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TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2008 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 598 Subject Areas Pavement Design, Management, and Performance ⢠Materials and Construction Performance-Related Tests of Recycled Aggregates for Use in Unbound Pavement Layers Athar Saeed APPLIED RESEARCH ASSOCIATES, INC. Vicksburg, MS 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 598 Project 4-31 ISSN 0077-5614 ISBN: 978-0-309-099202 Library of Congress Control Number 2008900695 © 2008 Transportation Research Board COPYRIGHT PERMISSION 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. Such approval reflects the Governing Boardâs judgment that the program concerned is of national importance and appropriate with respect to both the purposes and resources of the National Research Council. The members of the technical committee selected to monitor this project and to review this report were chosen for recognized scholarly competence and with due consideration for the balance of disciplines appropriate to the project. The opinions and conclusions expressed or implied are those of the research agency that performed the research, and, while they have been accepted as appropriate by the technical committee, they are not necessarily those of the Transportation Research Board, the National Research Council, the American Association of State Highway and Transportation Officials, or the Federal Highway Administration, U.S. Department of Transportation. Each report is reviewed and accepted for publication by the technical committee according to procedures established and monitored by the Transportation Research Board Executive Committee and the Governing Board of the National Research Council. The Transportation Research Board of the National Academies, the National Research Council, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, and the individual states participating in 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 this report.
CRP STAFF FOR NCHRP REPORT 598 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Amir N. Hanna, Senior Program Officer Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor NCHRP PROJECT 4-31 Field of Materials and ConstructionâArea of General Materials Larry Lockett, Alabama DOT, Montgomery, AL (Chair) Donald Dwyer, New York State DOT, Albany, NY Ãna Connolly, National Asphalt Pavement Association, Lanham, MD John B. Metcalf, Louisiana State University (retired), Baton Rouge, LA William Sheftick, Bowser-Morner, Inc., Springfield, IL Mark B. Snyder, Bridgeville, PA Jeff S. Uhlmeyer, Washington State DOT, Olympia, WA John âJackâ Youtcheff, FHWA Liaison G. P. Jayaprakash, TRB Liaison AUTHOR ACKNOWLEDGMENTS The research under NCHRP Project 4-31, âTests of Recycled Aggregates for Use in Unbound Pavement Layers,â reported herein was performed by Applied Research Associates (ARA), Inc. Dr. Athar Saeed was the principal investigator. Messrs. Harold Von Quintus, Jagannath Mallela, and Prithivi Kandhal assisted with the literature search and telephone interviews. Drs. Jim W. Hall, Jr., Michael I. Hammons, and Walter Barker helped develop the work plan. Messrs. Prithivi Kandhal, Leet Denton, and Rick Sniegowski served as consultants for all project tasks. Laboratory tests were conducted by Boudreau Engineering, Inc., under the supervision of Mr. Richard L. Boudreau. Several state departments of transportation and their contractors provided recycled material for lab- oratory testing; their contribution to this research effort is acknowledged. 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 contains recommendations for performance-related procedures to test and select recycled hot-mix asphalt (HMA) and portland cement concrete (PCC) materials for use in unbound layers of highway pavements. The report provides a comprehensive descrip- tion of research intended to help materials engineers evaluate and select the reclaimed asphalt pavement (RAP) and reclaimed concrete pavement (RCP) materials that should contribute to good performing pavements. Also, the report describes procedures for the recommended tests. The contents of this report will be of immediate interest to materials engineers, researchers, and others concerned with the construction and performance of asphalt and PCC pavements. The use of RAP and RCP and materials reclaimed from structures in unbound pavement layers should provide technical, economic, and other benefits. Although a great deal of research has been performed on the properties of aggregates used in pavement construc- tion, limited research has addressed the use of recycled aggregates in unbound pavement layers. For example, research performed under NCHRP Project 4-23, and reported in NCHRP Report 453, âPerformance-Related Tests of Aggregates for Use in Unbound Pave- ment Layers,â evaluated aggregate tests and identified a set of aggregate tests that relate to performance of unbound pavement layers. However, the project dealt only with virgin aggregates; it did not consider the use of recycled materials. Because RAP and RCP materi- als are reclaimed from highway pavements, they contain binders and contaminants that are not found in virgin aggregates. This difference in material constituents, the long exposure of RAP and RCP materials to the elements, and constructability concerns raise questions about the validity of the tests intended for evaluating virgin aggregates for use in evaluating RAP and RCP materials. Under NCHRP Project 4-31, âTests of Recycled Aggregates for Use in Unbound Pave- ment Layers,â Applied Research Associates, Inc. was assigned the task of recommending procedures for performance-related testing and selection of recycled HMA and PCC mate- rials for use in unbound pavement layers. To accomplish this objective, the researchers reviewed relevant domestic and foreign literature; identified aggregate properties that influ- ence the performance of pavements; identified and evaluated, in a laboratory investigation, the aggregate tests currently used in the United States and other countries as well as poten- tial new aggregate tests to measure performance-related properties; and recommended a set of performance-related tests for evaluating recycled aggregates. The report documents the work performed under NCHRP Project 4-31 and discusses the linkage between the recom- mended tests and the performance of asphalt and concrete pavements. F O R E W O R D By Amir N. Hanna Staff Officer Transportation Research Board
The recommended set of aggregate tests can be used to evaluate and select RAP and RCP materials for use in the unbound layers of asphalt and PCC pavements. The report includes descriptions of those recommended test methods that are not currently being used in the United States. These test methods will be particularly useful to highway agencies and, there- fore, may be considered for adoption by AASHTO as standard test methods. Appendixes A through C contained in the research agencyâs final report are not published herein. These appendixes are available on the TRB website as NCHRP Web-Only Docu- ment 119. These appendixes discuss the following: Appendix A: Literature Review and Background Information Appendix B: Recommended New Aggregate Tests Appendix C: Surface Dielectric Measurements
C O N T E N T S 1 Summary 2 Chapter 1 Background and Research Approach 2 Project Background 2 Research Objective 2 Scope of Study 3 Research Approach 3 Report Organization 4 Chapter 2 Pavement Performance and Recycled Aggregate Properties 4 Background 4 Flexible Pavements 4 Rigid Pavements 4 RAP and RCP Properties 5 Mass Properties 8 Particle Properties 9 In-Service Factors Affecting RAP and RCP Performance 9 Moisture Conditions 10 State of Stress 10 Construction Method 10 Freeze-Thaw 10 Loading Rate 11 Chapter 3 Selection of Candidate Test Methods and Materials 11 Selection and Description of Test Methods 11 Screening Tests 11 Shear Strength Tests 13 Stiffness and Permeability Tests 14 Frost Susceptibility 14 Durability 14 Toughness and Abrasion Resistance 14 Selection and Description of Candidate Recycled Materials 14 RCP with Limestone 15 RCP with Gravel 16 RCP with Granite 16 RAP with Limestone 17 RAP with Granite 17 RAP with Gravel 20 Chapter 4 Laboratory Test Program and Test Results 20 Laboratory Investigation 20 Results of Laboratory Tests
20 Grain Size Analysis 20 Moisture/Density Relations 20 Static Triaxial Test 20 Repeated Load Triaxial Test Results 26 Resilient Modulus Test Results 28 Toughness and Abrasion Resistance 28 Durability 33 Frost Susceptibility 35 Chapter 5 Analysis of Test Data 35 Selection of Performance-Based Test Methods 35 Toughness and Abrasion Resistance 35 Durability 35 Frost Susceptibility 35 Static Triaxial Test 36 Repeated Load Triaxial Test 40 Resilient Modulus Test 45 Test Method Selection Summary 46 Selection of Recycled Materials for Intended Use 47 Selection Based on Toughness Test 48 Selection Based on Frost Susceptibility Test 48 Selection Based on Static Triaxial Test 48 Selection Based on Repeated Load Triaxial Test 48 Selection Based on Material Stiffness 51 Chapter 6 Conclusions and Suggested Research 51 Conclusions 51 Suggested Research 51 Accelerated Pavement Testing 52 In-Service Test Pavements 53 References