ISU researchers ‘pave road' for novel lignin applications

By Bryan Sims
Researchers at the Iowa State University Department of Civil, Construction and Environmental Engineering are looking at ways to extend the longevity of Iowa's road infrastructure by experimenting with lignin, a coproduct of lignocellulosic ethanol production, to see if it could be used as a viable soil stabilizing agent.

"Lignin acts as a resin, and it's a natural binding agent to soil," said Halil Ceylan, the department's assistant professor who is leading the project. "If we continue to increase the traffic volume, we need to improve our road system so that we can be competitive when carrying our goods from one location to another in a speedy and safe manner."

The research team conducted several soil tests with lignin supplied by Grain Processing Corp., a 10 MMgy corn-based ethanol plant in Muscatine, Iowa. The lignin was added to various oxidized and non-oxidized soils collected from soft clay and glacial till deposits that cover the state. Lignin also acts as an effective dust suppressant on the surface of roads, which alleviates health concerns in rural areas, according to Ceylan.

The effort is partially supported by a $93,775 grant from the Grow Iowa Values Fund, a state program that promotes economic development. The Iowa Highway Research Board, Grain Processing Corp. and ISU's Office of Biorenewables Programs also supported the project.
Research in this area isn't new for the department. Studies for the pulp and paper industry in the 1950s showed lignin to be a natural cementing agent that could be of value for soil stabilization, Ceylan said.

"County engineers are extremely excited about our research for soil stabilization purposes," Ceylan said. "We will soon be doing some additional proposals on the utilization of lignin for dust control purposes, as well. We're even more interested in that topic than soil stabilization, but they work hand-in-hand."