As concern for our environment grows, sustainable materials and new production technologies are becoming even more important to the environment and the economy. Hot-mix asphalt (HMA) is a highly recyclable material that typically contains 15 percent of recycled content, but new technologies are being developed that double the recycled content of asphalt to 30 percent while lowering the production and placement temperatures. These technologies, known as warm-mix asphalt (WMA), are produced at temperatures 50 to 100 degrees Fahrenheit less than traditional HMA product, delivering benefits in energy savings, air quality improvements and increased paving performance.
Local companies are utilizing the new WMA technologies that lessen the impact on our environment and improve pavement performance. In 2010, one company added the required equipment to make four of its asphalt plants capable of WMA production and has since placed more than 80,000 tons of WMA.
Brandon LeFevre, operations manager for Staker Parson, reports that the company uses a foaming method manufactured by Maxam Equipment, Inc., to produce WMA. "The system uses a patented foaming gun to inject a very small amount of water into the AC line prior to entering the mixing drum," LeFevre says. "As the water is introduced into the asphalt binder, it turns into steam and expands, creating asphalt foam. The foaming increases the volume of the liquid, which then coats the aggregate particles and reduces the stiffness of the mix so that it is more workable. Once in the paver, the WMA is placed the same way as traditional HMA."
Staker Parson has produced more than 50,000 tons of WMA at its Point East Hot Plant located in Lehi, Utah. Most of the material has been placed on the Utah Department of Transportation (UDOT) I-15 CORE project. UDOT permitted WMA to be incorporated into the project by allowing the asphalt to be placed at a reduced temperature and required that the asphalt still meet the high standards for material quality, density and performance specifications.
"To date, all the quality and density incentives from UDOT on the I-15 CORE project have been achieved at a rate that exceeds historical levels achieved for traditional HMA," he says. LeFevre is hopeful that owners and agencies will continue to develop permissive specifications that allow the use of new WMA technology in place of conventional HMA. This continued advancement of WMA will surely lead to benefits for companies, customers, the environment and the community.
As president of Staker Parson Companies South Region, Mike Kurz is responsible for the overall management of all locations from Kaysville, Utah South to Tucson, Ariz., and all of Nevada. During his time at Staker Parson, thousands of miles of Utah roadways, parking lots and driveways have been constructed or rebuilt with crews and office personnel under Mike's supervision.