...

Killingsworth, Brian Mark

2012-06-07

373

Long-Life Concrete Pavements in Europe and Canada.  

National Technical Information Service (NTIS)

Long-life concrete pavements require less frequent repair and rehabilitation and contribute to highway safety and congestion mitigation. The Federal Highway Administration, American Association of State Highway and Transportation Officials, and National C...

A. Correa, D. Dawood, K. Hall, R. Tally, S. Vanikar, T. Cackler

2007-01-01

374

Las Cruces International Airport (LRU) Pavement Condition and Analysis  

E-print Network

. Design Aircraft Used for Runway Pavement Design 20 1. Las Cruces International Airport (LRU) Aircraft Operations (2008-09) 5 .........Table 2. Las Cruces International Airport (LRU) Predicted Aircraft Operations 2007-2027 6 .............Figure 2. Las

Cal, Mark P.

375

Clayton Municipal Airport (CAO) Pavement Condition and Analysis  

E-print Network

;........................................................................................4. Recommend Pavement Design 19 .........................................Table 5. Design Aircraft Used Airport (CAO) Aircraft Operations (2005-2009) 5 .....Table 2. Clayton Municipal Airport (CAO) Predicted Aircraft Operations 2007-2027 6 ..................Figure 2. Clayton Municipal Airport (CAO) PCI Branch Map

Cal, Mark P.

376

Double Eagle II Airport (AEG) Pavement Condition and Analysis  

E-print Network

........................................................................................4. Recommend Pavement Design 17 .........................................Table 5. Design Aircraft. Double Eagle II (AEG) Aircraft Operations (2006) 5 .......................Table 2. Double Eagle II (AEG) Predicted Aircraft Operations 2010-2025 6 ..................................................Figure 2. Double

Cal, Mark P.

377

Moriarty Municipal Airport (0E0) Pavement Condition and Analysis  

E-print Network

. Design Aircraft Used for Runway Pavement Design 20 ..................................................Table 1. Moriarty Airport (0E0) Aircraft Operations (2007-2008) 5 ....................................Table 2. Moriarty Airport (0E0) Predicted Aircraft Operations 2007-2027 6

Cal, Mark P.

378

Sierra Blanca Ruidoso Airport (SRR) Pavement Condition and Analysis  

E-print Network

. Design Aircraft Used for Runway Pavement Design 19 .................................................Table 1. Sierra Blanca Ruidoso (SRR) Aircraft Operations (2007) 5 ..........................Table 2. Sierra Blanca Ruidoso (SRR) Predicted Aircraft Operations 2007-2027 6

Cal, Mark P.

379

Raton Municipal Airport (RTN) Pavement Condition and Analysis  

E-print Network

Aircraft Used for Runway Pavement Design 20 .............................................Table 1. Raton Municipal Airport (RTN) Aircraft Operations (2008) 5 ......................Table 2. Raton Municipal Airport (RTN) Predicted Aircraft Operations 2007-2027 6 ..................................Figure 2

Cal, Mark P.

380

Belen Alexander Municipal Airport (E80) Pavement Condition and Analysis  

E-print Network

;................................................................................................4. Recommend Pavement Design 19 .................................................Table 5. Design Aircraft Used Municipal Airport (E80) Aircraft Operations (2007-2008) 5 .....Table 2. Belen Alexander Municipal Airport (E80) Predicted Aircraft Operations 2010-25 6 ...............Figure 2. Belen Alexander Municipal

Cal, Mark P.

381

Silver City Grant County Airport (SVC) Pavement Condition and Analysis  

E-print Network

. Recommend Pavement Design 19 ......................................................Table 5. Design Aircraft. Silver City Grant County Airport (SVC) Aircraft Operations (2008-2009) 5 .........Table 2. Silver City Grant County Airport (SVC) Predicted Aircraft Operations 2007-2027 6 ............................Figure

Cal, Mark P.

382

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

383

Permeable Pavement Demonstration at the Edison Environmental Center - Poster  

EPA Science Inventory

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

384

User's Guide: Cold-Mix Recycling of Asphalt Concrete Pavements.  

National Technical Information Service (NTIS)

This guide provides the technical information required to implement the application of cold-mix recycling of asphalt concrete pavements. Included are details on areas on application, benefits/advantages, limitations/disadvantages, and costs associated wit...

J. E. Shoenberger

1992-01-01

385

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

386

Assessing the improved performance of freestanding, flexible graphene and carbon nanotube hybrid foams for lithium ion battery anodes  

NASA Astrophysics Data System (ADS)

We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode.We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode. Electronic supplementary information (ESI) available: ESI is available that includes (i) SEM and photographs of ultra-thin graphite foams, (ii) Raman spectra from SWNT and ultrathin graphite foams, (iii) CV measurements at higher scan rates, (iv) comparison of discharge characteristics of first, second, and 300th discharge, (v) Ragone plot showing power-energy characteristics of hybrid graphene-SWNT electrodes, and (vi) TEM images of multilayered graphene edges from graphene and graphene-SWNT hybrids, with interlayer spacing maps and FFT analysis. See DOI: 10.1039/c4nr00390j

Cohn, Adam P.; Oakes, Landon; Carter, Rachel; Chatterjee, Shahana; Westover, Andrew S.; Share, Keith; Pint, Cary L.

2014-04-01

387

Evaluation of transverse piezoelectric coefficient of ZnO thin films deposited on different flexible substrates: a comparative study on the vibration sensing performance.  

PubMed

We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology. PMID:24773266

Joshi, Sudeep; Nayak, Manjunatha M; Rajanna, K

2014-05-28

388

Rehabilitation of continuously reinforced concrete pavements using overlays  

E-print Network

REHABILITATION OF CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS USING OVERLAYS A Thesis by SOUMYA SRIRAMAN Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 1993 Major Subject: Civil Engineering REHABILITATION OF CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS USING OVERLAYS A Thesis by SOUMYA SRIRAMAN Submitted to Texas A&M University in partial fulfillment of the requirements for the degree...

Sriraman, Soumya

2012-06-07

389

Mechanistic modeling of roughness on continuously reinforced concrete pavement  

E-print Network

MECHANISTIC MODELING OF ROUGHNESS ON CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS A Thesis by SUPRIYA SRIRAMAN Submitted to the OAice of graduate Studies of Texas ASM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1996 Major Subject: Civil Engineering MECHANISTIC MODELING OF ROUGHNESS ON CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS A Thesis by SUPRIYA SRI~ Submitted to Texas A&M University in partial fulfillment of the requirements...

Sriraman, Supriya

2012-06-07

390

Pavement rehabilitation and funds allocation for a transportation network  

E-print Network

PAVEMENT REHABILITATION AND FUNDS ALLOCATION FOR A TRANSPORTATION NETWORK A Thesis by ALVARO STEIN Submitted to the Graduate College of Texas ASM University in Partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December 1985 Major Subject: Industrial Engineering PAVEMENT REHABILITATION AND FUNDS ALLOCATION FOR A TRANSPORTATION NETWORK A Thesis by ALVARO STEIN Approved as to style and content by: Donald R. Smith (Co-Chai rman of Committee) Robe L. tton...

Stein, Alvaro

2012-06-07

391

Automatic Asphalt pavement crack detection and classification using Neural Networks  

Microsoft Academic Search

Managing of road maintenance is the most complex task for road administrations. The first presumption for the evaluation analysis and correct road construction rehabilitation is to have accurate and up-to-date information about road pavement condition. As the pavement condition survey is a critical process, it needs fast and cost-effective methods to collect necessary data. The paper proposes a system for

T. Saar; O. Talvik

2010-01-01

392

Neural networks based concrete airfield pavement layer moduli backcalculation  

Microsoft Academic Search

The Heavy Weight Deflectometer (HWD) is a Non-Destructive Test (NDT) equipment used to assess the structural condition of airfield pavement systems. This paper presents an Artificial Neural Networks (ANN) based approach for non-destructively estimating the stiffness properties of rigid airfield pavements subjected to full-scale dynamic traffic testing using simulated new generation aircraft gears. HWD tests were routinely conducted on three

Halil Ceylan; Kasthurirangan Gopalakrishnan; M. Birkan Bayrak

2008-01-01

393

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

SciTech Connect

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

Not Available

1994-05-01

394

Softening agents for recycling asphalt pavement  

SciTech Connect

An asphaltic composition is described consisting essentially of: comminuted aged asphaltic pavement material; an effective amount, from about 2% to about 15 % by weight of a blend of an agent selected from the group consisting of a soft asphalt cement, a conventional asphalt cement, and a cutback asphalt, with a nitrogen-containing, adhesion-improving, anti-stripping agent comprising a sewage sludge-derived oil, or a fraction thereof, said sewage sludge-derived oil comprising a mixture of saturated aliphatic hydrocarbons, monoaromatic hydrocarbons, diaromatic hydrocarbons, polyaromatic hydrocarbons, polar compounds and basic, pyridene-soluble compounds, having the following elemental chemical composition: nitrogen, about 3.4% to about 5% by weight; oxygen, about 5.8% to about 6.9% by weight; sulfur, about 0.3% to about 0.8% by weight; hydrogen, about 9.7% to about 10.4%, and carbon, about 76.9% to about 79.8%.

Sawatzky, H.; Clelland, F.I.; Farnand, B.A.; Houde, J. Jr.

1993-08-10

395

Flexible Acculturation  

E-print Network

-state and family — are relatively insufficient. In this paper, I explore the concept of “flexible acculturation,” first proposed by Jan Nederveen-Pieterse (2007), to show a cultural aspect of transnational flexibility. I situate my discussion in the literature...

Lee, Hsiang-Chieh

2008-01-01

396

Flexible asymmetric supercapacitors based on ultrathin two-dimensional nanosheets with outstanding electrochemical performance and aesthetic property.  

PubMed

Flexible asymmetric supercapacitors with excellent electrochemical performance and aesthetic property are realized by using ultrathin two-dimensional (2D) MnO2 and graphene nanosheets as cathode and anode materials, respectively. 2D MnO2 nanosheets (MSs) with a thickness of ca. 2 nm are synthesized with a soft template method for the first time, which achieve a high specific capacitance of 774 F g(-1) even after 10000 cycles. Asymmetric supercapacitors based on ultrathin MSs and graphene exhibit a very high energy density up to 97.2 Wh kg(-1) with no more than 3% capacitance loss after 10000 cycles in aqueous electrolyte. Most interestingly, we show that the energy storage device can have an aesthetic property. For instance, a "Chinese panda" supercapacitor is capable of lighting up a red light emitting diode. This work has another, quite different aspect that a supercapacitor is no longer a cold industry product, but could have the meaning of art. PMID:24008931

Shi, Shan; Xu, Chengjun; Yang, Cheng; Chen, Yanyi; Liu, Juanjuan; Kang, Feiyu

2013-01-01

397

Performance oriented packaging testing of the six-foot flexible linear shaped charge box for packing group II hazardous materials. Final report  

SciTech Connect

The wood box (Drawing 53711-6665109) for six-foot flexible linear shaped charges was tested for conformance to Performance Oriented Packaging standards specified by the Code of Federal Regulations, Title 49 CFR, Parts 107 through 178, dated 31 December 1991. The box was tested with a gross weight of 14 kilograms and met all the requirements.

Libbert, K.J.

1992-10-01

398

High-performance large-scale flexible dye-sensitized solar cells based on anodic TiO2 nanotube arrays.  

PubMed

A simple strategy to fabricate flexible dye-sensitized solar cells involves the use of photoanodes based on TiO2 nanotube (TNT) arrays with rear illumination. The TNT films (tube length ?35 ?m) were produced via anodization, and sensitized with N719 dye for photovoltaic characterization. Pt counter electrodes of two types were used: a conventional FTO/glass substrate for a device of rigid type and an ITO/PEN substrate for a device of flexible type. These DSSC devices were fabricated into either a single-cell structure (active area 3.6×0.5 cm2) or a parallel module containing three single cells (total active area 5.4 cm2). The flexible devices exhibit remarkable performance with efficiencies ?=5.40% (single cell) and 4.77% (parallel module) of power conversion, which outperformed their rigid counterparts with ?=4.87% (single cell) and 4.50% (parallel model) under standard one-sun irradiation. The flexible device had a greater efficiency of conversion of incident photons to current and a broader spectral range than the rigid device; a thinner electrolyte layer for the flexible device than for the rigid device is a key factor to improve the light-harvesting ability for the TNT-DSSC device with rear illumination. Measurements of electrochemical impedance spectra show excellent catalytic activity and superior diffusion characteristics for the flexible device. This technique thus provides a new option to construct flexible photovoltaic devices with large-scale, light-weight, and cost-effective advantages for imminent applications in consumer electronics. PMID:24050628

Jen, Hsiu-Ping; Lin, Meng-Hung; Li, Lu-Lin; Wu, Hui-Ping; Huang, Wei-Kai; Cheng, Po-Jen; Diau, Eric Wei-Guang

2013-10-23

399

Microporous Ni11(HPO3)8(OH)6 nanocrystals for high-performance flexible asymmetric all solid-state supercapacitors.  

PubMed

Microporous nickel phosphite [Ni11(HPO3)8(OH)6] nanocrystals were prepared using a hydrothermal method, and were successfully applied as a positive electrode in a flexible all solid-state asymmetric supercapacitor. Because of the specific micro/nanostructure, the flexible solid-state asymmetric supercapacitor can achieve a maximum energy density of 0.45 mW h cm(-3), which is higher than most reported supercapacitors. More importantly, the device performance remains efficient for 10?000 cycles. PMID:25329036

Gao, Yanping; Zhao, Junhong; Run, Zhen; Zhang, Guangqin; Pang, Huan

2014-10-28

400

Low temperature preparation of a high performance Pt\\/SWCNT counter electrode for flexible dye-sensitized solar cells  

Microsoft Academic Search

A platinum\\/single-wall carbon nanotube (Pt\\/SWCNT) film was sprayed onto a flexible indium-doped tin oxide coated polyethylene naphthalate (ITO\\/PEN) substrate to form a counter electrode for use in a flexible dye-sensitized solar cell using a vacuum thermal decomposition method at low temperature (120°C). The obtained Pt\\/SWCNT electrode showed good chemical stability and light transmittance and had lower charge transfer resistance and

Yaoming Xiao; Jihuai Wu; Gentian Yue; Jianmin Lin; Miaoliang Huang; Zhang Lan

2011-01-01

401

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

402

Over the Edge and Back: What to Do If You Drive Off the Pavement Edge  

MedlinePLUS

AAA Foundation for Traffic Safety Over the Edge and Back What to do if you drive off ... fatal relative to other crashes on similar roads. AAA Foundationfor Traffic Safety Pavement edge drop-off “ Pavement ...

403

An investigation of factors that significantly affect pavement maintenance costs in Texas  

E-print Network

including average daily traffic, equivalent single axle loads, distress score, ride score, annual rainfall, annual freeze/thaw cycles, functional classification, as well as the district that maintains the pavement. For each pavement type and highway...

Fogle, Kendall Lee

2012-06-07

404

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 ...

405

High-performance plastic platinized counter electrode via photoplatinization technique for flexible dye-sensitized solar cells.  

PubMed

A photoplatinization technique was proposed to deposit Pt on a thin TiO(2) layer modified indium tin oxide-coated polyethylene naphthalate (ITO/PEN) substrate at low temperature (about 50 °C after 1 h of UV irradiation) for the first time. The fabrication process includes coating and hydrolyzing the tetra-n-butyl titanate to form a TiO(2)-modified layer and the photoplatinization of the modified substrate in H(2)PtCl(6)/2-propanol precursor solution under UV irradiation. The obtained platinized electrodes were used as counter electrodes (CE) for flexible dye-sensitized solar cells (FDSCs). The well-optimized platinized electrode showed high optical transmittance, up to 76.5% between 400 and 800 nm (T(av)), and the charge transfer resistance (R(ct)) was as low as 0.66 ? cm(2). A series of characterizations also demonstrated the outstanding chemical/electrochemical durability and mechanical stability of the platinized electrode. The FDSCs with TiO(2)/Ti photoanodes and the obtained CEs achieved a power conversion efficiency (PCE) up to 8.12% under rear-side irradiation (AM 1.5 illumination, 100 mW cm(-2)). The obtained CEs were also employed in all-plastic bifacial DSCs. When irradiated from the rear side, the bifacial FDSC yielded a PCE of 6.26%, which approached 90% that of front-side irradiation (6.97%). Our study revealed that, apart from serving as a functional layer for deposition of Pt, the thin TiO(2) layer modification on ITO/PEN substrates also played an important role in improving the transparency and the mechanical properties of the CE. The effect of the thickness of the TiO(2) layer for Pt coating on the performance of the CE was also investigated. PMID:23039879

Fu, Nian-Qing; Fang, Yan-Yan; Duan, Yan-Dong; Zhou, Xiao-Wen; Xiao, Xu-Rui; Lin, Yuan

2012-11-27

406

Determining the sidewalk pavement width by using pedestrian discomfort levels and movement characteristics  

Microsoft Academic Search

This paper presents a sidewalk pavement width design method for making more pedestrian friendly and walk-inspiring sidewalk\\u000a pavements in the urban area. Instead of using the current sidewalk pavement width design standard that usually leads to having\\u000a minimum values, this research investigated pedestrians’ preferences on the levels of service, surveyed actual foot path trajectories\\u000a in the sidewalk pavements, and observed

Sangyoup Kim; Jaisung Choi; Yongseok Kim

2011-01-01

407

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

408

Development of ground-penetrating radar equipment for detecting pavement condition for preventive maintenance  

NASA Astrophysics Data System (ADS)

The report documents the development of a ground penetrating radar (GPR) system for locating potential maintenance problems in highway pavements. The report illustrates how GPR has the potential to detect four defects in pavements: stripping in an asphalt layer; moisture in base layer; voids or loss of support under rigid pavements; and overlay delamination.

Smith, S. S.; Scuillion, T.

1993-10-01

409

AUTOMATIC DETECTION AND CLASSIFICATION OF DEFECT ON ROAD PAVEMENT USING ANISOTROPY MEASURE  

E-print Network

AUTOMATIC DETECTION AND CLASSIFICATION OF DEFECT ON ROAD PAVEMENT USING ANISOTROPY MEASURE Tien Sy-sy.nguyen@etu.univ-orleans.fr ABSTRACT Existing systems for automated pavement defect detection can only identify cracking type defects for the inspectors and road users [1]. In the last few years, several automated pavement inspecting systems which use

Paris-Sud XI, Université de

410

Pavement Boundary Detection Via Circular Shape Models Bing Ma \\Lambda Sridhar Lakshmanan Alfred O. Hero  

E-print Network

Pavement Boundary Detection Via Circular Shape Models Bing Ma \\Lambda Sridhar Lakshmanan Alfred O bingm@umich.edu lakshman@umich.edu hero@eecs.umich.edu Abstract Automated detection of pavement of art systems for detecting and tracking pavement boundaries use a priori shape models to describe

Hero, Alfred O.

411

LRRB Pavement Management SystemsTraffic Generator Managing Interaction Between Local  

E-print Network

LRRB Pavement Management SystemsTraffic Generator Managing Interaction Between Local Authorities Research Board May 24, 2011 22nd Annual Transportation Research Conference #12;LRRB Pavement ManagementSCU, Consultants, etc. · Administered by Mn/DOT Research Services LRRB Funding #12;LRRB Pavement Management Systems

Minnesota, University of

412

Advanced Characterisation of Pavement and Soil Engineering Materials Loizos, Scarpas & Al-Qadi (eds)  

E-print Network

1241 Advanced Characterisation of Pavement and Soil Engineering Materials � Loizos, Scarpas & Al and economical alternative for the repair of deteriorated pavements, reflective cracking continues to be major approaches have not provided a direct means for the study of crack initiation and propagation in pavements

Paulino, Glaucio H.

413

A four-point bending test for the bonding evaluation of composite pavement  

E-print Network

A four-point bending test for the bonding evaluation of composite pavement M. Hun1 , A. Chabot1 , F investigate the crack initiation and propagation at the interface between layers of composite pavements affects the durability of composite pavements made with asphalt and cement materials. Two main problems

Paris-Sud XI, Université de

414

PAPER PREPARATION GUIDELINES FOR THE 2014 INTERNATIONAL SYPOSIUM ON PAVEMENT LIFE-CYCLE ASSESSMENT  

E-print Network

PAPER PREPARATION GUIDELINES FOR THE 2014 INTERNATIONAL SYPOSIUM ON PAVEMENT LIFE-CYCLE ASSESSMENT (PAVEMENT LCA - 2014) PAPER SUBMISSION Completed papers must be submitted electronically in a single PDF, as follows, to meet the requirements for Pavement LCA - 2014. All papers must be submitted in English

California at Davis, University of

415

A Robust Bayesian Fusion Algorithm for Lane and Pavement boundary detection  

E-print Network

1 A Robust Bayesian Fusion Algorithm for Lane and Pavement boundary detection Bing Ma, Sridhar Lakshmanan, Alfred O. Hero Abstract In this paper we propose to jointly detect lane and pavement boundaries is employed to locate the lane and pavement boundaries. Since the circular model parameters possess compatible

Hero, Alfred O.

416

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 the contour between pavements and roads. The method uses a quasi-flat zone algorithm and a region adjacency boundary. Finally, edges with a value compatible with the pavement/road difference (about 14[cm

Cord, Aurélien

417

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 pavements consider flat interfaces for simpli- fication. In this paper, the roughness of the surfaces is taken into account. First, the amplitudes of the first two echoes from the rough thin pavement

Paris-Sud XI, Université de

418

Environmental Assessment of Pavement Alternatives: Decision-Making in Light of  

E-print Network

Environmental Assessment of Pavement Alternatives: Decision-Making in Light of Current Knowledge, Davis, USA and University of California Pavement Research Center Davis, Berkeley UCLA Lake Arrowhead Symposium October 17-19, 2010 #12;What is the pavement infrastructure? � Freeways, highways � Roads

Handy, Susan L.

419

Concrete Pavement I-285 under 5th runway at Hartsfield Jackson  

E-print Network

Concrete Pavement Sweet as a James Page I-285 under 5th runway at Hartsfield Jackson International Concrete Paving project I-285 East Perimeter Fiscal 2012 GDOT placed 205,704 square yards of RCC Pavement Portland Cement Concrete Pavement State Route 96 Crawford / Peach Counties I-75 Tift County CRC Lane

420

CrackTree: Automatic crack detection from pavement images Qin Zou a,b,c,  

E-print Network

CrackTree: Automatic crack detection from pavement images Qin Zou a,b,c, , Yu Cao c , Qingquan Li b t Pavement cracks are important information for evaluating the road condition and conducting the neces- sary pavement images. In practice, crack detection is a very challenging problem because of (1) low con- trast

Wang, Song

421

5-9035-01-P4 4-YEAR PAVEMENT MANAGEMENT PLAN (WITH  

E-print Network

5-9035-01-P4 4-YEAR PAVEMENT MANAGEMENT PLAN (WITH PROPOSITION 12 PROJECTS): ANALYSIS REPORT Implementation of a Web-based GIS System to Provide Information for Pavement Maintenance Decision-Making DECEMBER Table of Contents Section 1. Pavement Management Plan Executive Summary

Texas at Austin, University of

422

Although most Minnesota airports do not have much concrete pavement, the con-  

E-print Network

Although most Minnesota airports do not have much concrete pavement, the con- crete they do have are generally constructed out of concrete that is much thicker. Maintaining any section of pavement, regardless of its size, is important for pre- serving its condition and optimizing pave- ment life. Pavement

Minnesota, University of

423

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 pavement types. Costs were calculated for one mile in one direction for initial construction and for the maintenance activities anticipated over a 50-year life span for each of the pavement types under consideration

424

Response of desert pavement to seismic shaking, Hector Mine earthquake, California, 1999  

E-print Network

Response of desert pavement to seismic shaking, Hector Mine earthquake, California, 1999 P. K. Haff characteristic surface disturbances on nearby desert pavements. These disturbances included (1) zones of wholesale gravel displacement interspersed with zones of intact pavement, (2) displaced and rotated cobbles

Ahmad, Sajjad

425

EVALUATION OF THE PAVEMENT STRUCTURAL CONDITION AT NETWORK LEVEL USING FALLING WEIGHT  

E-print Network

EVALUATION OF THE PAVEMENT STRUCTURAL CONDITION AT NETWORK LEVEL USING FALLING WEIGHT DEFLECTOMETER agencies to improve the surface condition of pavements, but these measures have not successfully prevented the problem from reoccurring. As a result, the overall pavement condition keeps deteriorating because

Manuel, Lance

426

FREE-FORM ANISOTROPY: A NEW METHOD FOR CRACK DETECTION ON PAVEMENT SURFACE IMAGES  

E-print Network

FREE-FORM ANISOTROPY: A NEW METHOD FOR CRACK DETECTION ON PAVEMENT SURFACE IMAGES Tien Sy NGUYEN(1, in the segmentation step, for crack detection on road pavement images. Features which are calculated along every free on some samples of different kinds of pavements. Results of the method are also given on other kinds

Paris-Sud XI, Université de

427

PRESERVING THE LONG LIFE CONCRETE PAVEMENT NETWORK OF THE WASHINGTON STATE DEPARTMENT OF TRANSPORTATION  

E-print Network

PRESERVING THE LONG LIFE CONCRETE PAVEMENT NETWORK OF THE WASHINGTON STATE DEPARTMENT The Washington State Department of Transportation (WSDOT) has about 2,360 lane miles of concrete pavements of these pavements combined with what WSDOT has learned in the intervening 40-50 years gives a high level

428

PRECAST REPLACEMENT OF CONCRETE PAVEMENT SLABS (Tollway) Effective: March 30, 2009  

E-print Network

PRECAST REPLACEMENT OF CONCRETE PAVEMENT SLABS (Tollway) Effective: March 30, 2009 Revised: October 19, 2012 DESCRIPTION. This work shall consist of the removal of existing concrete pavement, restoration of the subbase material, the installation of precast concrete pavement slabs in accordance

429

Do et al. 1 Full Scale Tests for the Assessment of Wear of Pavement Surfaces  

E-print Network

Do et al. 1 Full Scale Tests for the Assessment of Wear of Pavement Surfaces Minh-Tan Do subjected to heavy traffic. Reports can be found in (1)(2). Evolution of pavements during its whole service shown in the figure 2. By this way, during tests on one track, pavement construction can be carried out

Boyer, Edmond

430

The clogging behaviour and treatment efficiency of a range of porous pavements  

Microsoft Academic Search

This paper presents the findings of a laboratory investigation into the clogging behaviour of three different porous pavements that were most representative of the available range and their pollutant removal efficiency over time. These pavements were monolithic Porous Asphalt (PA), Permapave (PP), and modular Hydrapave (HP). The pavements were dosed with a semi-synthetic stormwater mixture over a continuous period of

C. F. Yong; A. Deletic; T. D. Fletcher; M. R. Grace

431

Recycling seal-coat pavements with self-cementing fly ash. Phase 2, final report  

Microsoft Academic Search

The study evaluated the feasibility of recycling existing chip-seal pavements through stabilization with self-cementing fly ash. It was proposed that an existing pavement could be pulverized in place, sufficient quantities of Class C fly ash added, and the resulting mixture be compacted, providing a stabilized base having greater support capacity than the original pavement section. The Phase II program expanded

1989-01-01

432

Video Conference Agenda and Meeting Notes: Two-Lift Concrete Pavements 27 June 2007  

E-print Network

Video Conference Agenda and Meeting Notes: Two-Lift Concrete Pavements 27 June 2007 Location: FHWA Pavement Technology Center 10:25 am History of Two-Lift Construction in the US Dr. James Cable 10:45 am European Experience with Two-Lift Pavement Construction Dr. Hermann Sommer 11:30 am Two-Lift Construction

433

Nondestructive pavement evaluation technique using falling weight deflectometer  

SciTech Connect

An analytical method to predict the mechanical properties of a multi-layer pavement structure is presented. The development of the model is based on a modified back calculation model, using a finite circular plate resting on an elastic layered system. The deflection of the pavement under the dynamic action of the falling weight deflectometer (FWD) is taken as a function of the load action and the characteristic strength of the layers comprising the system including the friction between the individual layers. The responses of the pavement during the impact loading of the falling weight are measured and analyzed to predict the stress, strain and coefficient of friction between the layers making the system. The results revealed that the model which incorporates the interface of friction coefficient in the back-analysis technique allows for a more accurate calculation of the mechanical properties of the pavements and thus can be used as a quality control to assess the state of adhesion between the pavement layer system.

Al-Nageim, H.; Al-Hakim, B.; Lesley, L. [John Moores Univ., Liverpool (United Kingdom). School of the Built Environment

1996-11-01

434

Urban evaporation rates for water-permeable pavements.  

PubMed

In urban areas the natural water balance is disturbed. Infiltration and evaporation are reduced, resulting in a high surface runoff and a typical city climate, which can lead to floods and damages. Water-permeable pavements have a high infiltration rate that reduces surface runoff by increasing the groundwater recharge. The high water retention capacity of the street body of up to 51 l/m(2) and its connection via pores to the surface lead to higher evaporation rates than impermeable surfaces. A comparison of these two kinds of pavements shows a 16% increase in evaporation levels of water-permeable pavements. Furthermore, the evaporation from impermeable pavements is linked directly to rain events due to fast-drying surfaces. Water-permeable pavements show a more evenly distributed evaporation after a rain event. Cooling effects by evaporative heat loss can improve the city climate even several days after rain events. On a large scale use, uncomfortable weather like sultriness or dry heat can be prevented and the urban water balance can be attenuated towards the natural. PMID:20818060

Starke, P; Göbel, P; Coldewey, W G

2010-01-01

435

MONITORING OF ARTIFICIAL DEFECTS WITHIN A PAVEMENT STRUCTURE WITH A NDT METHOD BASED ON A MECHANICAL IMPACT  

E-print Network

MONITORING OF ARTIFICIAL DEFECTS WITHIN A PAVEMENT STRUCTURE WITH A NDT METHOD BASED-destructive testing (NDT) method used to monitor a pavement structure which contains artificial defects. A 25 m long pavement section has been built on the full scale accelerated pavement testing facility of IFSTTAR

Boyer, Edmond

436

SOURCE: UNIVERSITY OF CALIFORNIA PAVEMENT RESEARCH CENTER FIGURE 1 Moisture-induced stripping in asphalt treated base layer  

E-print Network

SOURCE: UNIVERSITY OF CALIFORNIA PAVEMENT RESEARCH CENTER FIGURE 1 Moisture-induced stripping in asphalt treated base layer PAVEMENT TECHNOLOGY UPDATE This Technology Transfer Program publication is provided by the University of California Pavement Research Center. The University of California Pavement

California at Berkeley, University of

437

Design of a flexible high performance quadcopter platform breaking the MAV endurance record with laser power beaming  

Microsoft Academic Search

In this paper we present the design of a highly flexible quadcopter platform and the software tools used in an example experiment to show unlimited flight time of an MAV with laser power beaming. We describe the mechanical design as well as the flight control system architecture which are focused on easy adaption to a wide variety of experiments. The

Michael C. Achtelik; Jan Stumpf; Daniel Gurdan; Klaus-Michael Doth

2011-01-01

438

Flexibility Program  

ERIC Educational Resources Information Center

These brief guidelines for a muscular flexibility program state that the purpose of such a program is to increase the range of motion in order to avoid injuries and eliminate awkwardness in physical activities. A flexibility program is described as an extension of the warm-up period and should be an ongoing, permanent effort to lengthen muscles. A…

Connors, G. Patrick

439

Evaluation of multilayered pavement structures from measurements of surface waves  

USGS Publications Warehouse

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

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

2006-01-01

440

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

441

Using the Multi-Depth Deflectometer to study pavement response  

E-print Network

the permanent deformation behavior and the state of stress in the modeled pavement layer. This three-dimensional 0 ( F E. J AJ J L )~r SUBGRADE SIMULATED BY 660 MECHANO - LA'TTICE UNITS MODIFIED BY INFLUENCE FACTORS ~ 9000LD (60 kN ) WHEEL PATH... the permanent deformation behavior and the state of stress in the modeled pavement layer. This three-dimensional 0 ( F E. J AJ J L )~r SUBGRADE SIMULATED BY 660 MECHANO - LA'TTICE UNITS MODIFIED BY INFLUENCE FACTORS ~ 9000LD (60 kN ) WHEEL PATH...

Yazdani, Jamshed Iqbal

2012-06-07

442

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

443

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

444

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

445

Comparative Occupational Survey of Civilian and Military Members in the Pavements Maintenance and Construction Equipment Operator Specialties. Final Report for Period 1 October 1975-30 October 1977.  

ERIC Educational Resources Information Center

A study was conducted to analyze and compare the job performance of civil service and military pavements maintenance workers and construction equipment operators. A military sample of 2,675 and a civilian sample of 1,974 were surveyed by means of a job inventory checklist and relative time spent rating method. Of the three job types that were…

Cowan, Douglas K.

446

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

Microsoft Academic Search

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

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

1992-01-01

447

Assessment of secondary materials for pavement construction: Technical and environmental aspects  

SciTech Connect

Current research at the University of Nottingham to enable the use of secondary materials in road construction covers technical aspects, mechanical properties of waste materials and the environmental implications of their use. Materials studied are minestone, china clay sand, slate waste, pulverized fuel ash and furnace bottom ash. The laboratory program set up for this research and the methodologies suggested for the study of the properties of these materials are presented. The test methods currently used to select pavement aggregates are presented along with current methods for the assessment of the environmental impact of secondary aggregates. The potential of the secondary aggregates is assessed within the current technical and environmental procedures previously presented. Two new methodologies are presented, one for the mechanical examination of secondary aggregates and one for the environmental assessment. The mechanical assessment encompasses conventional characterization and classification tests on both unbound and lightly treated pavement materials, and fundamental tests such as repeated load triaxial tests (RLTT) and repeated load indirect tensile tests (RLITT). Some sample results are presented, suggesting the feasibility and adequacy of this methodology for material discrimination, and evaluation of mechanical properties for design purposes. The environmental assessment indicates how the leaching concentration of contaminants from intensive testing can be used as the first step in assessing the environmental acceptability of a secondary material, and the means of determining a more realistic measure of in situ performance is discussed. The advantages and advancements of the presented methodologies over the basic and inappropriate techniques currently used to assess the suitability of secondary aggregates for use as pavement construction materials are discussed.

Nunes, M.C.M. [Univ. of Nottingham (United Kingdom). Dept. of Civil Engineering] [Univ. of Nottingham (United Kingdom). Dept. of Civil Engineering; [National Lab. of Civil Engineering, Lisbon (Portugal); Bridges, M.G.; Dawson, A.R. [Univ. of Nottingham (United Kingdom). Dept. of Civil Engineering] [Univ. of Nottingham (United Kingdom). Dept. of Civil Engineering

1996-12-31

448

Use of noncontact sensors for paving operations on airport pavements  

NASA Astrophysics Data System (ADS)

The Swedish National Road Administration has been using a laser range finder system for assessing longitudinal and transversa profiles of pavements for a number of years. The Civil Administration has expressed interest in trying automated methods for surveying airfield runways. Regardless of sampling method, the data re used as input for computer aided design of new pavement surfaces. Typically, the output will consist of tables and maps of where to pave and mill the old pavement surface. Adjusting an old surface to perfectly smooth standards may require continuously changing the new pavement layer thickness. Traditionally, this was often carried out with mechanical devices, usually in direct touch with a wire. Some manufacturers now offer non-contact devices for pavers such as ultra sound sensors as an alternative to the mechanical sensors thus eliminating the need for setting up sires. The method was tested in late 1997 after the output data were converted for a design to be read directly by a paver control unit. A larger test was done in the summer of 1998. The results were promising and the Royal Swedish Fortifications Administration decided to try the method on a taxiway in 1999. The present paper describes some of the experiences obtained with this method and computer controlled equipment in general.

Lenngren, Carl A.

1999-01-01

449

Salt Frost Deterioration in Concrete Pavement --Causes and Mitigation  

E-print Network

Salt Frost Deterioration in Concrete Pavement --Causes and Mitigation Zhichao Liu, Will Hansen not be accommodated within the pore system. Thus, a net expansion occurs. Joint Deterioration Frost Deterioration Model ·The cryogenic suction pump is a major factor in salt frost damage as it provides additional pore

450

Surface Loading of a Multilayered Viscoelastic Pavement: Semianalytical Solution  

E-print Network

response of a linear viscoelastic pavement. The material parameters of the asphalt concrete are characterized by the relaxation modulus and creep compliance, which are further represented by the Prony series modulus and creep compliance are used simultaneously, instead of only one parameter in the conventional

Pan, Ernie

451

Permeable Interlocking Concrete Pavement (PICP) for Stormwater Management  

E-print Network

Recharge Capacity When Frozen · No Standing Water or Black Ice Development During Winter Weather Conditions Soil Stabilization and Erosion Control Required to Prevent Clogging Cost & Maintenance Total Project Cost Can Be Comparable for PICP with Reduced Stormwater Infrastructure VS. Standard Pavement

452

Roads to Development: Experimental Evidence from Urban Road Pavement  

E-print Network

pavement provision in Mexico. Our findings show that homes in streets that were paved increased their value capita expenditures, increased motor vehicle ownership and were more likely to have made home infrastructure in observational data can be misleading (Duflo and Pande, 2007). Paraphrasing Van de Walle (2002

Silver, Whendee

453

Evaluation of cold planers for grinding PCC pavements  

Microsoft Academic Search

Attempts by two contractors to use cold planing equipment to restore riding quality to faulted PCC pavements are reported. It was found that while the equipment could remove substantially all faulting and greatly improved riding quality, there was severe damage to the concrete adjacent to random cracks and transverse joints in spite of condiderable effort to prevent it. Because of

B. F. Neal; J. H. Woodstrom

1978-01-01

454

Texas Perpetual Pavements: Experience Overview and the Way Forward.  

National Technical Information Service (NTIS)

Since 2001, the State of Texas has been designing and constructing perpetual pavements on some of its heavily trafficked highways where the expected 20-year truck-traffic estimate of 18 kip ESALs is in excess of 30 million. To date, there are 10 in-servic...

L. F. Walubita, T. Scullion, W. Liu

2010-01-01

455

RESEARCH REPORT 1250-1 EFFECT OF RECLAIMED ASPHALT PAVEMENT  

E-print Network

with the Federal Highway Administration. 16. Abstract While the use of reclaimed asphalt pavement (RAP) in asphalt system has prompted a need for specific Superpave guidelines for the use of RAP. In this study asphalts. The result of this study is a methodology for determining the effect of RAP on rheological

Texas at Austin, University of

456

AREA UNDER TREES BETWEEN HOUSES AND EDGE OF PAVEMENT ON ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

AREA UNDER TREES BETWEEN HOUSES AND EDGE OF PAVEMENT ON THE EAST SIDE OF SOUTH JEFFERSON STREET FROM SOUTHEAST CORNER OF INTERSECTION OF SOUTH JEFFERSON STREET AND HIGHLAND AVENUE - South Albany Historic District, Bounded by South Jefferson Street, Highland Avenue & Whitney Avenue, Albany, Dougherty County, GA

457

Desert pavement morphology and dynamics, Big Bend National Park, Texas  

E-print Network

Desert pavements consist of a one- to two-layer thick surface armory of stones overlying finer, virtually stone-free material which often adopts the appearance of a meticulously tiled mosaic. They cover half of the arid land surface in North America...

Harmon, Courtney Michelle

2009-05-15

458

Alternative aircraft loading index for pavement structural analysis  

SciTech Connect

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

Loizos, A.; Charonitis, G. [National Technical Univ. of Athens (Greece)] [National Technical Univ. of Athens (Greece)

1999-05-01

459

SORPTIVITY-BASED SERVICE LIFE PREDICTIONS FOR CONCRETE PAVEMENTS  

E-print Network

in their mixture proportions during the last decade. The use of pozzolans such as silica fume, fly ash, and slag is now commonplace, with many state DOTs progressing to ternary blends (cement, silica fume, and fly ashSORPTIVITY-BASED SERVICE LIFE PREDICTIONS FOR CONCRETE PAVEMENTS by Dale P. Bentz, Mark A. Ehlen

Bentz, Dale P.

460

Graded Viscoelastic Approach for Modeling Asphalt Concrete Pavements  

E-print Network

of the pavement and decrease rapidly with depth from the surface. Most of the literature to date has focused on use of layered-elastic models for the consideration of age stiffening. In the current work, a graded the temperature variation in the asphalt concrete overlay. Dynamic Modulus, E* (GPa) 5 10 15 FIGURE 1. Aged

Paulino, Glaucio H.

461

Alternative modeling framework for pervious concrete pavement condition analysis  

Microsoft Academic Search

Pervious concrete pavement (PCP) is listed as one of the best stormwater management practices by the Environmental Protection Agency (EPA) due to its capacity to reduce impervious areas, capability to improve water quality, reduce runoff quantity, eliminate the need for detention basins, protect downstream channels, and reduce flooding (save lives and properties). Moreover, it is designated a “Green Asset” since

Amir Golroo; Susan L. Tighe

2011-01-01

462

Field Manual for Crack Sealing in Asphalt Pavements  

E-print Network

Research Project 0-4061-P3 Comparison of Hot-Poured Crack Sealant to Emulsified Asphalt Crack Sealant-4061 Comparison of Hot-Poured Crack Sealant to Emulsified Asphalt Crack Sealant Product Number 3 Field Manual, Emulsified Crack Sealants, Asphalt Pavements No. of Pages: 16 Disclaimers Authors' Disclaimer: The contents

Texas at Austin, University of

463

The environmental influence of asphalt pavement and countermeasures  

Microsoft Academic Search

To asphalt pavement, because asphalt is polymer materials, the aging of asphalt cannot be ignored; bituminous mixture is made up of asphalt and aggregate, meanwhile it contains interior pore space. Because of the rheology behaviour of bituminous, bituminous mixture will emerge viscous-plastic deformation under traffic load, and because of the porous in it, the water which enters the pore will

Qingguo Yang; Jincheng Ning

2011-01-01

464

Measurement and effects of segregated hot mix asphalt pavement  

Microsoft Academic Search

Asphalt mixture segregation is the nonuniform distribution of coarse and fine aggregate components. Because of segregation, early distress of asphalt pavement results. A test that identifies asphalt mixture segregation would be a significant contribution to asphalt technology.^ There are several factors that lead to segregation. Segregation can occur during stockpiling and handling of aggregate, and during mixing, storage, transport, and

Ronald Christopher Williams

1996-01-01

465

Fabrication of high performance Pt counter electrodes on conductive plastic substrate for flexible dye-sensitized solar cells  

Microsoft Academic Search

Pt counter electrodes (CEs) with different platinum loading have been prepared using chemical reduced method on flexible indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) for dye-sensitized solar cells (DSSCs). H2PtCl6·6H2O terpineol solutions were screen printed on the transparent ITO-PEN substrates. After drying, H2PtCl6 was reduced by treating it in NaBH4 solution followed by the hydrothermal treatment at 100°C. The obtained

Lili Chen; Weiwei Tan; Jingbo Zhang; Xiaowen Zhou; Xiaoling Zhang; Yuan Lin

2010-01-01

466

Enhancing the resolution of gpr spectra for pavement engineering applications  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation and detects the reflected signals from subsurface structures. It can detect objects, changes in material, and voids and cracks. GPR has many applications in a number of fields. In the field of civil engineering one of the most advanced technologies used for road pavement monitoring is based on the deployment of advanced GPR systems. One of the most relevant causes of road pavement damage is often referable to water intrusion in structural layers. In this context, GPR has been recently proposed as a method to estimate moisture content in a porous medium without preventive calibration. Hence, the development of methods to obtain an estimate of the moisture content is a crucial research field involving economic, social and strategic aspects in road safety for a great number of public and private Agencies. In particular, a recent new approach was proposed to estimate moisture content in a porous medium basing on the theory of Rayleigh scattering, showing a shift of the frequency peak of the GPR spectrum towards lower frequencies as the moisture content increases in the soil. The weakness characterizing this approach is represented by the needs of high resolution signals, whereas GPR spectra are affected by low resolution. Hence, the rising requirement for high resolution leads to specific demands for improved prediction methods. Recently, a new technique combining the response of the conventional fast Fourier transform (FFT, well known for its high-precision receiving signal level) with that of the MUSIC (multiple signal classification) algorithm, well known for its super-resolution capacity has been proposed. This combined method has been proved to obtain a high precision level in quantifying the shift of the frequency peak of the GPR spectrum. This combined method can perform a reliable coarse estimate of the (abscissa of the) frequency peak. Unfortunately, whereas resolution affecting the GPR spectra has been enhanced, we still need a sensible increasing of the moisture content to appreciate a visible frequency shift. Hence, sub-sample resolution techniques are needed to obtain a resolution better than the sample period. Addressing some of these issues, this work proposes a sub-sample resolution technique exploiting a fast parabolic interpolator, running on three samples of the GPR spectrum in the neighborhood of the frequency peak (i.e. the coarse estimation). More in details, the new detector searches for the (abscissa of the) vertex of the parabola fitted over three GPR samples: the coarse estimate of the frequency peak, and one sample before and after this estimation. The rationale behind the new fast parabolic approach is as follows. We expect the method to obtain a finer estimation of the (abscissa of the) frequency peak because we are now interpolating a parabola in the neighborhood of the same maximum (i.e the coarse estimate), but with a narrow variance thus increasing the estimation accuracy. No noteworthy increase of computational complexity and processing throughput is required to implement the new approach. In fact, near the totality of the amount of the required computation is due to the former stage (i.e. FFT and/or MUSIC implementation to evaluate the coarse estimate of the frequency peak), and the latter logic (i.e. the interpolation function) is negligible from implementation and computational point of view. Experimental results confirm the effectiveness of the proposed approach to evidence and quantify moisture content in soil. In fact, the proposed sub-sample super resolution technique can resolve a frequency shift in the GPR spectrum even for a corresponding amount of moisture less than 2-3%.

Benedetto, F.; Benedetto, A.

2012-04-01

467

Nondestructive testing of pavements and pavement bases. 1964-March 1980 (citations from the NTIS Data Base). Report for 1964-March 1980  

SciTech Connect

Nondestructive methods for quality assurance of pavements and pavement bases are investigated in these Government-sponsored research reports. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed. (This updated bibliography contains 151 abstracts, 17 of which are new entries to the previous edition.)

Habercom, G.E. Jr.

1980-04-01

468

Solution-processed high-performance flexible 9, 10-bis(phenylethynyl)anthracene organic single-crystal transistor and ring oscillator  

NASA Astrophysics Data System (ADS)

Organic semiconductor of 9, 10-bis(phenylethynyl)anthracene (BPEA) single crystal ribbon with ultra-long length has been prepared by solution drop casting method, where the growth direction was controlled with the seed crystal. The BPEA single crystal ribbon based field-effect transistors show high hole mobility up to 3.2 cm2/V.s, and the inverters exhibited the highest gain of 92. The complex device such as 5-stage ring oscillator consisting of 10 transistors was also constructed on a single crystal ribbon. This straightforward methodology was applied to fabricate plastic transistors on the flexible substrate, showing high performance even after repeatedly bending of 300 times.

Cai, Xiaozhou; Ji, Deyang; Jiang, Lang; Zhao, Guangyao; Tan, Jiahui; Tian, Guofeng; Li, Jingze; Hu, Wenping

2014-02-01

469

3-D flexible nano-textured high-density microelectrode arrays for high-performance neuro-monitoring and neuro-stimulation.  

PubMed

We introduce a new 3-D flexible microelectrode array for high performance electrographic neural signal recording and stimulation. The microelectrode architecture maximizes the number of channels on each shank and minimizes its footprint. The electrode was implemented on flexible polyimide substrate using microfabrication and thin-film processing. The electrode has a planar layout and comprises multiple shanks. Each shank is three mm in length and carries six gold pads representing the neuro-interfacing channels. The channels are used in recording important precursors with potential clinical relevance and consequent electrical stimulation to perturb the clinical condition. The polyimide structure satisfied the mechanical characteristics required for the proper electrode implantation and operation. Pad postprocessing technique was developed to improve the electrode electrical performance. The planar electrodes were used for creating 3-D "Waterloo Array" microelectrode with controlled gaps using custom designed stackers. Electrode characterization and benchmarking against commercial equivalents demonstrated the superiority of the Flex electrodes. The Flex and commercial electrodes were associated with low-power implantable responsive neuro-stimulation system. The electrodes performance in recording and stimulation application was quantified through in vitro and in vivo acute and chronic experiments on human brain slices and freely-moving rodents. The Flex electrodes exhibited remarkable drop in the electric impedance (100 times at 100 Hz), improved electrode-electrolyte interface noise (dropped by four times) and higher signal-to-noise ratio (3.3 times). PMID:24876130

Gabran, S R I; Salam, Muhammad Tariqus; Dian, Joshua; El-Hayek, Youssef; Perez Velazquez, J L; Genov, Roman; Carlen, Peter L; Salama, M M A; Mansour, Raafat R

2014-09-01

470

Piping Flexibility  

NASA Technical Reports Server (NTRS)

A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

1978-01-01

471

Effects of baseline levels of flexibility and vertical jump ability on performance following different volumes of static stretching and potentiating exercises in elite gymnasts.  

PubMed

This study examined the effects of baseline flexibility and vertical jump ability on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) following different volumes of stretching and potentiating exercises. ROM and CMJ were measured after two different warm-up protocols involving static stretching and potentiating exercises. Three groups of elite athletes (10 male, 14 female artistic gymnasts and 10 female rhythmic gymnasts) varying greatly in ROM and CMJ, performed two warm-up routines. One warm-up included short (15 s) static stretching followed by 5 tuck jumps, while the other included long static stretching (30 s) followed by 3x5 tuck jumps. ROM and CMJ were measured before, during and for 12 min after the two warm-up routines. Three-way ANOVA showed large differences between the three groups in baseline ROM and CMJ performance. A type of warm-up x time interaction was found for both ROM (p = 0.031) and CMJ (p = 0.016). However, all athletes, irrespective of group, responded in a similar fashion to the different warm-up protocols for both ROM and CMJ, as indicated from the lack of significant interactions for group (condition x group, time x group or condition x time x group). In the short warm-up protocol, ROM was not affected by stretching, while in the long warm-up protocol ROM increased by 5.9% ± 0.7% (p = 0.001) after stretching. Similarly, CMJ remained unchanged after the short warm-up protocol, but increased by 4.6 ± 0.9% (p = 0.012) 4 min after the long warm- up protocol, despite the increased ROM. It is concluded that the initial levels of flexibility and CMJ performance do not alter the responses of elite gymnasts to warm-up protocols differing in stretching and potentiating exercise volumes. Furthermore, 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance despite an increase in flexibility in these highly-trained athletes. Key PointsThe initial levels of flexibility and vertical jump ability have no effect on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) of elite gymnasts following warm-up protocols differing in stretching and potentiating exercise volumesStretching of the main leg muscle groups for only 15 s has no effect on ROM of elite gymnastsIn these highly-trained athletes, one set of 5 tuck jumps during warm-up is not adequate to increase CMJ performance, while 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance (by 4.6% above baseline), despite a 5.9% increase in flexibility due to the 30 s stretching exercises. PMID:24570613

Donti, Olyvia; Tsolakis, Charilaos; Bogdanis, Gregory C

2014-01-01

472

Effects of Baseline Levels of Flexibility and Vertical Jump Ability on Performance Following Different Volumes of Static Stretching and Potentiating Exercises in Elite Gymnasts  

PubMed Central

This study examined the effects of baseline flexibility and vertical jump ability on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) following different volumes of stretching and potentiating exercises. ROM and CMJ were measured after two different warm-up protocols involving static stretching and potentiating exercises. Three groups of elite athletes (10 male, 14 female artistic gymnasts and 10 female rhythmic gymnasts) varying greatly in ROM and CMJ, performed two warm-up routines. One warm-up included short (15 s) static stretching followed by 5 tuck jumps, while the other included long static stretching (30 s) followed by 3x5 tuck jumps. ROM and CMJ were measured before, during and for 12 min after the two warm-up routines. Three-way ANOVA showed large differences between the three groups in baseline ROM and CMJ performance. A type of warm-up x time interaction was found for both ROM (p = 0.031) and CMJ (p = 0.016). However, all athletes, irrespective of group, responded in a similar fashion to the different warm-up protocols for both ROM and CMJ, as indicated from the lack of significant interactions for group (condition x group, time x group or condition x time x group). In the short warm-up protocol, ROM was not affected by stretching, while in the long warm-up protocol ROM increased by 5.9% ± 0.7% (p = 0.001) after stretching. Similarly, CMJ remained unchanged after the short warm-up protocol, but increased by 4.6 ± 0.9% (p = 0.012) 4 min after the long warm- up protocol, despite the increased ROM. It is concluded that the initial levels of flexibility and CMJ performance do not alter the responses of elite gymnasts to warm-up protocols differing in stretching and potentiating exercise volumes. Furthermore, 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance despite an increase in flexibility in these highly-trained athletes. Key Points The initial levels of flexibility and vertical jump ability have no effect on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) of elite gymnasts following warm-up protocols differing in stretching and potentiating exercise volumes Stretching of the main leg muscle groups for only 15 s has no effect on ROM of elite gymnasts In these highly-trained athletes, one set of 5 tuck jumps during warm-up is not adequate to increase CMJ performance, while 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance (by 4.6% above baseline), despite a 5.9% increase in flexibility due to the 30 s stretching exercises PMID:24570613

Donti, Olyvia; Tsolakis, Charilaos; Bogdanis, Gregory C.

2014-01-01

473

Flexible polyaniline-coated TiO?/SiO? nanofiber membranes with enhanced visible-light photocatalytic degradation performance.  

PubMed

A simple and practical strategy has been developed for preparing polyaniline (PANi) coated TiO2/SiO2 nanofiber membranes by a combination of electrospinning, calcination and in situ polymerization. TiO2/SiO2 (TS) nanofibers are fabricated by electrospinning, followed by calcination. Then they are used as template for in situ polymerization of aniline monomers. SEM images show that PANi nanoparticles thus formed can be densely and uniformly coated on the surface of TS nanofibers. Photocatalytic degradation tests show that the as-prepared nanofiber membranes exhibit enhanced photocatalytic activity for degradation of methyl orange under visible light, which may be due to the synergistic effect of PANi and TiO2. Furthermore, the effect of polymerization time on the morphology and photocatalytic activity of the membrane is investigated. The free-standing membrane is flexible and easy to handle, which is promising for potential applications in photocatalysis and water remediation fields. PMID:24767497

Liu, Zhenyan; Miao, Yue-E; Liu, Mingkai; Ding, Qianwei; Tjiu, Weng Weei; Cui, Xiaoli; Liu, Tianxi

2014-06-15

474

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

475

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

SciTech Connect

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

Not Available

1991-06-01

476

Flexible nanovectors  

Microsoft Academic Search

In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a

Nicola M Pugno

2008-01-01

477

Flexible Flatfoot  

MedlinePLUS

... which the toes and front part of the foot point outward The heel tilts toward the outside and the ankle appears ... persons with flexible flatfoot, include: Pain in the heel, arch, ankle, or along the outside of the foot “Rolled-in” ankle (over-pronation) Pain along the ...

478

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

E-print Network

Penetrating Radar (GPR)[2] Short pulse radar have been used to detect, locate and characterize surface or airborne targets. Application of similar equipment for subsurface exploration has received a lot of attention over last decade. Short pulse radars have... Processor Receiver Circulat /isolat Receiver Signal Processor To Display Unit To Display Unit Antenna EfS7ATfC Pavement surface Pavement Layer 1 Pavement Layer 2 Pavement Layer 3 Fig 1. 2. 1 Monostatic GPR(leftl; Bistatic GPR(rightl The function...

Lau, Chun Lok

2012-06-07

479

Developing a pavement management system using data fusion of physical features.  

E-print Network

??Pavement assessment is still plagued by the expensive and time-consuming distress data collection method. The VOTERS (Versatile Onboard Traffic Embedded Roaming Sensors) project has successfully… (more)

Aleti, Tarun Reddy

2014-01-01

480

Analysis of engineering characteristics of pavement deflection trends  

SciTech Connect

This paper describes analysis of pavement deflection data collected by the Transport Research Laboratory at two experimental road sites in England during 1960--1985. Measurements of Benkelman beam deflections together with records of traffic loading were taken at 6 to 12 month intervals. The analysis investigates the deflection trend as a function of road base material and thickness. The deflection trend was represented by a negative exponential curve form. Engineering aspects of the curve form were extracted and statistically analyzed. The results obtained focus on the dependency of deflection progression on both road base material and thickness, which are shown to act either jointly or singly, depending on the engineering characteristic of the pavement deflection trend.

Kerali, H.R.; Lawrance, A.J. [Univ. of Birmingham (United Kingdom)] [Univ. of Birmingham (United Kingdom)

1999-05-01

481

Vehicle classes for pavement design and capacity analysis  

SciTech Connect

Transportation engineers working in Colorado were aware of a lack of published data at both the local and national level for vehicle classes on urban streets. Such vehicle class breakdowns are necessary for calculating equivalent daily loaded axle (EDLA) values for pavement design and conducting capacity analyses. A technical committee was formed to collect and analyze weekday vehicle class data on urban streets of various types. The major vehicle classes are passenger cars (70-75%), pickups (15-20%), single unit trucks (5-7%); tractor-trailers, buses, and recreational vehicles account for less than 1%. Using these data, a microcomputer spread sheet was set up to calculate EDLA values for pavement design for a range of design year volumes. This vehicle class data is also very useful in highway capacity calculations.

Kubala, J.; Asce, M.; Lalani, N.; O'Connell, R.; Petersen, C.

1986-11-01

482

A relation of measured deflections, pavement performance and soil characteristics  

E-print Network

0 4 0 8 0 ~ 0 0 g VS 8 s cO c o Q 0 g rn 58 g '0 8e 54 I Q g 4 ~~y 8 $d a Cl g 48 n 4e 8 g 4& O O af O W O O C& lO g g IO+ O Ol CQ ol co Cl I gm?~~o age 5 'f 4 4 ?~mo m~~e IOl t/IO + hO Cll W CO g ~ g y g o o o e oa g m e e ee... 0 4 0 8 0 ~ 0 0 g VS 8 s cO c o Q 0 g rn 58 g '0 8e 54 I Q g 4 ~~y 8 $d a Cl g 48 n 4e 8 g 4& O O af O W O O C& lO g g IO+ O Ol CQ ol co Cl I gm?~~o age 5 'f 4 4 ?~mo m~~e IOl t/IO + hO Cll W CO g ~ g y g o o o e oa g m e e ee...

Hanna, Daniel Nelson

2012-06-07

483

TRUCK PERFORMANCE CURVES REFLECTIVE OF TRUCK AND PAVEMENT CHARACTERISTICS  

E-print Network

ABSTRACT The paper utilizes a linearly increasing variable power vehicle dynamics model to develop modeling, vehicle dynamics, roadway design, truck climbing lanes. INTRODUCTION Mannering and Kilareski

Rakha, Hesham A.

484

Winter Performance and Maintenance of Porous Asphalt Pavements  

E-print Network

impacts for new development and reverse impacts in areas with redevelopment. #12;Porous Asphalt Design impacts for new development and reverse impacts in areas with redevelopment. Porous asphalt systems potential salt reduction Design specifications are improving Construction and installation are developing 5

485

Infiltration Through Desert Pavements, Mojave Desert, CA, USA  

NASA Astrophysics Data System (ADS)

Desert pavements consist of a surface layer of closely packed gravel that overlies thin, gravel-poor vesicular A (Av) soil horizon. Pavements are prominent features in arid and semi-arid environments and can be found on a variety of landforms of significantly diverse ages ranging from Holocene to Tertiary. Well-developed Av profiles form distinct and highly structured prismatic peds. These fine-grained, structured soils can exhibit drastically reduced infiltration rates, rendering some localized areas nearly impermeable and greatly impacting soil development, plant and biota diversity, and groundwater recharge. We sought to study how desert pavement development can impact the hydraulic conductivity characteristics in localized areas (order of 10s of cm). Field sites were chosen at the Mojave Natural Preserve, near Kelso Dunes, CA, USA, which has been the location of considerable prior research by the second author. The sites vary by parent material, clay and silt content, surface age, and variable degree of surface clast cover. Transects were chosen that traversed pavement surfaces of variable development (well developed to poorly developed). Hydraulic conductivity was determined with a tension infiltrometer conducted at different tensions and initial water contents (to better estimate the potential for preferential flow). Sites with dry initial conditions were first analyzed at zero tensions to promote inter-ped flow. After allowing soil peds to hydrate and expand, the tests were run again at a range of soil tensions to promote matrix flow. Differences in saturated conductivities (measured and fitted) were attributed to preferential flow around desiccated peds. Soil texture and structure were measured and described, respectively, allowing for the correlation of conductivity functions to soil surface age and physical characteristics.

Young, M. H.; McDonald, E. V.; Caldwell, T. C.; Benner, S. G.

2003-04-01

486

Effects of pavement surface characteristics and textures on skid resistance  

E-print Network

of . Tire Iree-Rolling Miode. Slipping Mode. Drive slin Brake soli Skidding Mode. Field Miithods of Measurinp Skid Resistance Stopping-Distance Method Deceleration M thod. Skid Trailer Method. Pavement Surface Texture Methods of Measuring Texture...EASJJRED ON AGGREGA. 'IES. 85 LIST OI' FIGURES F IGURE Page Friction character istics of tires operating in the brake slip mode. (From reference 3). I'riction characteristics of tires operating in the cornering slip mode. (I'rom reference 3) Percent decrease...

Tomita, Hisao

2012-06-07

487

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

488

A novel method of bitumen extraction from asphalt pavement  

SciTech Connect

A new method of extracting bitumen from asphalt pavement mixtures has been developed which does not require chlorinated or aromatic compounds for solvents. The preferred solvent is cyclohexane (although cyclopentane may be used) at high temperatures and pressures. The new method requires equipment that is less costly than the centrifuge method currently used and takes less time than extractions with Bioact but more time than when chlorocompounds are used.

Houser, T.J. (Western Michigan Univ., Kalamazoo (United States))

1990-07-01

489

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

490

Graded Viscoelastic Approach for Modeling Asphalt Concrete Pavements  

NASA Astrophysics Data System (ADS)

Asphalt concrete pavements exhibit severely graded properties through their thickness due to oxidative aging effects, which are most pronounced at the surface of the pavement and decrease rapidly with depth from the surface. Most of the literature to date has focused on use of layered-elastic models for the consideration of age stiffening. In the current work, a graded viscoelastic model has been implemented within a numerical framework for the simulation of asphalt pavement responses under thermal and mechanical loading. The graded viscoelastic work is extension of the previous work by Paulino and Jin [1], Mukherjee and Paulino [2], and Buttlar et al. [3]. A functionally graded generalized Maxwell model has been used in the development of a constitutive model for asphalt concrete considering aging and temperature gradients. The aging gradient data from laboratory test results reported by Apeagyei [4] is used for obtaining material properties for the graded viscoelastic model. Finite element implementation of the constitutive model incorporates the generalized iso-parametric formulation (GIF) proposed by Kim and Paulino [5], which leads to the graded viscoelastic elements used in this work.

Dave, Eshan V.; Buttlar, William G.; Paulino, Glaucio H.; Hilton, Harry H.

2008-02-01