Newspaper article The Christian Science Monitor

How Self-Healing Concrete Could Fortify America's Crumbling Roads

Newspaper article The Christian Science Monitor

How Self-Healing Concrete Could Fortify America's Crumbling Roads

Article excerpt

As Congress navigates another last-minute scramble to approve funding for the nation's highways ahead of a July 31 deadline, engineers far-removed from the Capitol Hill gridlock are hard at work improving the stuff that sustains our nation's roads and bridges: concrete.

Recent innovations point to stronger and higher-performing highways and bridges in the future. Some products are already on the market; others are a long way off.

It may sound far-fetched, but the technology exists for self- healing concrete. The auto-mending material contains limestone- producing bacteria that activates when wet. The bacteria can lie dormant for up to 200 years, according to the European Patent Office, where the technology is registered.

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.

"This is kind of 'The Jetsons' stuff," says Georgene Geary, with a laugh. Ms. Geary is principal engineer at GGfGA Engineering in Georgia, and chairs the Task Force on Nanotechnology-Based Concrete Materials at the Transportation Research Board in Washington.

"This is the future," she says.

Hendrik Jonker, a microbiologist in the Netherlands who owns the patent to the technology, came up with the idea by considering how the human body repairs broken bones through mineral processes. The process for concrete works on a crack of any length, as long as it is no wider than 0.03 inches, according to the European Patent Office.

New technology also opens the door for self-cleaning concrete. Engineers such as Kimberly Kurtis, professor at the Georgia Institute of Technology in Atlanta, are studying ways to use light as a catalyst for cleaning the surface of concrete or binding pollutants in the surrounding air. …

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