Old tires make for stronger concrete

For some time now, crumbs of rubber from ground-up discarded tires have been used to produce a more resilient form of asphalt. Researchers from the University of British Columbia are taking things in a different direction, however, by using polymer fibers obtained from old tires to make concrete stronger.

Added to existing concrete (which is a mixture of cement, sand and water), the stretchy fibers bridge tiny cracks as they form, keeping them from becoming bigger. In lab tests, concrete with the added fibers was found to be over 90 percent more resistant to problematic cracks, as compared to conventional concrete.

What's more, the fibers only need to make up 0.35 percent of the total mixture.

Not only could the technology help keep tires from ending up in landfills, but it should also reduce the number of times that concrete structures have to be replaced. Given that cement production is a major source of carbon dioxide, the less often the material has to be used, the better for lessening the emission of greenhouse gases.

Led by civil engineering professor Nemkumar Banthia, researchers used the fiber-reinforced concrete to resurface the steps of UBC's McMillan building last month. Utilizing sensors embedded in the concrete, they are now monitoring it for factors such as strain and cracking – so far, the results are promising.

A paper on the project was recently published in the journal Materials and Structures.

Source: University of British Columbia