Road Ready

Rolland Schnell, a Newton area farmer and past president of Iowa Soybean Association, pauses for a portrait at the NCAT Test Track in Auburn, Alabama.

Soy-based asphalt shows promise at test track

BY JOSEPH L. MURPHY

The success or failure of a project is often determined on the test track. Take the Daytona 500 as an example. Teams arrived weeks before the race for exhaustive testing before the big event. The race teams know a turn of the wrench can be the difference between the checkered flag and not even qualifying.

In order to research the viability of soy-based, biopolymer asphalt, an Iowa farmer recently traveled to the National Center for Asphalt Technology (NCAT) in Auburn, Ala. Joining a group of engineers, scientists and consultants, the team found the new product is a success in every definition of the word.

“Like biodiesel, this is another opportunity to have a value-added product here at home,” says Rolland Schnell, farmer and former Iowa Soybean Association (ISA) director. “These types of products increase the profitability of raising soybeans and decrease the cost of animal production.”

About a decade ago, ISA directors voted to use $125,000 as seed money matched by the United Soybean Board (USB) to build a pilot plant at Iowa State University (ISU) that experimented with the production of asphalt using biopolymers produced with soybean oil. After years of work, high oleic soybean oil was used as a binder to hold aggregates together and make asphalt.

“I'm excited because when you start in a lab, you have a dream,” says Chris Williams, a professor in the department of civil, construction and environmental engineering at ISU. His team has worked on developing the product since the beginning. "To see this dream being realized today is exciting. I truly believe this is going to create immense value for the people of Iowa and across the United States."

The polymer offers a lower-cost, less volatile and cleaner alternative to the traditional petroleum-based binding agents used in asphalt. The soybean oil also increases the reuse rate on asphalt grindings from 17% to over 30%, according to USB data.

“This is a project that was started several years ago, and now we have seen it taken from the theoretical to application,” Schnell says.

Test samples of asphalt are cataloged and categorized during the testing process.

Track testing

NCAT was established in 1986, as a partnership between Auburn University and the National Asphalt Pavement Association (NAPA) Research and Education Foundation. The goal was to provide practical research and development to meet the needs of maintaining America’s highway infrastructure.

“What they do here is realistic in an accelerated, timely manner,” Williams says. “This partnership allows us to project our market opportunities to a much broader audience.”

NCAT ensures the industry’s ability to provide pavements that are durable, sustainable, quiet, safe and economical. Industry sponsors fund research on the 1.7- mile oval in 200-foot test sections. The real-world laboratory allows experimentation while avoiding the risk of failure on actual roadways.

“There is a whole lot more to a blacktop road than I ever dreamt about,” Schnell says of his time at the test track. “By being at the track and seeing the results, it gives me confidence the soy-based asphalt is equal to or superior to other asphalt.”

More than 4 million miles of paved roads in the U.S. require significant upkeep, opening the door to increased opportunities for high oleic soybean oil and soy-based asphalt for years to come.

The initial, three-year test for the soy-based asphalt is expected to be finished this fall, according to Randy West, NCAT director. After the test, 10 million equivalent single axle loads (ESAL) will have passed over the asphalt test section. ESAL converts damage from wheel loads of various magnitudes and repetitions to damage from an equivalent number of “standard” or “equivalent” loads.

Randy West, NCAT director

“That is a way for us to normalize truck traffic to an 18,000-pound axle load,” West says.

Researchers at NCAT are monitoring the performance of the product, looking for things like rutting and cracking.

“Over the 15 months, it has performed perfectly, and we don't expect there to be any changes between now and the conclusion of the 10 million ESAL cycle," West says.

The average life span of asphalt depends on traffic use and the environment. Still, data suggests the national average for asphalt pavement is about 15 to 20 years, according to NCAT.

“The key benefit of the soybean polymer is about rutting resistance and it has some benefit in cracking,” West says.

According to NCAT officials, cracking happens over the lifespan of the asphalt. Further testing outside of the current three-year test will be needed to determine the longevity of the soy-based asphalt.

A sign on the section of the test track where soy asphalt is being tested.

“The way it is performing on the test track is a reassurance and a verification that the new soybased binder for asphalt is going to be successful in many ways,” Schnell says. “Not only with cost but in endurance and flexibility. There is no reason why it won’t be implemented, we just need to get the wheel rolling.”

Hearing from NCAT researchers and watching the soy-based asphalt withstand the loads of trucks testing the durability of the product, he adds, he felt proud.

“This makes me feel confident that the soy future is bright,” Schnell says, while standing on the soy asphalt test section at the track. “This is not going to be an overnight deal where we see increased profitability. It may not be in my farming career, but the longterm profitability of soybeans is in good hands with things like this.”

Contact Joe Murphy at jmurphy@iasoybeans.com.