Biologist Creates 'self-healing' Concrete

It's the world's most popular building material, and ever since the Romans built the pantheon from it some 2,000 years ago, we've been trying to find ways to make concrete more durable. Professor Henk Jonkers, of Delft University of Technology, in the Netherlands, has come up with an entirely new way of giving concrete a longer life. He explains, "We have invented bioconcrete -- that's concrete that heals itself using bacteria." The bioconcrete is mixed just like regular concrete, but with an extra ingredient -- the "healing agent." It remains intact during mixing, only dissolving and becoming active if the concrete cracks and water gets in.