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This report is an archived publication and may contain dated technical, contact, and link information
Publication Number:  FHWA-HRT-16-010    Date:  March 2017
Publication Number: FHWA-HRT-16-010
Date: March 2017


Using Falling Weight Deflectometer Data With Mechanistic-Empirical Design and Analysis, Volume II: Case Study Reports

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This report documents a study conducted to investigate the use of the falling weight deflectometer (FWD) as part of mechanistic-empirical pavement design and rehabilitation procedures incorporated within the Mechanistic-Empirical Pavement Design Guide (MEPDG) developed by the National Cooperative Highway Research Program and subsequently adopted by the American Association of State Highway and Transportation Officials. The first volume of this three-volume report documents general pavement deflection-testing procedures and commonly used deflection analysis approaches and a review of backcalculation programs for flexible, rigid, and composite pavement structures. The relevance of the different procedures and approaches to the MEPDG were explored through examination of six case studies evaluated using FWD testing results in the MEPDG, and the findings are presented here in the second volume. Based on the case study findings and information from the literature, best practice guidelines for effective testing of existing pavement structures and interpretation of those results as part of a mechanistic-empirical pavement evaluation and rehabilitation process were developed and are presented in the third volume. This report is intended for use by pavement engineers as well as researchers involved in rehabilitation design and management of agencies’ pavements.

Cheryl Allen Richter, P.E., Ph.D.
Director, Office of Infrastructure
Research and Development


This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.

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Technical Report Documentation Page

1. Report No.


2. Government Accession No. 3 Recipient's Catalog No.
4. Title and Subtitle

Using Falling Weight Deflectometer Data with Mechanistic-Empirical Design and Analysis, Volume II: Case Study Reports

5. Report Date

March 2017

6. Performing Organization Code
7. Author(s)

James E. Bruinsma, Julie M. Vandenbossche, Karim Chatti, and Kurt D. Smith

8. Performing Organization Report No.


9. Performing Organization Name and Address

Applied Pavement Technology Inc.
115 West Main Street, Suite 400
Urbana, IL 61801

10. Work Unit No. (TRAIS)

11. Contract or Grant No.


12. Sponsoring Agency Name and Address

Federal Highway Administration
1200 New Jersey Ave. SE
Washington, DC 20590-9898

13. Type of Report and Period Covered

Final Report; 10/2006–12/2010

14. Sponsoring Agency Code


15. Supplementary Notes

The FHWA Contracting Officer’s Technical Representative was Nadarajah Sivaneswaran.

16. Abstract

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, best practices guidance is needed on how to effectively test existing pavement structures and interpret the results as part of a mechanistic-empirical pavement evaluation and rehabilitation process.


This document is part of a three-volume report investigating the use of the FWD as part of mechanistic-empirical pavement design and rehabilitation procedures. In this volume, six case studies—flexible pavement, flexible pavement on rubblized portland cement concrete (PCC), rigid pavement on granular base, rigid pavement on stabilized base, rigid pavement on existing flexible pavement, and composite (hot-mix asphalt (HMA) over PCC pavement)—were used to evaluate how FWD deflection data are used in the rehabilitation portion of the MEPDG. The case studies used data from in-service pavements. Specifically, deflection data and backcalculation results were used to characterize the existing HMA, PCC, stabilized and unstabilized bases, and aggregate and subgrade properties in the MEPDG design program. Laboratory testing results were compared with FWD results, and the final designs were found to be relatively insensitive to the differences in characterization of existing layer inputs.


This is volume II of a three-volume report. The other volumes in the series are FHWA-HRT-16-009, Volume I: Final Report, and FHWA-HRT-16-011, Volume III: Guidelines for Deflection Testing, Interpretation, and Analysis.

17. Key Words

Falling weight deflectometer, Backcalculation, Deflection data, Structural evaluation, Resilient modulus, Elastic modulus, Subgrade support, Mechanistic-empirical pavement design, Rehabilitation design, Overlay design

18. Distribution Statement

No restrictions. This document is available through the
National Technical Information Service,
Springfield, VA 22161.

19. Security Classification
(of this report)


20. Security Classification
(of this page)


21. No. of Pages


22. Price


Form DOT F 1700.7 (8-72) Reproduction of completed page authorized




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