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Falling weight deflectometer

About: Falling weight deflectometer is a research topic. Over the lifetime, 2082 publications have been published within this topic receiving 20465 citations. The topic is also known as: FWD.


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Book
01 Nov 1992
TL;DR: In this paper, the authors present the theory of pavement design and review the methods developed by several organizations, such as the American Association of State Highway and Transportation Officials (AASHTO), the Asphalt Institute (AI), and the Portland Cement Association (PCA).
Abstract: This is a textbook on the structural analysis and design of highway pavements. It presents the theory of pavement design and reviews the methods developed by several organizations, such as the American Association of State Highway and Transportation Officials (AASHTO), the Asphalt Institute (AI), and the Portland Cement Association (PCA). It can be used for an undergraduate course by skipping the appendices or as an advanced graduate course by including them. The book is organized in 13 chapters. Chapter 1 introduces the historical development of pavement design, the major road tests, the various design factors, and the differences in design concepts among highway pavements, airport pavements, and railroad trackbeds. Chapter 2 discusses stresses and strains in flexible pavements. Chapter 3 presents the KENLAYER computer program, based on Burmister's layered theory, including theoretical developments, program description, comparison with available solutions, and sensitivity analysis on the effect of various factors on pavement responses. Chapter 4 discusses stresses and deflections in rigid pavements due to curling, loading, and friction, as well as the design of dowels and joints. Influence charts for determining stresses and deflections are also presented. Chapter 5 presents the KENSLABS computer program, based on the finite element method, including theoretical developments, program description, comparison with available solutions, and sensitivity analysis. Chapter 6 discusses the concept of equivalent single-wheel and single-axle loads and the prediction of traffic. Chapter 7 describes the material characterization for mechanistic-empirical methods of pavement design including the determination of resilient modulus, fatigue and permanent deformation properties, and the modulus of subgrade reaction. Chapter 8 outlines the subdrainage design including general principles, drainage materials, and design procedures. Chapter 9 discusses pavement performance including distress, serviceability, skid resistance, nondestructive testing, and the evaluation of pavement performance. Chapter 10 illustrates the reliability concept of pavement design in which the variabilities of traffic, material, and geometric parameters are all taken into consideration. A probabilistic procedure, developed by Rosenblueth, is described and two probabilistic computer programs including VESYS for flexible pavements and PMRPD for rigid pavements are discussed. Chapter 11 outlines an idealistic mechanistic method of flexible pavement design and presents in detail the AI method and the AASHTO method, as well as the design of flexible pavement shoulders. Chapter 12 outlines an idealistic mechanistic method of rigid pavement design and presents in detail the PCA method and the AASHTO method. The design of continuous reinforced concrete pavements and rigid pavement shoulders is also included. Chapter 13 outlines the design of overlay on both flexible and rigid pavements including the AASHTO, AI, and PCA procedures. An Author Index and a Subject Index are provided.

2,667 citations

Journal ArticleDOI
TL;DR: The proposed neuro‐fuzzy model showed good generalization capability, and the evaluation of the model performance produced satisfactory results, demonstrating the efficiency and potential of these new mathematical modeling techniques.
Abstract: : Government agencies and consulting companies in charge of pavement management face the challenge of maintaining pavements in serviceable conditions throughout their life from the functional and structural standpoints. For this, the assessment and prediction of the pavement conditions are crucial. This study proposes a neuro-fuzzy model to predict the performance of flexible pavements using the parameters routinely collected by agencies to characterize the condition of an existing pavement. These parameters are generally obtained by performing falling weight deflectometer tests and monitoring the development of distresses on the pavement surface. The proposed hybrid model for predicting pavement performance was characterized by multilayer, feedforward neural networks that led the reasoning process of the IF-THEN fuzzy rules. The results of the neuro-fuzzy model were superior to those of the linear regression model in terms of accuracy in the approximation. The proposed neuro-fuzzy model showed good generalization capability, and the evaluation of the model performance produced satisfactory results, demonstrating the efficiency and potential of these new mathematical modeling techniques.

128 citations

Journal ArticleDOI
TL;DR: In this article, the characteristics and performance of dry and wet recycled concrete aggregate (RCA) as base and subbase materials for concrete pavement were investigated in terms of the moisture-density relationship, particle index, and fine aggregate angularity.
Abstract: This research presents the test results of a laboratory and field study performed to investigate the characteristics and performance of dry and wet recycled concrete aggregate (RCA) as base and subbase materials for concrete pavement. The physical properties of the RCA were investigated in terms of the moisture-density relationship, particle index, and fine aggregate angularity. Performance concerns have focused on compactibility, stability, shear resistance, and particle breakage of the RCA. These were evaluated in the laboratory using the U.S. Army Corps of Engineers Gyratory Testing Machine. The falling weight deflectometer was used to measure the deflection of pavement sections constructed with RCA base and subbase in the subbase material and may be comparable to crushed stone aggregate.

127 citations

Journal ArticleDOI
TL;DR: In this article, a 3D finite element (FE) model was developed to investigate the dynamic responses of thin, flexible pavement under impulsive loading similar to a falling weight deflectometer test.
Abstract: A three-dimensional (3-D) finite element (FE) model was developed to investigate the dynamic responses of thin, flexible pavement under impulsive loading similar to a falling weight deflectometer test. The FE model simulated the hot-mix asphalt (HMA) surface layer as a linear viscoelastic material and considered the cross-anisotropic stress dependent modulus for the unbound base layer. Implicit dynamic analysis was used to consider the effect of inertia on pavement structural responses. Using two thinpavement structures of different HMA layer thicknesses, 76 and 127 mm, the study analyzed the effects of cross-anisotropic stress-dependent aggregate base modulus and dynamic analysis on pavement responses, including surface deflection, tensile strain at the bottom of the HMA layer, deviator stress in the base layer, and compressive strain on top of the subgrade. Results showed that use of the cross-anisotropic stress-dependent modulus for the unbound base layer resulted in greater predicted pavement response...

111 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive laboratory experimental program was conducted on compacted layers of silty clay, clayey silt, cement-treated clay, sand, gravel, recycled asphalt pavement, and limestone aggregates.
Abstract: The objective of this paper is to assess the potential use of the geogauge and the light falling weight deflectometer (LFWD) as quality control/quality assurance ( QC ∕ QA ) devices for testing subgrades, base courses, and compacted soil layers. A comprehensive laboratory experimental program was conducted on compacted layers of silty clay, clayey silt, cement-treated clay, sand, gravel, recycled asphalt pavement, and limestone aggregates. The geogauge, LFWD, static plate load test (PLT), and the dynamic cone penetration (DCP) measurements were acquired for the constructed layers. The geogauge elastic modulus and the LFWD dynamic modulus were correlated with the PLT initial and reloading elastic moduli and with the DCP penetration rates. The results of this study show that the geogauge and the LFWD can be used to calculate the elastic modulus/stiffness characteristics of compacted layers. Whereas the geogauge and the LFWD determined the initial modulus of the cement-treated clay, they did not yield accura...

110 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202344
202293
202160
202065
201951
201867