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 Guidance Memo (PDF)
- WMA Frequently Asked Questions (PDF)
- WMA Position Memo (PDF)
- WMA MnROAD Brief (PDF)
- TERRA WMA Fact Sheet
WMA Presentations
The documents below provide several years of presentations by researchers about Warm Mix Asphalt.
- Warming up to WMA, Michigan Tech, 2011 (PDF)
- WMA Specification and Policy Document Development in Minnesota, TRB 90th Annual Meeting, 2011 (PDF)
- Introduction to Warm Mix Asphalt, North Dakota Asphalt Conference, 2010 (PDF)
- WMA Performance at MnROAD, MAAPT 57th Annual Asphalt Conference, 2010 (PDF)
- Intelligent Compaction: History, Projects & Analysis; 57th MAAPTH Annual Asphalt Conference, 2010 (PDF)
- WMA at MnROAD- Asphalt Pavers, 53rd Annual Asphalt Contractors' Workshop, 2009 (PDF)
- WMA at MnROAD- Chris Miller Hardrives, 2009 (PDF)
- WMA at MnROAD- Pavement Conference, 2009 (PDF)