Evotherm

As California’s and the nation’s energy costs grow and new emissions standards loom on the horizon for the paving industry, warm-mix asphalt technology like Evotherm is emerging as a clear preference for asphalt producers and customers alike.

On September 28, 2006, George Weir’s Escondido Asphalt & Paving became the first company to use Evotherm warm-mix asphalt technology in California.  The City of Escondido contracted the paving project for a new 12,000 square foot parking lot on West Washington Avenue in its city using approximately 250 tons of warm-mix asphalt produced in Weir’s plant.  Weir’s plant was able to produce the warm-mix using Evotherm without any significant changes to the asphalt plant or the production process. 

Evotherm technology enables asphalt mixes to be produced and applied at temperatures more than 100 degrees lower than hot-mix applications.  Lower temperature requirements during production enabled a 55 percent reduction in fuel consumption, a 46 percent reduction in greenhouse gases, a 58 percent decrease in nitrogen oxides that lead to photochemical smog, and an 81 percent drop in acid rain causing sulfur dioxide.  With optimum lay-down and compaction temperatures around 160 degrees, Evotherm also achieved a 40 percent overall reduction in job emissions.

During the paving project, which was attended by state and local government officials, the city’s paving contractor J.D. Paving laid hot-mix asphalt side by side with the warm-mix asphalt.  Both batches followed the same specifications.  Following the compaction process both mixes met the 95 percent design standard, while the warm-mix asphalt actually surpassed the compaction of the hot-mix by more than a percentage point, by achieving close to 97 percent compaction.  The city is also expecting the additional benefit of a longer life of the pavement and decreased maintenance costs over the lifetime of the project.    

City officials were pleased with the successful demonstration.  “This is the first time Escondido has ever used warm-mix asphalt on one of our projects,” stated Mayor Lori Holt Pfeiler. “This temporary fire station and parking lot are vital to serving our citizens and the use of warm-mix asphalt technology can allow us to meet these needs while lessening the impact of construction on the environment.”

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