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TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2012 www.TRB.org 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 709 Subscriber Categories Highways ⢠Materials Investigation of Short-Term Laboratory Aging of Neat and Modified Asphalt Binders David A. Anderson State College, PA Ramon Bonaquist ADVANCED ASPHALT TECHNOLOGIES, LLC Sterling, VA 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 provides the most effective approach to the solution of 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 develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Boardâs recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of 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 at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 709 Project 09-36 ISSN 0077-5614 ISBN 978-0-309-21363-9 Library of Congress Control Number 2011939877 © 2011 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, FTA, or Transit Development Corporation 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 project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. 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 Governing Board of the National Research Council. 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 Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, 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 is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied activities 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 individu- als interested in the development of transportation. www.TRB.org www.national-academies.org
CRP STAFF FOR NCHRP REPORT 709 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Edward T. Harrigan, Senior Program Officer Melanie Adcock, Senior Program Assistant Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor NCHRP PROJECT 09-36 PANEL Field of Materials and ConstructionâArea of Bituminous Materials Louay N. Mohammad, Louisiana State University, Baton Rouge, LA (Chair) John DâAngelo, DâAngelo Consulting, LLC, Annandale, VA Frank Fee, NuStar Asphalt Refining, LLC, Media, PA Kee Y. Foo, California DOT, Sacramento, CA Gale C. Page, Gainesville, FL Michael Zupanick, Technologic Resources Inc., Broomall, PA John âJackâ Youtcheff, FHWA Liaison Frederick Hejl, TRB Liaison AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 9-36 by Advanced Asphalt Tech- nologies, LLC. Dr. David A. Anderson, P.E., and Dr. Ramon Bonaquist, P.E., served as co-principal inves- tigators for the project. Dr. J. Claine Petersen provided assistance with the chemistry of binder aging, and Dr. Charles Antle provided assistance with experimental design. The report was authored by Drs. Ander- son and Bonaquist. 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
This report provides a proposed method of test for short-term laboratory aging of neat and modified asphalt binders using the Modified German Rotating Flask (MGRF) as an alternative to the Rolling Thin Film Oven Test (RTFOT, AASHTO T 240). Thus, the report will be of immediate interest to staff of state highway agencies, materials suppliers, and paving contractors with responsibility for specification and testing of asphalt binders. NCHRP Project 9-36, âImproved Procedure for Laboratory Aging of Asphalt Binders in Pavements,â was awarded to Advanced Asphalt Technologies, LLC, Sterling, Virginia, with major participation of consultant Dr. David A. Anderson, State College, Pennsylvania. The objective of this research was to develop and validate a proposed procedure for the short-term laboratory aging of asphalt binders usable in a purchase specification such as AASHTO M 320 that (1) applied equally to neat and modified materials, (2) mimicked the physical changes that occur in asphalt mixes conditioned in accordance with AASHTO R 30, (3) quantified binder volatility, and (4) was extendable to long-term binder aging. The new procedure was envisioned as a replacement for the RTFOT selected as the method for short-term asphalt binder aging during the Strategic Highway Research Program on the basis of previous experience. It was hoped that the replacement method would also provide a means to measure binder volatility (mass loss) and be suitable for adaptation to replace the Pressure Aging Vessel test (PAV, AASHTO R 28) for simulating long-term aging of asphalt binders. In the research, existing short-term binder aging procedures, as well as procedures under development, were reviewed to select candidates for improvement and validation in NCHRP Project 9-36. Laboratory studies were then conducted to improve selected aspects of the can- didate procedures. Finally, a laboratory validation study was carried out to compare rheo- logical properties of neat and modified binders aged in the candidate procedures with binders aged in the RTFOT and mixtures aged in accordance with the conditioning procedure for performance testing in AASHTO R 30. The research concluded that the MGRF is an acceptable alternative to the RTFOT for both neat and modified asphalt binders. Moreover, there is a reasonable relationship between rankings of aging susceptibility measured by the RTFOT and the MGRF and that measured by AASHTO R 30. Finallyâand unexpectedlyâfor the binders tested in the research, the average aging of the neat binders was approximately the same as that for the modified binders for AASHTO R 30, RTFOT, and MGRF conditioning. The key advantage of the MGRF over the otherwise equivalent RTFOT is that the MGRF can produce aged binders in substan- tially larger quantities per run. However, the research was not successful in adapting the MGRF to provide the long-term aging of asphalt binders presently achieved with the PAV, F O R E W O R D By Edward T. Harrigan Staff Officer Transportation Research Board
and the research concluded that binder volatility is best measured using a test independent of the short-term aging procedure. The report fully documents the research leading to the proposed MGRF method and pro- vides the method in AASHTO format in an appendix. In addition, five appendixes are avail- able for download from the NCHRP Project 9-36 webpage at http://apps.trb.org/cmsfeed/ TRBNetProjectDisplay.asp?ProjectID=970: ⢠APPENDIX A: Binder Aging Bibliography ⢠APPENDIX B: Selection Study Report ⢠APPENDIX C: Volatile Collection System Study Report ⢠APPENDIX D: SAFT Optimization Study Report ⢠APPENDIX E: Verification Study Report
C O N T E N T S 1 Summary 5 Chapter 1 Introduction 5 1.1 Background 5 1.2 Objective and Scope 6 Chapter 2 Research Approach 6 2.1 Overview 6 2.2 Identify Viable Candidate Methods 10 2.3 Selection Study 11 2.4 Volatile Collection System Study 11 2.5 SAFT Optimization Study 12 2.6 Verification Study 13 2.7 Materials 15 Chapter 3 Findings 15 3.1 Introduction 15 3.2 Identify Candidate Methods 24 3.3 Selection Study 31 3.4 Volatile Collection System Study 35 3.5 SAFT Optimization Study 40 3.6 Verification Study 57 3.7 Short-Term Aging of Modified Binders 60 Chapter 4 Conclusions and Recommendations 60 4.1 Summary of Findings 62 4.2 Conclusions 62 4.3 Proposals for Future Action 64 References 66 Appendixes A through E 67 Appendix F Note: Many of the photographs, figures, and tables in this report 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.