The human body is an amazing piece of engineering. Cut your skin, and the body recognizes the cut and starts a series of reactions that closes off the injury and heals the wound.
Taking a cue from the the body, researchers at the University of Michigan have developed concrete that also heals itself with chemical elegance.
Concrete cracks because, while it is very strong under compression, it does not do well under tension or flexing--it cracks and breaks.
This concrete is more flexible, however, due to its chemical makeup and as a result is well suited for use in highways, bridges and buildings where bending and flexing causes cracks.
With this concrete, even if it does micro-crack, exposure to a light rain shower causes the concrete to heal and the resulting concrete is as strong as the uncracked material.