This article first appeared on edie.net on March 26, 2013.
Waste from biofuel could drive the production of more sustainable concrete through a pioneering closed-loop process. Researchers are experimenting with ways to produce cement that will absorb CO2 emitted from factory flues.
According to a report from Climate News Network, the University of Kansas is leading the work, by substituting some of the cement in a concrete mix with the by-products of biofuel production.
The by-product, lignin residue, is a woody substance produced from generating biofuel from cellulose waste such as wood chips and straw, which usually has to be burned or buried. When the Kansas team added 20% lignin waste to their cement, the subsequent chemical reaction delivered a concrete considered 30% stronger than traditional types.
Civil engineer Feraidon Ataie, one of the lead researchers on the project, said the process not only delivers a more sustainable alternative, but has several other benefits.
"If you use this in concrete to increase strength and quality, then you add value to this by-product rather than just landfilling it," he said. "If you add value to the by-product, then it is a positive factor for the industry. It can help reduce the cost of bioethanol production."
Other examples of by-product synergy in the cement industry include the use of slag from steel mills in the production process, which has been shown to increase production output by 10 percent and decrease nitrogen oxide emissions by nearly 40 percent.