Ottawa scientist builds a better concrete

The new concrete is to be used on the Seaway International Bridge near Cornwall, Ont., in 2011. (Canadian Press) An Ottawa scientist has developed a new, stronger type of concrete that may adds years to the lifespan of Canada's bridges. Daniel Cusson, the scientist leading a research team studying the new concrete, said the key is using shale sand that evenly retains water, making it less permeable. Normal versions of concrete — made from cement, sand, and other additives — are more prone to erosion from substances like road salt.

"The salt and moisture can diffuse and reach into the pores of the concrete and reach the re-enforcements," Cusson said. "But our concrete has a low permeability … it's very dense."
The concrete is being developed in a National Research Council lab, and so far tests have proven the concrete's strength. It is set to be used on improvements to the $75 million Seaway International Bridge near Cornwall, Ont., in 2011.

Cusson said his concrete is more expensive than regular mixtures, but he expects it to last up to 60 years, which could save millions down the line. "The concrete virtually does not crack," Cusson said.
Glenn Hewus, senior vice president of engineering at Canada's Federal Bridge Corp. Ltd., said he's excited to put the new concrete to use.

"In terms of maintenance, in terms of longevity, in terms of repair, this concrete is a drastic step up from what we have now," Hewus said.

The NRC lab's next challenge? Developing a concrete that can withstand a dynamite blast.

Read more: http://www.cbc.ca/technology/story/2010/12/23/ottawa-new-concrete-123.html#ixzz18zdEepy1