InTrans / Apr 26, 2019

New technology developed at Iowa State may boost use of recycled materials in asphalt

Chris Williams

A new technology developed by Iowa State University (ISU) engineers that has the potential to significantly boost the use of recycled materials in asphalt is earning international attention for its promising future impact to the transportation industry.

Chris Williams, director of the Asphalt Materials and Pavements Program and ISU civil engineering professor, Eric Cochran, ISU chemical and biological engineering professor, and Nacu Hernandez, ISU chemical and biological engineering scientist, developed a method to reduce the separation of ground tire rubber (GTR) in asphalt by mixing GTR with a polymer additive before blending it with asphalt.

Energy & Fuels, a publication of the American Chemical Society, recently published a paper and highlighted the results of their research on it. The paper, also authored by doctoral candidate Brittany Hallmark-Haack, has since gotten attention in the chemistry and transportation industries around the globe.

This new technology has the potential to reduce carbon dioxide emissions and energy use while recycling thousands of metric tons of both discarded tires and rubber each year. Right now, the US generates 270 million waste tires each year, about 10 percent of which is put in landfills and other disposal areas.

It also has an economic benefit, as using GTR is less costly than asphalt alone and virgin styrene-butadiene-styrene (SBS) elastomers.

The engineers’ work has built on years of study on biobased materials, e.g. soybean based rubbers, and their use in asphalt pavements.

The research is promising but additional tests are underway to determine a life-cycle analysis and low temperature performance grade. The team is preparing to partner with industry leader Lehigh Technologies to conduct studies to evaluate the ability to scale the technology for commercial use.

The Energy & Fuels paper can be read here, and a summary can be found here.