NCHRP Research Report 1130	National Cooperative Highway Research Program

Capturing the Durability of High Recycled
Binder Ratio Asphalt Mixtures

TRANSPORTATION RESEARCH BOARD 2024 EXECUTIVE COMMITTEE*

OFFICERS

CHAIR: Carol A. Lewis, Professor, Transportation Studies, Texas Southern University, Houston

VICE CHAIR: Leslie S. Richards, General Manager, Southeastern Pennsylvania Transportation Authority (SEPTA), Philadelphia

EXECUTIVE DIRECTOR: Victoria Sheehan, Transportation Research Board, Washington, DC

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James F. Albaugh, President and CEO, The Boeing Company (retired), Scottsdale, AZ

Carlos M. Braceras, Executive Director, Utah Department of Transportation, Salt Lake City

Douglas C. Ceva, Vice President, Customer Lead Solutions, Prologis, Inc., Jupiter, FL

Nancy Daubenberger, Commissioner of Transportation, Minnesota Department of Transportation, St. Paul

Marie Therese Dominguez, Commissioner, New York State Department of Transportation, Albany

Garrett Eucalitto, Commissioner, Connecticut Department of Transportation, Newington

Chris T. Hendrickson, Hamerschlag University Professor of Engineering Emeritus, Carnegie Mellon University, Pittsburgh, PA

Randell Iwasaki, President and CEO, Iwasaki Consulting Services, Walnut Creek, CA

Ashby Johnson, Executive Director, Capital Area Metropolitan Planning Organization (CAMPO), Austin, TX

Joel M. Jundt, Secretary of Transportation, South Dakota Department of Transportation, Pierre

Hani S. Mahmassani, W.A. Patterson Distinguished Chair in Transportation; Director, Transportation Center, Northwestern University, Evanston, IL

Scott C. Marler, Director, Iowa Department of Transportation, Ames

Ricardo Martinez, Adjunct Professor of Emergency Medicine, Emory University School of Medicine, Decatur, GA

Michael R. McClellan, Vice President, Strategic Planning, Norfolk Southern Corporation, Atlanta, GA

Russell McMurry, Commissioner, Georgia Department of Transportation, Atlanta

Craig E. Philip, Research Professor and Director, VECTOR, Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN

Steward T.A. Pickett, Distinguished Senior Scientist, Cary Institute of Ecosystem Studies, Millbrook, NY

Susan A. Shaheen, Professor and Co-director, Transportation Sustainability Research Center, University of California, Berkeley

Marc Williams, Executive Director, Texas Department of Transportation, Austin

EX OFFICIO MEMBERS

Michael R. Berube, Deputy Assistant Secretary for Sustainable Transportation, U.S. Department of Energy, Washington, DC

Amit Bose, Administrator, Federal Railroad Administration, Washington, DC

Tristan Brown, Deputy Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. Department of Transportation, Washington, DC

Steven Cliff, Executive Officer, California Air Resources Board, Sacramento

Rand Ghayad, Senior Vice President, Association of American Railroads, Washington, DC

LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Germantown, MD

Robert C. Hampshire, Deputy Assistant Secretary for Research and Technology, U.S. Department of Transportation, Washington, DC

Jason Kelly, Deputy Commanding General for Civil Works and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC

Zahra “Niloo” Parvinashtiani, Engineer, Mobility Consultant Solutions, Iteris Inc., Fairfax, VA, and Chair, TRB Young Members Coordinating Council

Ann Phillips (Rear Admiral, U.S. Navy, retired), Maritime Administrator, Maritime Administration, U.S. Department of Transportation, Washington, DC

Sophie Shulman, Deputy Administrator, National Highway Traffic Safety Administration, Washington, DC

Karl Simon, Director, Transportation and Climate Division, U.S. Environmental Protection Agency, Washington, DC

Paul P. Skoutelas, President and CEO, American Public Transportation Association, Washington, DC

Polly Trottenberg, Deputy Secretary of Transportation, U.S. Department of Transportation, Washington, DC

Jim Tymon, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC

Veronica Vanterpool, Acting Administrator, Federal Transit Administration, Washington, DC

Michael Whitaker, Administrator, Federal Aviation Administration, U.S. Department of Transportation, Washington, DC

Kristin White, Acting Administrator, Federal Highway Administration, U.S. Department of Transportation, Washington, DC

Vinn White, Deputy Administrator, Federal Motor Carrier Safety Administration, Washington, DC

___________________

^* Membership as of November 2024.

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM

Capturing the Durability of High Recycled
Binder Ratio Asphalt Mixtures

Amy Epps Martin
Edith Arámbula Mercado
Juliana Montañez Gil
TEXAS A&M TRANSPORTATION INSTITUTE
College Station, TX

Yong-Rak Kim
Santosh Reddy Kommidi
TEXAS A&M UNIVERSITY
College Station, TX

Nam Tran
Fan Yin
Raquel Moraes
Carolina Rodezno
Madhav Verma
Biswajit Kumar Bairgi
NATIONAL CENTER FOR ASPHALT TECHNOLOGY AT AUBURN UNIVERSITY
Auburn, AL

Gayle King
College Station, TX

Subscriber Categories
Construction • Materials • Pavements

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, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest 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 initiated an objective national highway research program using modern scientific techniques—the 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 (FHWA), United States Department of Transportation, under Agreement No. 693JJ31950003.

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 TRB’s recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive committee 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, universities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists 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 FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&I’s recommendations are proposed to the AASHTO Board of Directors 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.

NCHRP RESEARCH REPORT 1130

Project 09-65
ISSN 2572-3766 (Print)
ISSN 2572-3774 (Online)
ISBN 978-0-309-72759-4
Library of Congress Control Number 2024950222
Digital Object Identifier: https://doi.org/10.17226/27991

© 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the 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, APTA, FAA, FHWA, FTA, GHSA, or NHTSA 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; the FHWA; or the program sponsors.

The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.

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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM

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Learn more about the Transportation Research Board at www.TRB.org.

COOPERATIVE RESEARCH PROGRAMS

CRP STAFF FOR NCHRP RESEARCH REPORT 1130

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program

Roberto Barcena, Senior Program Officer

Anthony P. Avery, Senior Program Assistant

Natalie Barnes, Director of Publications

Heather DiAngelis, Associate Director of Publications

NCHRP PROJECT 09-65 PANEL
Field of Materials and Construction—Area of Bituminous Materials

Ervin L. Dukatz, Jr., Flyereld Consulting, LLC, La Crosse, WI (Chair)

Eliana V. Carlson, Connecticut Department of Transportation, Rocky Hill, CT

Erik Lyngdal, Wisconsin Department of Transportation, Madison, WI

Tanya M. Nash, Asphalt Testing Solutions and Engineering, Jacksonville, FL

Geoffrey Michael Rowe, Abatech, Inc., Blooming Glen, PA

Aaron Schwartz, Vermont Agency of Transportation, Barre, VT

Andrew David Wargo, North Carolina Department of Transportation, Raleigh, NC

David J. Mensching, FHWA Liaison

AUTHOR ACKNOWLEDGMENTS

The research reported herein was performed under NCHRP Project 09-65, “Capturing Durability of High Recycled Binder Ratio (RBR) Asphalt Mixtures,” by the Texas A&M Transportation Institute (TTI), Texas A&M University (TAMU), the National Center for Asphalt Technology (NCAT) at Auburn University, and Gayle King, Consultant. The Texas A&M Sponsored Research Services served as the fiscal administrator. Amy Epps Martin, Florence Wiley Professor II of Civil & Environmental Engineering at TAMU, was the Principal Investigator and Nam Tran, Associate Director and Research Professor at Auburn University, was the Co-principal Investigator. Other authors of this report are Edith Arámbula Mercado, Yong-Rak Kim, Juliana Montañez Gil, Santosh Reddy Kommidi, Fan Yin, Raquel Moraes, Carolina Rodezno, Madhav Verma, and Biswajit Kumar Bairgi. Thanks are also due to Tony Barbosa, Austin Hinrichs, Michael Hoagland, Peyton Hofferichter, Kathryn Jaeckle, Caitlyn Jennings, Tyler Powell, and Ramon Rodriguez at TTI for their work in laboratory testing and to Adam Taylor, Tina Taylor, and Pamela Turner at NCAT for their work in materials sampling and laboratory testing.

The mix designs and materials donations required for the success of this project were realized based on the cooperation of departments of transportation from four states and multiple contractors and materials suppliers. Their participation is also recognized and greatly appreciated.

FOREWORD

By Roberto Barcena
Staff Officer
Transportation Research Board

NCHRP Research Report 1130: Capturing the Durability of High Recycled Binder Ratio Asphalt Mixtures presents a stepwise approach and strategies to develop durable asphalt mixtures with high recycled binder ratio (RBR). The stepwise process and strategies were derived from extensive laboratory experiments involving several virgin binders and aggregates, recycled asphalt materials, and additives. The laboratory work was complemented with performance modeling to assess the resistance to fatigue loading after aging and moisture conditioning.

This report will be of immediate interest to pavement materials personnel at transportation agencies who seek to increase the use of recycled asphalt materials in mixtures with enhanced cracking resistance, balanced rutting performance, and sufficient moisture and raveling resistance.

Environmental sustainability and economic benefits motivate the maximum use of recycled asphalt materials (RAM), including reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS), in asphalt mixtures. However, adequate durability must be maintained when these typically stiff, brittle, and aged materials are added to virgin asphalt-aggregate mixtures. To maximize durability, state departments of transportation currently limit the RAP and RAS contents and their overall RBR. Strategies for improving binder rheology and mixture durability include utilizing a softer base binder or adding a recycling agent (RA) (e.g., a rejuvenator); however, it is difficult to determine the durability of mixtures using these strategies. In addition, these types of high RAM content asphalt mixtures are difficult for agencies to accept because no uniform AASHTO practice for their assessment is available.

Under NCHRP Project 09-65, “Capturing Durability of High Recycled Binder Ratio (RBR) Asphalt Mixtures,” the Texas A&M Transportation Institute was asked to (1) propose draft language for AASHTO consideration for standard practice and associated test methods for the design and evaluation of durable high RAM content asphalt mixtures and (2) develop revised draft language for AASHTO consideration for the standard practice for Characterization of Asphalt Mixtures with High Recycled Materials Contents and Recycling Agents to address mixture durability.

In addition to the report published as NCHRP Research Report 1130, the following deliverables can be found on the National Academies Press webpage for NCHRP Research Report 1130: Capturing the Durability of High Recycled Binder Ratio Asphalt Mixtures (https://doi.org/10.17226/27991) under “Resources at a Glance”:

1. Appendix A – Phase I Literature Review
2. Appendix B – Questionnaires
3. Appendix C – Draft AASHTO Standard Practice

The original content of the following deliverable was sent to the AASHTO Committee on Materials and Pavements for evaluation:

1. Appendix D – Proposed Implementation Guide for Draft Standard Practice

CONTENTS

Summary

Chapter 1 Introduction

1.1 Objective

1.2 Approach and Scope

Chapter 2 Experiments

2.1 Component Materials and Characterization

2.2 Proportions (Mix Design Verification, Additive Doses, and RBA)

2.3 Mixture Performance Evaluation

2.4 Mixture Cracking Performance Modeling

2.5 Evaluation Tools

Chapter 3 Durability Evaluation

3.1 Component Materials and Proportions

3.2 North Moisture-Resistant Mixtures

3.3 South Moisture-Resistant Mixtures

3.4 North Moisture-Susceptible Mixtures

3.5 South Moisture-Susceptible Mixtures

Chapter 4 Mixture Comparisons

4.1 Mixture Comparison of Laboratory Performance Characterization

4.2 Mixture Comparison of Cracking Performance Modeling

4.3 Component Materials Screening

Chapter 5 Cost Analysis

5.1 Cost Analysis Considerations

5.2 Cost Analysis Results

Chapter 6 Summary and Path Forward

6.1 Summary

6.2 Path Forward

References

Appendices