If you forced the center of a 10 foot piece of concrete to bend by three percent, and it didn’t break, the bow in it would be three-and-a-half inches lower than the ends. (Photo by Nicole Casal Moore)
It should break, or at least severely crack. But a new kind of self healing concrete will take that kind of abuse and actually heal itself. The material is being sought after for bridges, roads and other infrastructure projects where reinforced concrete is exposed to harsh weather and salts.
The concrete gets its properties from an engineered cement composite (ECC) developed over a 15 year period at the University of Michigan. The ECC concrete recovers its original strength after the strain and behaves like new when stressed again. The cracks resulting from the stress heal up when exposed to water and carbon dioxide leaving a thin white scar. Cracks that heal don’t permit water and de-icing salts to enter the concrete where they can degrade the reinforcing bars.
University of Michigan (2009, April 24). Self-healing Concrete For Safer, More Durable Infrastructure. Retrieved May 14, 2009, from ScienceDaily.
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