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PRI's Environmental News Magazine

Greener Concrete

Air Date: Week of May 3, 2013

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Qainat (Kine-att) Khan reports in this LOE Science Note about a greener, stronger concrete developed by Kansas State University professor Kyle Riding's team of researchers.

Transcript

KHAN: Every year we use seven billion cubic meters of concrete. That’s one cubic meter for every person on Earth. And producing that much concrete also produces up to eight percent of carbon dioxide emissions worldwide. So researchers at Kansas State University thought, well, if we could find a way to make concrete go a lot farther, we could reduce the total concrete production and cut greenhouse gas emissions. Kyle Riding is an engineering professor at KSU and he and his team have created a concrete mix that does just that.

Most of the carbon dioxide in the concrete process comes from making cement. Cement’s the most important component in concrete, and it needs lime, which you make by heating calcium carbonate until it breaks down into lime and carbon dioxide. So to reduce carbon dioxide emissions, you need to use less cement in your concrete mixture. Riding’s team did this by replacing 20 percent of the cement in the concrete mix with silica. When silica's mixed into cement, it reacts to make concrete stronger and more durable. This is what ancient Romans did when they mixed their lime with volcanic ash.

And Riding’s team found this high silicate miracle compound in an unlikely place: the landfill. The substance - called high lignin residue - is the waste from a process used to make cellulosic ethanol. But this organic material is usually just trashed. So Riding’s concrete mixture could help to solve two problems: it could cut carbon dioxide emissions and reduce landfill waste. Which just goes to show, less can be more. That's this week's note on emerging science, I'm Qainat Khan.

 

Links

Kansas State University

Green Building News

 

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