Prediction of Remaining Life of Asphalt Pavement with Falling-Weight Deflectometer Multiload-Level Deflections

2003 ◽  
Vol 1860 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Hee Mun Park ◽  
Y. Richard Kim
Keyword(s):  
Flexible Pavements ◽  
Fatigue Cracking ◽  
Pavement Performance ◽  
Falling Weight Deflectometer ◽  
Remaining Life ◽  
Performance Models ◽  
Response Models ◽  
Wide Range ◽  
Pavement Response ◽  
Falling Weight

The development of prediction methods for the remaining life of flexible pavements using falling-weight deflectometer (FWD) multiload-level deflections is presented. Pavement response models and pavement performance models were used in developing this procedure. The pavement response models were designed to predict critical pavement responses from surface deflections and deflection basin parameters. The pavement performance models were used to develop the relationships between critical pavement responses obtained from pavement response models and actual pavement performance. Pavement distress data and FWD multiload-level deflection data obtained from the Long-Term Pavement Performance database were used to verify the performance prediction procedure. It was found that the performance of fatigue cracking can be predicted using the proposed procedure except for pavements with high and rapidly increasing cracking in wet-freeze regions. Such trends may be due to environment-induced distresses such as low-temperature cracking, permanent deformation of unbound layers, or both, during the spring thaw period. Predicted rut depths using both single-load and multiload-level deflections show good agreement with measured rut depths over a wide range of rutting potentials. However, the procedure using single–load-level deflections consistently underpredicts the rut depths. This observation demonstrates that the rutting prediction procedure using multiload-level deflections can estimate an excessive level of rutting quite well and thus improve the prediction quality of rutting potential in flexible pavements.

Prediction of Pavement Remaining Life

1996 ◽  
Vol 1524 (1) ◽  
pp. 137-144 ◽  
Author(s):  
T. S. Vepa ◽  
K. P. George ◽  
A. Raja Shekharan
Keyword(s):  
Data Base ◽  
Management System ◽  
Flexible Pavements ◽  
Information Management System ◽  
Pavement Management ◽  
Remaining Life ◽  
Structural Capacity ◽  
System Data ◽  
Performance Project ◽  
Falling Weight

The evaluation of remaining life is necessary to make optimal use of the structural capacity of in-service pavements. It simply represents the useful life left in the pavement until a failure condition is reached. Knowledge of remaining life facilitates decision making in regard to strategies for reconstruction-rehabilitation of roads, thereby leading to the efficient use of existing resources. Several methods proposed or used by various agencies to estimate the remaining lives of pavements are reviewed. They are classified under two categories: functional and structural. Making use of the Mississippi Department of Transportation pavement management system data base, survivor curves are developed for seven classes of flexible pavements with from thin to thick structures. By using these survivor curves a novel method for estimating remaining life is proposed. The reasonableness of the selected methods is examined by putting them to use in calculating the remaining lives of each of eight rigid and flexible pavement sections, all of them from the Mississippi global positioning system sections of the Strategic Highway Research Program–Long-Term Pavement Performance project (LTPP). With the structural details, falling weight deflectometer deflection data, and the distress information compiled from the LTTP information management system data base, the authors use two and four methods for rigid and flexible pavements, respectively, to determine the remaining lives. The remaining lives calculated by two methods for rigid pavements are comparable. Three of four methods for flexible pavements also generated comparable remaining lives. The authors were encouraged by the results and recommend that the survivor curve approach be explored further for network-level remaining life calculations. The reliabilities of various techniques currently available for the remaining life calculation are discussed.

Direct Method for Evaluating Structural Needs of Flexible Pavements with Falling-Weight Deflectometer Deflections

2003 ◽  
Vol 1860 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Mario S. Hoffman
Keyword(s):  
Direct Method ◽  
Flexible Pavements ◽  
Falling Weight Deflectometer ◽  
Simple Method ◽  
Traffic Demand ◽  
Structural Evaluation ◽  
Overlay Design ◽  
Subgrade Modulus ◽  
Simple Equations ◽  
Falling Weight

A direct and simple method (YONAPAVE) for evaluating the structural needs of flexible pavements is presented. It is based on interpretation of measured falling-weight deflectometer (FWD) deflection basins using mechanistic and practical approaches. YONAPAVE estimates the effective structural number (SN) and the equivalent subgrade modulus independently of the pavement or layer thicknesses. Thus, there is no need to perform boreholes, which are expensive, time-consuming, and disruptive to traffic. Knowledge of the effective SN and the subgrade modulus together with an estimate of the traffic demand allows the determination of the overlay required to accommodate future needs. YONAPAVE’s simple equations can be solved using a pocket calculator, making it suitable for rapid estimates in the field. The simplicity of the method, and its independence from major computer programs, make YONAPAVE suitable for estimating the structural needs of a road network using FWD data collected on a routine or periodic basis along network roads. YONAPAVE can be used with increased experience and confidence as the basis for nondestructive testing structural evaluation and overlay design at the project level.

Dynamic Interpretation for Impulsive Deflection Test on Flexible Pavements

1998 ◽  
Vol 14 (2) ◽  
pp. 91-100
Author(s):  
Der-Wen Chang ◽  
Chia-Ling Chang
Keyword(s):  
Iterative Scheme ◽  
Flexible Pavements ◽  
Falling Weight Deflectometer ◽  
Correction Procedure ◽  
Subgrade Soils ◽  
Forward Analysis ◽  
Dynamic Interpretation ◽  
Equivalent Number ◽  
Deflection Test ◽  
Falling Weight

AbstractIn this study, a computer program DBFWD is developed for data analysis of Falling Weight Deflectometer (FWD) test on flexible pavements. To backcalculate the layer moduli of the pavement, a number of iterative backcalculation schemes were employed with the forward analysis of the Green's flexibility influence functions. The temperature and the moisture influences on material moduli of the asphalt surface and the subgrade soils were considered in the analysis. As the result, the iterative scheme based on the peak deflection ratios was selected to backcalculate the layer moduli of local pavements. Owing to the correction procedure used in the program, interpretations with four original deflections were found more accurate than those with equivalent number of modified deflections. Comparisons of program DBFWD with other static backcalculation programs on theoretical and experimental deflections indicated that dynamic interpretation is more effective in providing the layer modulus information. Despite of the requirements of accurate inputs of the layer thickness and the testing load for the analysis, a generalized application of the program needs to be clarified with model road test in demand.

A practical approach to falling-weight deflectometer (FWD) data reduction

2005 ◽  
Vol 42 (2) ◽  
pp. 641-645 ◽  
Author(s):  
Dieter Stolle ◽  
Peijun Guo
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Falling Weight Deflectometer ◽  
Layer System ◽  
Surface Loading ◽  
Back Calculation ◽  
Pavement Response ◽  
Subgrade Modulus ◽  
Falling Weight

The authors present a simplified methodology for preprocessing falling-weight deflectometer (FWD) data, which identify a pseudo-static pavement response to surface loading. This allows one to employ static analysis to back-calculate the mechanical properties of the pavement–subgrade system. It is shown that the subgrade modulus can be identified, independent of the details of the pavement structure itself, at least for a two-layer system. The quality of the effective shear modulus is sensitive to the value of Poisson's ratio selected.Key words: pavement–subgrade system, subgrade modulus, back-calculation, FWD.

scholarly journals Experimental continuously reinforced concrete pavement parameterization using nondestructive methods

2016 ◽  
Vol 9 (2) ◽  
pp. 263-274
Author(s):  
L. S. Salles ◽  
J. T. Balbo
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Structural Condition ◽  
Concrete Pavement ◽  
Pavement Performance ◽  
Falling Weight Deflectometer ◽  
Matching Process ◽  
Load Transfer Efficiency ◽  
Falling Weight ◽  
The University

ABSTRACT Four continuously reinforced concrete pavement (CRCP) sections were built at the University of São Paulo campus in order to analyze the pavement performance in a tropical environment. The sections short length coupled with particular project aspects made the experimental CRCP cracking be different from the traditional CRCP one. After three years of construction, a series of nondestructive testing were performed - Falling Weight Deflectometer (FWD) loadings - to verify and to parameterize the pavement structural condition based on two main properties: the elasticity modulus of concrete (E) and the modulus of subgrade reaction (k). These properties estimation was obtained through the matching process between real and EverFE simulated basins with the load at the slab center, between two consecutive cracks. The backcalculation results show that the lack of anchorage at the sections end decreases the E and k values and that the longitudinal reinforcement percentage provides additional stiffness to the pavement. Additionally, FWD loadings tangential to the cracks allowed the load transfer efficiency (LTE) estimation determination across cracks. The LTE resulted in values above 90 % for all cracks.

Field Assessment of Changes in Pavement Moduli Caused by Freezing and Thawing

1998 ◽  
Vol 1615 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Da-Tong Jong ◽  
Peter J. Bosscher ◽  
Craig H. Benson
Keyword(s):  
Flexible Pavements ◽  
Complete Recovery ◽  
Meteorological Conditions ◽  
Phase Changes ◽  
Water Phase ◽  
Falling Weight Deflectometer ◽  
Freezing And Thawing ◽  
Field Assessment ◽  
Falling Weight ◽  
Water Contents

Three secondary highways with flexible pavements were instrumented for 18 months to monitor changes in pavement moduli caused by seasonal meteorological changes. Temperatures, water contents, and water phase changes in the subsurface as well as meteorological conditions were recorded every 2 hours throughout the study. Pavement moduli were regularly determined by conducting surveys with a falling weight deflectometer and by performing backcalculations using the program Modulus. The moduli of the base and subgrade typically increased 12 to 4 times, respectively, when frost penetrated the subsurface. When the base and subgrade began to thaw, the moduli decreased substantially. The base moduli decreased the most, typically being about 35 percent of the prefreezing values by the end of thaw. Smaller decreases occurred in the subgrade. The subgrade moduli were about 65 percent of their prefreezing values by the end of thaw. The moduli continued to decrease until thaw was complete and then gradually recovered back to the original prefreezing values. Complete recovery required approximately 4 months. Similar changes in moduli were observed regardless of site or year.

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