The California Asphalt Pavement Association
Representing the asphalt pavement industry in California since 1953

Warm Mix Asphalt

The hottest thing in Hot Mix Asphalt

The asphalt pavement industry in California, working in conjunction with researchers and public owners, is moving aggresively toward a new pavement standard, "Warm Mix Asphalt," which promises many benefits, including reducing the consumption of fuel used to heat conventional Hot Mix Asphalt and widening the "window" for transporting and placing asphalt. This page contains the latest information and resources related to the Warm Mix Asphalt effort.

Warm Mix Asphalt project

WMA hits the mountains

Article in Oct. 26, 2009, issue of Asphalt Insider on Warm Mix Asphalt being utilized on a project in Lake Tahoe. Click HERE to go to the issue.

WMA Technical Working Group

A national effort

Click HERE to go to a website set up to gather information nationally about Warm Mix Asphalt.


Warm Mix Asphalt demonstration project at UC Davis

Different WMA technologies are put to the test

On April 7 & 8, 2010, a paving operation took place on the University of California, Davis campus. But this was no ordinary road project. A collaboration between Caltrans, the University of California Pavement Research Center (UCPRC) and the construction industry, the "Rubberized Warm-Mix Asphalt Test Track Construction" was intended to determine whether the use of technologies to reduce the production and construction temperatures of hot-mix asphalt influences performance of the mix. The project participants were (asphalt plants) Granite Construction, Bradshaw facility, and George Reed, Marysville facility. The paving contractor was Teichert Construction. The WMA technologies to be tested included: Advera WMA; Astec Double Barrel Green; Cecabase RT; Evotherm DAT; Gencor Ultrafoam GX; Rediset WMX; and Sasobit. See photos of the operation below.


Photo captions

TOP LEFT: Carl Monismith from UC Berkeley and John Harvey from UC Davis

TOP RIGHT: A roller moves in to begin compacting a test section.

MIDDLE LEFT: UCPRC Project Manager David Jones (left) keeps a close watch on the paving operation

MIDDLE RIGHT: The Heavy Vehicle Simulator, funded by Caltrans, will replicate vehicle loads on the test strips

BOTTOM LEFT: A UC Davis graduate student monitors and records the temperature in the mat.

BOTTOM RIGHT: Tom Herschbach from Teichert Construction (left) and Jack Van Kirk from George Reed, Inc.

Warm Mix Asphalt project

WMA on the North Coast

Caltrans newsletter article (March 2010) about Warm Mix Asphalt technologies used in a North Coast road project. Click HERE to read.


Caltrans WMA approval process


Click HERE to download a PDF copy of the April 11, 2011 Caltrans memo outlining the WMA approval process. To view the list of approved technologies, click HERE.

Warm Mix Asphalt project

WMA by S.F. Bay

Asphalt Insider article (Aug. 8, 2011), with links to addtional photos, of WMA project in Golden Gate National Recreational Area. Click HERE to read.

Caltrans contractor option memo


Click HERE to download Caltrans construction memo dated June 7, 2012 regarding contractor option guidelines for Warm Mix Asphalt.