Reclaimed Asphalt Pavement (RAP) in Asphalt Mixtures: State-of

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  • Research, Development, and TechnologyTurner-Fairbank Highway Research Center6300 Georgetown PikeMcLean, VA 22101-2296

    Reclaimed Asphalt Pavement in AsphaltMixtures: State of the Practice

    PublicAtion no. FHWA-HRt-11-021 APRil 2011

  • FOREWORD

    Recycling asphalt pavement creates a cycle of reusing materials that optimizes the use of natural resources. Reclaimed asphalt pavement (RAP) is a useful alternative to virgin materials because it reduces the need to use virgin aggregate, which is a scarce commodity in some areas of the United States. It also reduces the amount of costly new asphalt binder required in the production of asphalt paving mixtures. This report informs practitioners about the state of the practice for RAP use in the United States as well as best practices for increasing the use of RAP in asphalt pavement mixtures while maintaining high-quality pavement infrastructures. High percentage RAP mixtures are achieved with processing and production practices, resulting in cost and energy savings. Based on an evaluation of pavements containing 30 percent RAP through the Long-Term Pavement Performance (LTPP) program, it has been determined that the performance of pavements containing up to 30 percent RAP is similar to that of pavements constructed from virgin materials with no RAP. This report is of interest to engineers, contractors, and others involved in the specification and design of asphalt mixtures for flexible pavements, as well as those involved in promoting the optimal use of RAP.

    Peter Stephanos Jorge E. Pagn-Ortiz Director, Office of Pavement Technology Director, Office of Infrastructure Research and Development

    Notice This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers names appear in this report because they are considered essential to the objective of the document.

    Quality Assurance Statement The Federal Highway Administration (FHWA) provides high-quality information to serve the Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

  • TECHNICAL REPORT DOCUMENTATION PAGE

    Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

    1. Report No. FHWA-HRT-11-021

    2. Government Accession No.

    3. Recipients Catalog No.

    4. Title and Subtitle Reclaimed Asphalt Pavement in Asphalt Mixtures: State of the Practice

    5. Report Date April 2011 6. Performing Organization Code

    7. Author(s) Audrey Copeland

    8. Performing Organization Report No.

    9. Performing Organization Name and Address Office of Infrastructure Research and Development Federal Highway Administration 6300 Georgetown Pike McLean, VA 22101

    10. Work Unit No. (TRAIS) 11. Contract or Grant No.

    12. Sponsoring Agency Name and Address Turner-Fairbank Highway Research Center Federal Highway Administration 6300 Georgetown Pike McLean, VA 22101-2296

    13. Type of Report and Period Covered

    14. Sponsoring Agency Code

    15. Supplementary Notes The Contracting Officers Technical Representative (COTR) was Audrey Copeland, HRDI-10. 16. Abstract With increased demand and limited aggregate and binder supply, hot mix asphalt (HMA) producers discovered that reclaimed asphalt pavement (RAP) is a valuable component in HMA. As a result, there has been renewed interest in increasing the amount of RAP used in HMA. While a number of factors drive the use of RAP in asphalt pavements, the two primary factors are economic savings and environmental benefits. RAP is a useful alternative to virgin materials because it reduces the use of virgin aggregate and the amount of virgin asphalt binder required in the production of HMA. Using RAP greatly reduces the amount of construction debris going into landfills, and it does not deplete nonrenewable natural resources such as virgin aggregate and asphalt binder. Ultimately, recycling asphalt creates a cycle of reuse that optimizes the use of natural resources and sustains the asphalt pavement industry.

    More widespread use of higher amounts of RAP in asphalt mixtures requires support from State transportation departments and the HMA industry. State transportation departments have expressed concern over the lack of guidance on the use of high percentages of RAP (high RAP) mixtures, as well as the lack of information on their performance. As a result, there is a need for national guidance on best practices when using RAP and documented information about long-term performance of high RAP pavements.

    The intent of this report is to provide state-of-the-practice information on including higher amounts of RAP in asphalt mixtures. The state of the practice for RAP use across the United States, as well as common challenges for increasing the use of RAP, are identified. Best practices applicable for the use of RAP are presented to identify general parameters that must be considered when developing specifications and to provide information on available resources and best practices for sourcing, processing, stockpiling, testing, designing, evaluating, producing, and placing high RAP mixtures, as well as practices to attain the best performance for high RAP mixtures . 17. Key Words Reclaimed asphalt pavement (RAP), Recycled asphalt, Hot mix asphalt (HMA), Asphalt mixtures, Superpave, Performance

    18. Distribution Statement No restrictions.

    19. Security Classif. (of this report) Unclassified

    20. Security Classif. (of this page) Unclassified

    21. No. of Pages 55

    22. Price

  • ii

    SI* (MODERN METRIC) CONVERSION FACTORS APPROXIMATE CONVERSIONS TO SI UNITS

    Symbol When You Know Multiply By To Find Symbol LENGTH

    in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km

    AREA in2 square inches 645.2 square millimeters mm2

    ft2 square feet 0.093 square meters m2

    yd2 square yard 0.836 square meters m2

    ac acres 0.405 hectares ha mi2 square miles 2.59 square kilometers km2

    VOLUME fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft3 cubic feet 0.028 cubic meters m3

    yd3 cubic yards 0.765 cubic meters m3

    NOTE: volumes greater than 1000 L shall be shown in m3

    MASS oz ounces 28.35 grams glb pounds 0.454 kilograms kgT short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t")

    TEMPERATURE (exact degrees) oF Fahrenheit 5 (F-32)/9 Celsius oC

    or (F-32)/1.8 ILLUMINATION

    fc foot-candles 10.76 lux lx fl foot-Lamberts 3.426 candela/m2 cd/m2

    FORCE and PRESSURE or STRESS lbf poundforce 4.45 newtons N lbf/in2 poundforce per square inch 6.89 kilopascals kPa

    APPROXIMATE CONVERSIONS FROM SI UNITS Symbol When You Know Multiply By To Find Symbol

    LENGTHmm millimeters 0.039 inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers 0.621 miles mi

    AREA mm2 square millimeters 0.0016 square inches in2

    m2 square meters 10.764 square feet ft2

    m2 square meters 1.195 square yards yd2

    ha hectares 2.47 acres ac km2 square kilometers 0.386 square miles mi2

    VOLUME mL milliliters 0.034 fluid ounces fl oz L liters 0.264 gallons gal m3 cubic meters 35.314 cubic feet ft3

    m3 cubic meters 1.307 cubic yards yd3

    MASS g grams 0.035 ounces ozkg kilograms 2.202 pounds lbMg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T

    TEMPERATURE (exact degrees) oC Celsius 1.8C+32 Fahrenheit oF

    ILLUMINATION lx lux 0.0929 foot-candles fc cd/m2 candela/m2 0.2919 foot-Lamberts fl

    FORCE and PRESSURE or STRESS N newtons 0.225 poundforce lbf kPa kilopascals 0.145 poundforce per square inch lbf/in2

    *SI is the symbol for th International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. e(Revised March 2003)

  • iii

    TABLE OF CONTENTS

    CHAPTER 1. INTRODUCTION ................................................................................................ 1 BACKGROUND ..................................................................................................................... 2 HISTORICAL PERSPECTIVE ............................................................................................ 3 PURPOSE AND METHODOLOGY .................................................................................... 4

    CHAPTER 2. STATE OF THE PRACTICE FOR RAP USE.................................................. 7 SURVEY OF RAP SPECIFICATIONS AND USE IN THE UNITED STATES ............. 8

    Updated Survey Results and Progress .............................................................................. 10 CHALLENGES FOR INCREASING THE USE OF RAP ............................................... 13 ADDITIONAL SURVEY RESULTS .................................................................................. 15

    RAP Fractionation ............................................................................................................ 16 Determining AC of RAP ................................................................................................... 16 Mix Design Methods for RAP Mixes ............................................................................... 1