Engineering researchers at Kansas State University have discovered a method for making concrete with waste products from biofuel production, replacing Portland cement as a primary ingredient. The process reduces the carbon footprint of concrete production by using recycled materials, and strengthens the concrete by more than 30 percent.

Most of the efforts to "green" concrete are aimed at finding a replacement for Portland cement, one of concrete's main ingredients. Civil engineers at Kansas State University (KSU) have concocted a way to use the waste products of biofuels to make a stronger concrete, which reduces the carbon footprint of concrete production at the same time.

The KSU researchers replaced the Portland cement with the ash from the waste products of biofuels, which is made from the waste products of agriculture - in this case, corn stover, wheat straw, and rice straw. All of these are used as feedstock for cellulosic biofuels, meaning they are derived from feedstock based on inedible waste plant material, instead of feedstock derived from seeds or grains of crop plants.

Since the production of cellulosic ethanol is expected to increase, so will the wastes resulting from those processes, say Feraidon Ataie, doctoral student in civil engineering, and Kyle Riding, an assistant professor of civil engineering. At present, this material doesn't have many other uses.

Ataie and Riding detailed their work in a scholarly article published in the Journal of Materials in Civil Engineering. After some experimentation, they determined that using the agricultural residue ash (ARA) to replace 20 percent of the cement by mass increased the concrete's strength by 32 percent.

For more information, visit k-state.edu.