Living Concrete Technology

The workhorse microbes are Bacillus spores, picked because they shrug off the harsh, alkaline inside of concrete. Mixed in with a food source, they ride out the dry years asleep.

When water and a crack reach them, they feed and lay down limestone, sealing gaps up to about a millimeter wide. The world pours a staggering amount of concrete every year, so even a modest gain in lifespan adds up to huge savings in repairs and carbon.