Warm Mix Asphalt

We are advancing pavement design, construction and maintenance through pavement and materials research, implementation projects and practitioner support.

We invite you to explore our research and testing facilities. MnROAD, our cold weather pavement testing center, works in conjunction with the MnDOT Materials Lab located in Maplewood, Minnesota.

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

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.