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2018 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 RESEARCH REPORT 890 Using Recycled Asphalt Shingles with Warm Mix Asphalt Technologies Randy West Fabricio Leiva Grant Julian Adam Taylor NatioNal CeNter for asphalt teChNology Auburn, AL Elton Brown advaNCed Materials serviCes, llC Auburn, AL James Richard Willis NatioNal asphalt paveMeNt assoCiatioN Washington, D.C. Subscriber Categories Construction â¢ Design â¢ Materials â¢ Safety and Human Factors 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 National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists in highway 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 transportation departments, by committees of AASHTO, and by the Federal Highway Administration. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&Iâs recommendations are proposed to the AASHTO Board of Direc- tors and the National 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 National Academies 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 research 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 RESEARCH REPORT 890 Project 09-55 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-39066-8 Library of Congress Control Number 2018956433 Â© 2018 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 research 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. Marcia McNutt 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 National 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 CRP STAFF FOR NCHRP RESEARCH REPORT 890 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Edward Harrigan, Senior Program Officer Anthony P. Avery, Senior Program Associate Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications NCHRP PROJECT 09-55 PANEL Field of Materials and ConstructionâArea of Bituminous Materials Stacey D. Diefenderfer, Virginia Transportation Research Council, Charlottesville, VA (Chair) Kim A. Willoughby, Washington State DOT, Olympia, WA Michael S. Buchanan, Oldcastle Materials Company, Birmingham, AL Peter C. Capon, Rieth-Riley Construction, Inc., Goshen, IN German Claros, HVJ Associates, Corpus Christi, TX Greg Hainsworth, Delaware DOT, Dover, DE Baoshan Huang, University of Tennessee, Knoxville, TN Joseph W. Schroer, N.B. West Contracting, Sullivan, MO James M. Winford, Jr., Prairie Contractors, Inc., Opelousas, LA Matthew Corrigan, FHWA Liaison Audrey Copeland, Industry Liaison
F O R E W O R D This report presents commentary on recent revisions to AASHTO Provisional Standard PP 78-17: Design Considerations When Using Reclaimed Asphalt Shingles (RAS) in Asphalt Mixtures. The report will be of immediate interest to materials engineers in state highway agencies and in the construction industries with responsibility for design and evaluation of asphalt mixtures. The use of recycled asphalt shingles (RAS) in asphalt mixtures has increased dramati- cally in the last decade as many states have allowed the use of RAS in their asphalt paving mixtures. This increased use is largely a result of the need to recycle and conserve natu- ral resources. The concurrent introduction of warm mix asphalt (WMA) technologies has provided additional opportunities to reduce energy consumption and emissions in asphalt pavement construction. RAS binders have very high softening points, so their use in asphalt mixtures incorporat- ing WMA technologies could possibly result in incomplete blending of the RAS and virgin asphalt binders. Volumetric and engineering properties and performance data need to be obtained for WMAâRAS mixtures in order to update AASHTO PP 78-17 to provide guidance on RAS use with WMA technologies. The objective of this research was to develop a design and evaluation procedure that provides acceptable performance of asphalt mixtures incorporating WMA technologies and RASâwith and without recycled asphalt pavement (RAP)âfor project-specific ser- vice conditions. The research addressed (1) minimizing the risk of designing and producing mixes containing WMA technologies and RAS with poor constructability, durability, or susceptibility to premature cracking; (2) evaluating type, source, quality, and characteristics of RAS; (3) binder design and selection, including evaluation of the composite WMAâRAS binder; and (4) the typical range of WMA production temperatures. The research was per- formed by the National Center for Asphalt Technology, Auburn, Alabama, with the support of Advanced Materials Services, LLC, also of Auburn, Alabama. The research encompassed an extensive engineering evaluation of WMA and hot-mix asphalt (HMA) mixtures containing RAS from eight field projects and a comparison of these results with the short-term field performance of the WMA and control HMA pave- ments. Performance-related laboratory tests were conducted to evaluate the performance grade of the recovered binders, mixture stiffness over a wide temperature range, moisture susceptibility, fatigue cracking, thermal cracking, and permanent deformation. Statistical analysis of the research results found no detrimental effect of using WMA technologies in mixtures containing RAS. As might be expected, laboratory testing found that using WMA technologies improves the cracking resistance of some RAS mixtures. In By Edward Harrigan Staff Officer Transportation Research Board
practical terms, no difference was found between the field performance of the WMA mix- tures containing RAS with that of the control HMA mixtures. The practical outcome of the project is a set of proposed revisions to AASHTO PP 78-17 that expands its application to WMAâRAS mixtures. The research also produced a set of proposed best practices for the processing of recycled asphalt shingles. This report fully documents the research and includes four appendices presenting (1) contractor mixture designs and quality control data for the field projects included in the research; (2) results of differential scanning calorimetry to measure the activation energy of RAS binders and scanning electron microscopy to indicate dispersion of RAS in asphalt mixtures; (3) an experimental evaluation of the activation of RAS binder in asphalt con- crete; and (4) the best practices document.
C O N T E N T S 1 Chapter 1 Background 1 Introduction 2 Project Objectives and Scope 3 Report Organization 3 Literature Review 3 Composition of Asphalt Shingles 5 Mix Design 5 Laboratory Testing of Asphalt Mixtures Containing RAS 8 Warm Mix Asphalt 9 Asphalt Mixtures Using RAS and a WMA Technology 11 Summary of Performance of RAS Mixture Experimental Sections 12 Examples of Projects That Used RAS and WMA 14 Chapter 2 Experimental Plan 14 Introduction 14 Production and Construction Information 15 Performance Monitoring 15 Field Performance Data Collection 16 Laboratory Testing of Field Mixes from New Projects 16 Materials and Mixture Properties 28 Summary of Laboratory Performance Testing 28 Mix Design Verifications 29 Additional Testing and Analysis of Mixtures Containing RAS 30 Chapter 3 Production, Construction, and Performance of Field Projects 30 Existing Projects 30 Austin, Texas 35 Aurora, Illinois 42 Fort Worth, Texas 48 New Projects 48 Larsen, Wisconsin 56 Enterprise, Alabama 66 Oak Ridge, Tennessee 72 Wilson, North Carolina 80 La Porte, Indiana 86 Production and Construction Summary of New Projects 86 Field Performance Summary of Existing and New Projects 86 Properties of HMA and WMA Mixtures of New Projects 86 Asphalt Content 89 Binder Grade 91 Deleterious Materials and Fiber 91 Dynamic Modulus (E*) 93 Hamburg Wheel-Tracking Test 93 Flow Number 97 Bending Beam Fatigue
97 Energy Ratio 98 Indirect Tension Creep Compliance and Strength 98 Overlay Test 98 Fracture Energy and Flexibility Index 100 Semi-Circular BendâLTRC Test 101 Cracking Susceptibility of Cores Obtained from Field Inspections 103 Chapter 4 Analysis of Engineering Properties 103 Binder Properties 103 Mixture Properties 103 Volumetric Mix Properties 103 Mixture Engineering Properties 103 Dynamic Modulus 108 Hamburg Wheel-Tracking Test 108 Flow Number 109 Bending Beam Fatigue 110 Overlay Test 110 Flexibility Index 112 Statistical Analyses of Other Tests 112 Summary of Laboratory Performance Test Results 113 Correlation Analysis Among Mixture Properties 115 DTc Analysis 115 Identification of Common Effects Among Test Results 116 Effect of Material Properties on Laboratory Performance 117 Dynamic Modulus Master Curve Parameters as Indicators of Cracking Susceptibility 121 Low-Temperature Cracking 124 Chapter 5 Mix Design Verifications 124 Larsen, Wisconsin 124 Enterprise, Alabama 127 Oak Ridge, Tennessee 130 Wilson, North Carolina 130 La Porte, Indiana 132 Property Comparisons 137 Summary 138 Chapter 6 Economic Analysis of Asphalt Mixtures Containing RAS 141 Chapter 7 Findings 141 Production and Construction of RAS Mixtures 141 Short-Term Field Performance of RAS Mixtures 142 Engineering Properties of RAS Mixtures 142 Mix Design Verifications of RAS Mixtures 143 Economic Analysis of Asphalt Mixtures Containing RAS 143 Other Studies 143 General Conclusion and Proposed Implementation Actions 145 Bibliography 148 Appendix A Contractor Mixture Designs and Quality Control Data 163 Appendix B Activation Energy for Recycled Asphalt Shingle Binders and Dispersion of RAS in Asphalt Mixtures 174 Appendix C Evaluating the Activation of Asphalt Binder from Recycled Asphalt Shingles in Asphalt Concrete 191 Appendix D Best Practices for Processing Recycled Asphalt Shingles