Use Of Falling Weight Deflectometer Data For Assessing Pavement Structural Evaluation Values
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Use Of Falling Weight Deflectometer Data For Assessing Pavement Structural Evaluation Values
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Author : Tanveer Chowdhury
language : en
Publisher:
Release Date : 1999
Use Of Falling Weight Deflectometer Data For Assessing Pavement Structural Evaluation Values written by Tanveer Chowdhury and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Pavements categories.
Structural evaluation can be very useful at the network level for project prioritization purposes. In the project priority ranking procedure of the Kansas Department of Transportation (KDOT), a pavement rating attribute, Pavement Structural Evaluation (PSE), is used. These ratings are subjective. his study outlines an approach based on the classical multiple regression analysis resulting in a better estimation of the PSE values using the results from the Falling Weight Deflectometer (FWD) tests and network-level distress survey. The regression models proposed in this study predict the decrease in PSE values by taking into account the FWD data, age, thickness, and distress levels of pavements, and very closely approximate the current PSE ratings obtained at the district level.
Use Of Falling Weight Deflectometer Data For Assessing Pavement Structural Evaluation Values
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Author : Mustaque Hossain
language : en
Publisher:
Release Date : 1999
Use Of Falling Weight Deflectometer Data For Assessing Pavement Structural Evaluation Values written by Mustaque Hossain and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with categories.
Use Of Falling Weight Deflectometer Multi Load Data For Pavement Strength Estimation
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Author : Y. Richard Kim
language : en
Publisher:
Release Date : 2002
Use Of Falling Weight Deflectometer Multi Load Data For Pavement Strength Estimation written by Y. Richard Kim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Pavements categories.
The objective of this study is to develop a mechanistic-empirical method for assessing pavement layer conditions and estimating the remaining life of flexible pavements using multi-load level Falling Weight Deflectometer (FWD) deflections. A dynamic finite element program, incorporating a stress-dependent soil model, was developed to generate the synthetic deflection database. Based on this synthetic database, the relationships between surface deflections and critical pavement responses, such as stresses and strains in each individual layer, have been established. A condition assessment procedure for asphalt pavements that uses multi-load level FWD deflections has been developed using these relationships. The verification study was conducted using field data.
Simplified Techniques For Evaluation And Interpretation Of Pavement Deflections For Network Level Analysis
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Author :
language : en
Publisher:
Release Date : 2012
Simplified Techniques For Evaluation And Interpretation Of Pavement Deflections For Network Level Analysis written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Pavements categories.
The objective of this study was to develop an approach for incorporating techniques to interpret and evaluate deflection data for network-level pavement management system (PMS) applications. The first part of this research focused on identifying and evaluating existing techniques, seeking out those that were simple, reliable, and easy to incorporate into current PMS practices, as well as those that produced consistent results. The second part of the research detailed the development of guidelines for the application of recommended techniques and procedures for determining optimum falling weight deflectometer (FWD) test spacing and data collection frequency. While there are many viable techniques available for evaluating the structural capacity of pavements that use FWD for project-level analysis, many of these techniques are time consuming and require an experienced analyst. As a result, using pavement deflection testing for network-level analysis has been limited to date. This guide provides information for the assessment of pavement structural performance for PMS applications. It reflects the general findings presented in the accompanying final report, Simplified Techniques for Evaluation and Interpretation of Pavement Deflections for Network-Level Analysis (FHWA-HRT-12-023).
Use Of Falling Weight Deflectometer Multi Load Level Data For Pavement Strength Estimation
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Author :
language : en
Publisher:
Release Date : 2001
Use Of Falling Weight Deflectometer Multi Load Level Data For Pavement Strength Estimation written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
The objective of this study is to describe a mechanistic-empirical approach to developing an analysis method for assessing pavement layer conditions and estimating the remaining life of flexible pavements using multi-load level Falling Weight Deflectometer (FWD) deflections. A dynamic finite element program, incorporating a stress-dependent soil model, was developed to generate the synthetic deflection database. Based on this synthetic database, the relationships between surface deflections and critical pavement responses, such as stresses and strains in each individual layer, have been established. A condition assessment procedure for pavement layers using multi-load level FWD deflections is presented in this study. The results indicate that the proposed procedure can estimate the base and subgrade layer conditions. However, large variations were observed in the relationships between the DBCI and desg values and the subgrade CBR values for aggregate base pavements. A FWD test with a load of 53 kN or less does not result in any apparent nonlinear behavior of the subgrade in aggregate base pavements. With regard to the condition assessment of the asphalt concrete (AC) layer, the AC layer modulus and the tensile strain at the bottom of the AC layer are found to be better indicators than the deflection basin parameter. The procedures for performance prediction of fatigue cracking and rutting are developed for flexible pavements. The drastically increasing trend in fatigue cracking with time may not be predicted accurately using the proposed procedure. Such trends may be due to the environmental effects and the inconsistent distress measurements. Predicted rut depths using both single and multi-load level deflections show good agreement with measured rut depths over a wide range of rutting potential. However, the procedure using single load level deflections consistently underpredicts the rut depths. This observation demonstrates that the rutting prediction procedure usin.
Structural Evaluation Of Flexible Pavement Using Deflection Basin
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Author :
language : en
Publisher:
Release Date : 1989
Structural Evaluation Of Flexible Pavement Using Deflection Basin written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1989 with categories.
This paper presents a methodology for testing, evaluation and determination of overlay thickness required for a given pavement section. The overlay design procedure presented makes use of some of the recent developments for analysis and design of asphaltic concrete overlays. The evaluation of in-service pavements includes the use of the deflection parameters developed by testing of the existing pavements with known geometry for determining the moduli of various pavement layers and the required overlay thickness. The method utilizes empirical values and VESYS structural subsystem as an integral approach complementary to each other. Six pavement sections across the State of North Carolina were selected for deflection testing. Deflection parameters were developed to characterize the deflection data from these pavement sections. In addition, VESYS structural system was used to develop nomographs for the interpretation of the measured deflection basin parameters. These nomographs were used to backcalculate the layer moduli form deflection parameters and known layer thicknesses using iterative solutions. The backcalculated layer moduli from these nomographs correspond to the climate conditions that happen to exist during the time of testing and must therefore be adjusted to other climatic conditions. A procedure for such an adjustment is also included in the design procedure. Many different methods have been developed for determining an overlay thickness. These methods can be categorized in three groups : component analysis, deflection based, and analytically based. A mechanistic procedure is described in this paper. This procedure is based on the data and findings of a previous research and has been used to evaluate in-service pavements in North Carolina using Falling Weight Deflectometer (FWD) deflection parameters. The procedure includes four major parts : (a) FWD deflection parameters and data collection, (b) back-calculation of layer moduli, (c) adjustment of layer moduli and (d) prediction of overlay thickness. For the covering abstract of this Conference see IRRD abstract number 853851.
Investigation Of The Rolling Wheel Deflectometer As A Network Level Pavement Structural Evaluation Tool
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Author : Brian K. Diefenderfer
language : en
Publisher:
Release Date : 2010
Investigation Of The Rolling Wheel Deflectometer As A Network Level Pavement Structural Evaluation Tool written by Brian K. Diefenderfer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Pavements categories.
The Virginia Department of Transportation (VDOT) currently uses the results of automated surface distress surveys to assist in developing pavement maintenance strategies for its interstate and primary roadways. Totaling nearly 27,000 lane-miles, these roadways consist of flexible, rigid, and composite (flexible over rigid) pavements. These video-based surface distress data consist of quantities of distress that are visible in the pavement surface. Obtaining structural data from falling weight deflectometer (FWD) testing has only recently been implemented at the network level. A growing area of interest in pavements research is developing new and faster technologies that are well suited for nondestructively assessing the pavement structure without causing delays to the traveling public. One recently developed system, the rolling wheel deflectometer (RWD), measures the response from one-half of an 18-kip single-axle load traveling at normal highway speeds. This technology can measure deflections for approximately 200 to 300 lane-miles per day, which is approximately 10 times the production of traditionally used FWD testing. The primary advantages of using RWD are twofold: the testing can be conducted at highway speeds for increased safety, and the loading by the RWD is thought to replicate better the actual dynamic effects on pavements caused by heavy vehicle loading. A potential application might be to use the RWD to pre-screen the pavement network to identify areas where more detailed investigations are needed (e.g., by traditional FWD testing). This report provides the results of RWD testing on three Virginia routes and a comparison of the deflection results obtained with RWD and FWD testing on sections of I-64 and I-81. The RWD provided deflection measurements over long distances at or near highway speeds with minimal interruption to the highway users, and the RWD and FWD deflection results were not well correlated. Further, the standard deviation of the RWD deflection results fluctuated with changes in surface mix type. For these reasons, the study recommends that VDOT not pursue additional RWD testing on roadways that are expected to have low deflection values and are likely to be uniform in structural cross-section (i.e., conditions that might be expected on interstate facilities).
Using Falling Weight Deflectometer Data With Mechanistic Empirical Design And Analysis
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Author : Kurt D. Smith
language : en
Publisher:
Release Date : 2017
Using Falling Weight Deflectometer Data With Mechanistic Empirical Design And Analysis written by Kurt D. Smith and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Pavements categories.
The need to accurately characterize the structural condition of existing pavements has increased with the recent development, release, and ongoing implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG). A number of different material inputs are required in the procedure, and it is important to adequately characterize and define them. The analysis of deflection data collected by the falling weight deflectometer (FWD) provides a quick and reliable way to characterize the properties of the paving layers, as well as to assess the load-carrying capacity of existing pavement structures. With the release of the new MEPDG, there is a pressing need to identify and evaluate the way that FWD testing is integrated into the new design procedure. Moreover, as highway agencies continue to implement the MEPDG, they need best practices guidance on how to effectively test existing pavement structures and interpret the results as part of a mechanistic-empirical pavement evaluation and rehabilitation process.
Assessing The Precision Of Falling Weight Deflectometer For Field Measurements
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Author : B. Choubane
language : en
Publisher:
Release Date : 2006
Assessing The Precision Of Falling Weight Deflectometer For Field Measurements written by B. Choubane and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Nondestructive testing categories.
Deflection-based techniques are being widely used to evaluate the structural integrity and for estimating the elastic moduli of in-service pavements. These deflections can be non-destructively induced and measured using various commercially available devices. In recent years, the Falling Weight Deflectometer (FWD) has gained worldwide acceptance among most highway agencies due to its versatility and ease of use. However, as with any testing using subject-driven, instrumented devices, the major concerns of the end usefulness of the resulting data are accuracy and precision. Although a level of uncertainty is always inherent to any measurement process, it must also be appropriately quantified or assessed. Therefore, the Florida Department of Transportation initiated the present field study to assess the level of precision of FWD measurements on flexible pavements. Deflection data were acquired using three FWD units concurrently on four different asphalt pavement sections. The precision was then addressed in terms of testing repeatability and reproducibility. In addition, the effects of buffer designs on deflection measurements were also evaluated. This paper presents a description of the testing program, data collection efforts, and subsequent analyses and findings. Precision statements for repeatability and reproducibility of field measurements were developed and are summarized herein. A generally high level of repeatability and reproducibility of the deflection measurements is demonstrated.
Pavement Analysis
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Author : Per Ullidtz
language : en
Publisher:
Release Date : 1987
Pavement Analysis written by Per Ullidtz and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1987 with Pavements categories.
This book provides some simple methods for the analysis of pavements in order to describe their present condition and to predict their future condition. Functional and structural conditions of flexible and rigid highway and airfield pavements are treated.