HIGHWAY TECHNET   VIRTUAL EXPO   PAVEMENTS INDEX
Asphalt Mix Technology
Two Parts Technology, One Part Innovation, Mix Well
DP-90 Mobile Asphalt Laboratories
TE-18 Stone-Matrix Asphalt
TE-39 SHRP Asphalt Support Projects
      Pooled Fund Equipment Study Support (SHRP)
      SHRP Field Implementation Asphalt
National Asphalt Training Center II
Asphalt is the predominant material used for paving in the United States, and more than 500 million tons of asphalt are placed on America's highways annually. Since the 1820s, selecting, designing, producing, specifying, and placing asphalt material has been the subject of research and analysis, leading all the way to today's Strategic Highway Research Program (SHRP) and specialty applications such as Stone-Matrix asphalt (SMA).

Currently, an array of asphalt mixes exists, from dense graded to large stone and from open graded to stone-matrix asphalt. However, as Francis Hveem, an early leader in asphalt mix design, cautioned more than 80 years ago, regardless of arrays and names, "...the materials...will all continue to act and respond to the same natural laws." Research to understand these laws, both on the road and in the laboratory, has intensified over the last several decades as the volume, type, axle load, and tire pressure of today's traffic continuously increases. other imporatnt factors also come into play: (1) crude supplies are less consistent, (2) quality stone is more expensive and less available, (3) recycling old pavements demands a better understanding of the natural laws, and (4) the service-life expectancy of pavements needs to increase in order to reduce construction delays.

The asphalt mix technology group evaluates and promotes design, control, and testing techniques to improve asphalt mixes. The SHRP SUPERPAVE incorporates a full system approach to mix design and analysis, including a performance-based binder specification and tests, a design technique that uses consensus standards, testing techniques to perform design mixes, and also an innovative technique to evaluate and predict performance in the laboratory.

While SUPERPAVE provides for a full approach to mix designs, the search for asphalt mix innovation continues with the evaluation of the American version of European stone-matrix asphalt and search for a performance tester. These projects demonstrate a decade-long commitment to evaluating and adopting better technology.

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U.S. Department of Transportation
Federal Highway Administration