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Engineers develop ‘self-healing’ concrete

A team of US engineers have come up with a form of concrete that can repair cracks by itself. All the material needs, the team claim, is water and carbon dioxide.

The concrete is designed to crack in small hairline fractures, rather than splitting with wide gaps, like traditional concrete.

Explaining the process, Victor Li, the E. Benjamin Wylie Collegiate Professor of Civil Engineering, commented: “It’s like if you get a small cut on your hand, your body can heal itself. But if you have a large wound, your body needs help. You might need stitches. We’ve created a material with such tiny crack widths that it takes care of the healing by itself. Even if you overload it, the cracks stay small.”

Tests on the material showed that it recovered nearly all it’s strength after a 3 per cent tensile strain, which means that the concrete was stretched to 3 per cent bigger than its normal size. This is significant enough strain to fracture tradition concrete or deform metal.

“We found, to our happy surprise, that when we load it again after it heals, it behaves just like new, with practically the same stiffness and strength. Self-healing of crack damage recovers any stiffness lost when the material was damaged and returns it to its pristine state. The material can be damaged and still remain safe to load,” explained Li.

“Our hope is that when we rebuild our roads and bridges, we do it right, so that this transportation infrastructure does not have to undergo the expensive repair and rebuilding process again in another five to 10 years,” he concluded.

To view a video of the concrete, click here.

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