Concrete is the most widely used building material in the world

Concrete is the most widely used construction material in the world.It can be found in swathes of city pavements,bridges that span vast rivers,and the tallest skyscrapers on earth.But this sturdy substance does have a weakness:it’s prone to catastrophic cracking that costs tens of billions of dollars to repair each year.But what if we could avoid that problem,by creating concrete that heals itself?