AMES, IOWA, U.S. — Soybean oil-infused asphalt was debuted during an open house at Iowa State University’s BioCentury Research Farm on Nov. 11, by two of the university’s engineering professors.
Christopher Williams, professor of civil, construction and environmental engineering, and Eric Cochran, professor of chemical and biological engineering, began working on the idea of manufacturing rubber with soybean oil.
With more research the idea progressed and was decided it would be best used to improve the performance of asphalt pavements. The researchers are closing in on the commercialization of a bio-based polymer that can replace the petroleum-based polymers currently used as the binding agent in asphalt.
The potential new use for soybeans is seen as a win for the Iowa Soybean Association and U.S. farmers due to recent trade issues and the increased spread of African swine fever (ASF) in China.
“Soybeans are highly dependent on international markets,” said Rolland Schnell, an Iowa Soybean Association (ISA) district director. “Any time we can use our product domestically, it gives farmers a little more certainty.”
Asphalt is extracted during the oil refining process, which can leave it weak and hard, causing a need for lubricants to be added back to the asphalt.
Cochran told the Iowa State Daily, “One aspect of how soybean oil-based rubbers are valuable is we found we can, very cost effectively revitalize hard and brittle asphalts.”
Cochran said there are about 1.6-billion pounds of oil used in the polymer binders annually from three market segments combined: polymer-modified pavements, pavement rejuvenation and road maintenance products.
Once commercialized, Cochran expects hundreds of thousands of tons of soybean oil could be utilized annually.
“We’re competing against petroleum-based polymers that cost between $2 to $4 per pound and whose key ingredients, butadiene, is largely imported from Asia,” Cochran said. “We’re offering a domestically-produced soy-based alternative that performs as well or better and will cost about $1 per pound.”
Testing of the bio-based polymer has now moved from ISU’s Bio-Polymer Processing Facility at the BioCentury Research Farm to the National Center for Asphalt Technology (NCAT) Test Track.
According to the Iowa Soybean Association, a 1.7-mile oval in Opelika, Alabama, U.S., the track is comprised of 46 main test sections sponsored on three-year cycles. The track is circled by a fleet of heavily loaded trucks resulting in 10 million equivalent single axle loads of traffic. The performance of each test section is closely monitored over a period of two years.
Participating in NCAT are 22 state departments of transportation, including the Iowa Department of Transportation, as well as 20 national companies. If tests go well, it could launch a broader reach and market for the product, Cochran said.
“Commercial sales come after the testing and regulatory hurdles have been addressed,” Cochran said. “If your NCAT demo goes well, you’ve essentially got 22 states that aren’t worried about allowing your product to be used, plus you could have companies that could be interested in buying the product. It’s good public relations if things go well.”