Asphalt Rubber Technology Information Center
Existing and Evolving Methods of Materials Evaluation for Waste-Modified Asphalt Mixtures
Terrel, Ronald L.; Lundy, James R. and Hicks, Gary R.  
October, 1993  
Key Words:
waste materials, asphalt concrete, SHRP, mixture characteristics, performance, rubber-modified asphalt mixtures  
A continued increase in the use of waste materials in highway construction appears inevitable.  The incorporation of
waste and/or by-products in asphalt concrete mixtures has resulted in many successes and some costly failures.  
Traditional asphalt mixture design and evaluation test procedures are generally ineffective in identifying which modified
mixtures will perform well and which will fail.  The shortcomings of traditional methodologies are due to the empirically
based design methods and interpretation of results.  However, for waste-modified mixture designs and performance
predictions will necessarily often fail.
Mixture evaluation and testing procedures and performance based criteria, developed as part of the Strategic Highway
Research Program (SHRP), may be better suited to distinguish between good and bad performing mixtures.  These tests
attempt to identify the fundamental material properties of the mixture.  Nevertheless, these new procedures have not
been fully demonstrated on waste-modified asphalt mixtures.  Furthermore, field performance of waste-modified
mixtures characterized using SHRP methodology has not been studied.  To facilitate the implementation of these
evolving procedures, a SHRP-based test methodology that assists in selection of waste-modified mixtures is described.
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