While Congress works to approve highway funding, engineers are working on technology that will allow concrete to clean itself or better yet repair itself. In an article on The Christian Science Monitor, Phoebe Tollefson reports on this technology which has already been registered at the European Patent Office.
The material that allows for self-healing contains a limestone-producing bacteria that activates when wet and can remain dormant up to 200 years:
When a structure made of self-healing concrete develops a crack, water inevitably seeps in, prompting the bacteria to feed on calcium lactate in the concrete. The feeding process breaks down different minerals in the concrete and consumes oxygen from the air. This sets in place a process that converts the calcium lactate, which can be dissolved in water, to limestone, which fills the crack.