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N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP REPORT 817 Validation of Guidelines for Evaluating the Moisture Susceptibility of WMA Technologies Amy Epps Martin Edith Arambula Fan Yin Eun Sug Park Texas a&M TransporTaTion insTiTuTe College Station, Texas Subscriber Categories Construction ⢠Materials ⢠Pavements TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2016 www.TRB.org Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research is the most effective way to solve many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide inter- est to highway authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRBâs recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRBâs relationship to the Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists in high- way transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transporta- tion departments and by committees of AASHTO. Topics of the highest merit are selected by the AASHTO Standing Committee on Research (SCOR), and each year SCORâs recommendations are proposed to the AASHTO Board of Directors and the Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the Acad- emies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America NCHRP REPORT 817 Project 09-49B ISSN 0077-5614 ISBN 978-0-309-37506-1 Library of Congress Control Number 2016933355 © 2016 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 copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce 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, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Ralph J. Cicerone is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied committees, task forces, and panels annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.
C O O P E R A T I V E R E S E A R C H P R O G R A M S ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 09-49B by the Texas A&M Transpor- tation Institute, a member of The Texas A&M University System. Dr. Amy Epps Martin, Professor of Civil Engineering at Texas A&M University and Research Engineer with the Texas A&M Transportation Institute, served as the Principal Investigator. Other authors of this report included Dr. Edith Arambula and Dr. Eun Sug Park from the Texas A&M Transportation Institute and Mr. Fan Yin from Texas A&M University. The research team greatly acknowledge the cooperation and assistance provided by the agencies and contrac- tors who gratefully participated in the survey and shared moisture susceptibility data, including Christopher Euler from New York State DOT, Tanya Nash from Florida DOT, Sheila Hines from Georgia DOT, Joe Devol from Washington DOT, David Powers from Ohio DOT, Kenneth Hobson from Oklahoma DOT, Scott Schram from Iowa DOT, Robert Rea from Nebraska DOT, Brett Trautman from Missouri DOT, Michael Standford from Colorado DOT, Steve Saboundjian from Alaska DOT, Jean-Paul Fort from COLAS Inc., Randy West from National Center for Asphalt Technology, and Haifang Wen from Washington State Uni- versity. Gratitude is also extended to Adolfo Portilla and Daniel Furdock from Texas A&M University for their contributions in laboratory testing. CRP STAFF FOR NCHRP REPORT 817 Christopher W. Jenks, Director, Cooperative Research Programs Christopher Hedges, Manager, National Cooperative Highway Research Program Edward T. Harrigan, Senior Program Officer Anthony P. Avery, Senior Program Assistant Eileen P. Delaney, Director of Publications Maria Sabin Crawford, Editor NCHRP PROJECT 09-49B PANEL Field of Materials and ConstructionâArea of Bituminous Materials Kim A. Willoughby, Washington State DOT, Olympia, WA (Chair) E. Ray Brown, Auburn, AL Ravi V. Chandran, Connecticut DOT, Rocky Hill, CT Matthew Corrigan, Federal Highway Administration, Washington, DC Dale S. Decker, Dale S. Decker, LLC, Eagle, CO Stacey D. Diefenderfer, Virginia Transportation Research Council, Charlottesville, VA Syed W. Haider, Michigan State University, East Lansing, MI James L. Horn, Alaska DOT and Public Facilities, Anchorage, AK Rita B. Leahy, California Asphalt Pavement Association, Sacramento, CA Scott A. Schram, Iowa DOT, Ames, IA Dean C. Weitzel, Carson City, NV Jack H. Springer, FHWA Liaison
F O R E W O R D By Edward T. Harrigan Staff Officer Transportation Research Board This report presents validated guidelines proposed for identifying potential moisture suscep- tibility in warm mix asphalt (WMA) during mix design. Thus, the report will be of immediate interest to materials engineers in state highway agencies and the asphalt pavement construction industry. Over the past decade, the use of WMA for asphalt pavement construction has dramatically increased in the United States. WMA is seen as an alternative to hot mix asphalt (HMA), which offers the potential to lower energy demand during production and construction, reduce emis- sions at the plant and the paver, and increase allowable haul distances. However, questions remain about the long-term performance and durability of WMA pavements. One key issue is the moisture susceptibility of WMA pavements. Concerns about WMA moisture suscep- tibility include the possibility that aggregates will be inadequately dried at lower production temperatures and the fact that several WMA technologies introduce additional moisture in the production process. NCHRP Project 9-49, which was completed in 2013, developed guidelines for WMA mix design and quality control to identify and minimize any possibility of moisture susceptibility. The guidelines were presented in NCHRP Report 763 in the form of a flowchart of condition- ing protocols and a choice of different standard test methods and corresponding thresholds that first assess the potential moisture susceptibility of a WMA mix design or field mixture and then recommend remedies to minimize such susceptibility. Specific test thresholds in the guidelines were based on the results of testing of WMA from field projects in Iowa, Montana, New Mexico, and Texas. The objective of NCHRP Project 9-49B was to validate and revise, if necessary, the thresh- olds in the guidelines developed in NCHRP Project 9-49. The research was performed by the Texas A&M Transportation Institute, College Station, Texas. The research was based on a survey of the state DOTs and paving contractors to identify WMA mixtures with available field performance, mix design, and quality assurance data, including wet indirect tensile (IDT) strengths and tensile strength ratios, wet resilient moduli and ratios, and Hamburg wheel tracking parameters. The survey identified 89 field projects with either IDT or Hamburg wheel tracking results. These results were analyzed to validate the thresholds established for the tests in NCHRP Project 9-49. The key practical outcome of the research is a flowchart (Figure 19 in the report) for conditioning and testing WMA laboratory specimens in the mix design process that incorporates the validated thresholds. This report fully documents the research and includes two appendixes.
C O N T E N T S Note: Photographs, figures, and tables in this report may have been converted from color to grayscale for printing. The electronic version of the report (posted on the web at www.trb.org) retains the color versions. 1 Chapter 1 Background 3 Chapter 2 Recent Relevant Literature 5 Chapter 3 Web-Survey Results 8 Chapter 4 Guideline Threshold Validation 12 Chapter 5 Laboratory Experiment and Results 12 Moisture Conditioning Protocols 15 Specimen-Drying Methods 17 Chapter 6 Conclusions and Recommendations 21 References 22 Appendix A Web-Based Survey 27 Appendix B Statistical Analysis Outputs