Assessment of Continuous Pavement Deflection Measuring Technologies (2013)

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TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2013 www.TRB.org RepoRt S2-R06F-RW-1 The Second S T R A T E G I C H I G H W A Y R E S E A R C H P R O G R A M Assessment of Continuous Pavement Deflection Measuring Technologies Gerardo Flintsch, samer Katicha, and James Bryce Virginia Tech Transportation Institute Brian Ferne and simon nell Transport Research Laboratory Brian dieFenderFer Virginia Center for Transportation Innovation and Research

Subscriber Categories Construction Highways Maintenance and Preservation Pavements

SHRP 2 Reports Available by subscription and through the TRB online bookstore: www.TRB.org/bookstore Contact the TRB Business Office: 202-334-3213 More information about SHRP 2: www.TRB.org/SHRP2 SHRP 2 Report S2-R06F-RW-1 ISBN: 978-0-309-12960-2 © 2013 National Academy of Sciences. All rights reserved. Copyright Information Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copy- right to any previously published or copyrighted material used herein. The second Strategic Highway Research Program grants permission to repro- duce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, or FHWA endorsement of a particular product, method, or practice. 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Developments in research and technology—such as advanced materials, communications technology, new data collection tech- nologies, and human factors science—offer a new opportunity to improve the safety and reliability of this important national resource. Breakthrough resolution of significant transportation problems, however, requires concentrated resources over a short time frame. Reflecting this need, the second Strategic Highway Research Program (SHRP 2) has an intense, large-scale focus, integrates multiple fields of research and technology, and is fundamentally different from the broad, mission-oriented, discipline-based research programs that have been the mainstay of the highway research industry for half a century. 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SHRP 2 focuses on applied research in four areas: Safety, to prevent or reduce the severity of highway crashes by understanding driver behavior; Renewal, to address the aging infrastructure through rapid design and construction methods that cause minimal disruptions and produce lasting facilities; Reliability, to reduce congestion through incident reduction, management, response, and mitigation; and Capacity, to integrate mobility, economic, environmental, and community needs in the planning and designing of new trans- portation capacity. SHRP 2 was authorized in August 2005 as part of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). The program is managed by the Transportation Research Board (TRB) on behalf of the National Research Council (NRC). 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ACKNOWLEDGMENTS This work was sponsored by the Federal Highway Administration in cooperation with the American Asso- ciation of State Highway and Transportation Officials. It was conducted in the second Strategic Highway Research Program, which is administered by the Transportation Research Board of the National Acad- emies. The project was managed by James Bryant, Senior Program Officer for SHRP 2 Renewal. The authors would like to thank Chuck Taylor of the second Strategic Highway Research Program (SHRP 2), the Project R06F technical expert task group members (Lynne Irwin, Erland Lukanen, Mark McDaniel, Nadarajah Sivaneswaran, Thomas Van, and Tom Warne) for their guidance and informative feedback, the U.K. Highways Agency for access to the HA traffic speed deflectometer measurements, and the U.S. FHWA and Applied Research Associates for the rolling wheel deflectometer data. SHRP 2 STAFF Ann M. Brach, Director Stephen J. Andrle, Deputy Director Neil J. Pedersen, Deputy Director, Implementation and Communications James Bryant, Senior Program Officer, Renewal Kenneth Campbell, Chief Program Officer, Safety JoAnn Coleman, Senior Program Assistant, Capacity and Reliability Eduardo Cusicanqui, Financial Officer Walter Diewald, Senior Program Officer, Safety Jerry DiMaggio, Implementation Coordinator Shantia Douglas, Senior Financial Assistant Charles Fay, Senior Program Officer, Safety Carol Ford, Senior Program Assistant, Renewal and Safety Elizabeth Forney, Assistant Editor Jo Allen Gause, Senior Program Officer, Capacity Rosalind Gomes, Accounting/Financial Assistant Abdelmename Hedhli, Visiting Professional James Hedlund, Special Consultant, Safety Coordination Alyssa Hernandez, Reports Coordinator Ralph Hessian, Special Consultant, Capacity and Reliability Andy Horosko, Special Consultant, Safety Field Data Collection William Hyman, Senior Program Officer, Reliability Michael Marazzi, Senior Editorial Assistant Linda Mason, Communications Officer Reena Mathews, Senior Program Officer, Capacity and Reliability Matthew Miller, Program Officer, Capacity and Reliability Michael Miller, Senior Program Assistant, Capacity and Reliability David Plazak, Senior Program Officer, Capacity Onno Tool, Visiting Professional Dean Trackman, Managing Editor Connie Woldu, Administrative Coordinator Patrick Zelinski, Communications/Media Associate

F O R EWO R D James W. Bryant, Jr., Ph.D., P.E., SHRP 2 Senior Program Officer The measurement of the response of a pavement to an applied load is a critical input for (1) structural analysis of in-service pavements, (2) identification of sections with structural capacity deficiencies at the network level, and (3) design of pavement renewal or rehabilita- tion treatments at the project level. The most widely used method for measuring pavement response to an applied load is the falling weight deflectometer (FWD), which is a time- consuming technology and may not be practical for a network-level structure monitoring. The use of continuous deflection measuring devices, which operate at speeds of 30 to 45 mph in some cases, allows for better spatial coverage with less impact on traffic. This project evaluated current technologies implemented in continuous deflection measuring devices. The objective of this project was to critically assess the potential of existing continuous deflection devices to be practical and cost-effective tools for use in the development of optimum pavement rehabilitation strategies on rapid renewal projects. This assessment included (1) the potential value of and demand for continuous deflection data by transporta- tion agencies; (2) the technical capabilities (including accuracy and repeatability of test results and ability to provide meaningful data), limitations (field applications, equipment configuration, and operating and safety characteristics), and other impediments to imple- mentation of existing devices; and (3) suggestions for improvements to currently available technologies. The main products of the project include a catalogue of existing continuous deflection measuring technologies, detailed assessment of the capabilities of the most-promising devices, case studies illustrating the application of the technology for supporting various pavement management decision-making processes, a fact sheet describing the main technologies identified for continuously measuring pavement deflections and their potential uses, training materials for a workshop on the topic, research needs statements for the most-pressing research identified (provided as an appendix), and a dissemination and implementation plan for this technology. Technologies for continuous deflection measurement are still evolving. This report provides practical examples of how data from these devices can be used for network-level pavement management applications. As budgetary pressures continue to place a high demand of the effective allocation of resources, the ability to isolate areas for more-detailed and “-costly” pavement assessments will become desirable. The data collected by the devices investigated in this study can help a transportation agency ascertain the areas of pavement that need a detailed condition assessment. Demand for this type of technology will continue to increase. Information provided in this report helps to expand the knowledge base of what this technology can do and provides confidence and examples of how the technology can be used.

C O n t E n t s 1 Executive Summary 5 CHAPTER 1 Introduction 5 Objective 5 Critical Research Questions 6 Methodology and Report Overview 8 CHAPTER 2 Research Approach 8 Identification and Assessment of Available Technologies 8 Determination of User Needs 9 Selection of Candidate Devices 9 Data Collection 11 Data Analysis 11 Example Applications 11 Current and Future Developments 12 CHAPTER 3 Analysis and Findings 12 Catalogue of Deflection Measuring Devices 18 Survey of State DOT Practices and Needs 21 Selection of Candidate Devices 25 Detailed Description of the Selected Equipment 29 Phase I Assessment 38 Phase II Assessment 66 Operational Characteristics 74 CHAPTER 4 Example Applications and Recent Developments 74 Example Applications 86 Current and Future Developments 90 CHAPTER 5 Conclusions and Suggested Research 90 Findings 92 Conclusions 92 Recommendations for Implementation 95 References 97 Appendix A. Research Problem Statements