Concrete That Gets Stronger When It Cracks. Engineers Proved It. Why Are We Not Using It? скачать в хорошем качестве

Concrete That Gets Stronger When It Cracks. Engineers Proved It. Why Are We Not Using It?

Concrete That Gets Stronger When It Cracks. Engineers Proved It. Why Are We Not Using It? There is a version of concrete that bends. Not flexes slightly before cracking. Bends. Deforms under load without fracturing. When it does crack, the cracks are so small — less than sixty micrometers wide, roughly the diameter of a human hair — that water cannot penetrate them. And when it gets wet, those cracks seal themselves. It is five hundred times more resistant to cracking than normal concrete. Forty percent lighter. It looks identical to the material it could replace. It is called Engineered Cementitious Composite. And it has been sitting largely unused while the infrastructure that desperately needs it continues to deteriorate. A structurally deficient bridge is not a bridge about to collapse. It is a bridge with at least one key structural element in poor condition. There are more than forty-two thousand of them in the United States. Every day, American drivers cross them one hundred and sixty-eight million times. The reason most of them are deteriorating is not age. It is concrete. Specifically, it is the fact that ordinary concrete is brittle. It does not bend. It cracks. And once it cracks, water gets in. Salt gets in. Steel corrodes. And a structure built to last a hundred years begins failing at thirty. The question of why the material that solves this problem is not already holding up every bridge in America is one of the most instructive stories in modern materials engineering.