Waste Ash to Reinforce Concrete

 (Discovery News 3-30-2011) Concrete, the material making up tons of America's infrastructure, from bridges to roadways, unfortunately tends to crumble. But a new coating that is hundreds of times more durable than existing concrete shields could save the day -- and it's made from "flyash," the soot and dust waste that spews out of more than 450 coal burning plants in the United States every day.
The 130 million tons of flyash generated each year already poses a national disposal problem. The waste used to just be released into the air, falling where it may, until plants started collecting it. Now the ash gets partially recycled, but about 70 percent of it still ends up in landfills. Space is short, concrete has a need, and putting flyash to use supporting roads and other structures that need crumble-proofing is both effective and half as expensive as other concrete coatings.
According to Charles Carraher, a chemist from Florida Atlantic University and leader of the flyash study which was presented at Tuesday's 241st National Meeting & Exposition of the American Chemical Society in Anaheim, the ash could be used to reinforce rebar rods inside concrete as well as to repair damaged concrete. In lab tests, the flyash coating remained intact for over a year, while regular concrete began crumbling in days. It also withstood exposure to conditions far harsher than would occur in the real world, says Carraher in the press release, including acid concentrations in the air that are 100,000 times higher than in normal outdoor pollution levels.
EPA estimates put fixing our current concrete infrastructure at trillions of dollars in cost -- just repairing wastewater and drinking water systems alone is projected at $1.3 trillion, and that does not include any roads or bridges. Using flyash has huge potential to cut down on these costs, while simultaneously solving its own waste problem. 
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