Smith is working under the direction of Dunja Peric, associate professor of civil engineering.
"Kansas is strategically positioned for using lignin to stabilize unpaved roads," Peric said. "Kansas is located in the midst of the Great Plains, which is one of the largest wheat producing areas in the world. In addition, the construction of the nation's first commercial-scale cellulosic ethanol plant has recently begun in Hugoton."
For his research, Smith takes soil and mixes it with different amounts of water and lignin. He is testing five different lignin concentrations -- 2 percent, 4 percent, 6 percent, 9 percent and 14 percent -- to understand how different levels of lignin affect the soil cohesion and, consequently, road erosion.
Smith then lets the mixture dry in a controlled environment for different periods of time to understand how much it increases the strength of the samples. Other members of Peric's research team have been testing the strength of lignin samples immediately after they are mixed rather than allowing them to dry.
Once the materials are dry, Smith uses a direct shear device to determine the strength of the different mixtures. The direct shear device simulates the stress that unpaved roads experience when cars and heavy machinery drive on them.
"When vehicles drive on unpaved roads, there is a lot of dust that is thrown into the air," Smith said. "In addition, travel is impaired because of raveling and washboarding, which are forms of soil collapse on the top surface of the road. These are all things that can be mitigated by lignin because it holds the soil particles together and in place."
Based on early results, the materials with lignin concentrations of 4 percent, 6 percent and 9 percent show the highest strength benefit
|Contact: Dunja Peric|
Kansas State University