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Warm Mix Asphalt


What is Warm Mix Asphalt?

Warm Mix Asphalt (WMA) is the generic term for any technology (additive or water foaming technique) added to an asphalt mixture that allows the mixing and compaction temperature to be reduced by 20 to 100°F. It allows the mix to remain workable at lower temperatures, and has potential environmental, operational, and performance benefits over traditional hot mix asphalt (HMA).


Benefits of Warm Mix Asphalt Warm Mix Asphalt

Several benefits have been found when using Warm Mix Asphalt:

  • Environmental
    • Lower greenhouse gas emissions
    • Lower fuel consumption
    • Reduced exposure of workers to fumes
    • Eliminates the need for fume evacuation equipment on plant and paver


  • Operational
    • Lower plant wear
    • Longer haul distances
    • Late season paving
    • Better compaction
    • Early site opening
    • More comfortable working conditions for plant and paving crews


  • Performance
    • Reduced binder aging
    • More time for mixture compaction
    • Cold weather paving
    • Can use RAP with WMA
    • Less susceptible to low temperature and fatigue cracking
    • Eliminates bump at joint when overlaying concrete


WMA Reference Documents

The documents below provide referential information as to the definition and usage of Warm Mix Asphalt:


WMA Presentations

The documents below provide several years of presentations by researchers about Warm Mix Asphalt: