Self-Destructing Bacteria Heals Cracked Concrete

cracked sidewalk photo

Photo by apasciuto via Flickr Creative Commons

Could self-healing concrete be the answer to keeping sidewalks and structures in tip top shape and shrink the carbon footprint of concrete production? It's an issue we've brought up before, when Michelle Pelletier, a master's degree candidate at University of Rhode Island, came up with a paint for concrete that helps it self-heal. Now there's a new high-tech solution, using bacteria that comes complete with a self-destruct gene. Students at Newcastle University have created a new bacteria that can act as "glue" for cracked concrete.

According to GizMag, the bacteria is triggered to start germinating when it senses the specific pH of concrete, reproducing to fill in the crack until they hit the bottom of the fissure and start to clump.

"This clumping activates the cells to differentiate into three types: cells which produce calcium carbonate, cells which become filamentous to act as reinforcing fibers, and cells which produce a Levans glue which acts as a binding agent. The calcium carbonate and bacterial glue combine with the filamentous cells, ultimately hardening to the same strength of the surrounding concrete to form what the researchers have dubbed "BacillaFilla" which knits the concrete structure together again."

The new strain of bacteria comes complete with a self-destruct gene that keeps it from germinating anywhere but in contact with concrete. Because they're programmed to swim down into cracks in concrete and can't survive in the environment, the bacteria is unlikely to do anything worrying, like take over the world.

By helping to keep concrete intact, the new self-healing solution could potentially trim concrete production, thus trimming the carbon emissions created by one of the most widely used building materials in the world.

Joint project instructor Dr Jennifer Hallinan emphasizes the point: "Around five per cent of all man-made carbon dioxide emissions are from the production of concrete, making it a significant contributor to global warming. Finding a way of prolonging the lifespan of existing structures means we could reduce this environmental impact and work towards a more sustainable solution."

The nine students working on the new BacillaFilla entered their project in MIT's iGEM competition -- over 130 teams took part, and BacillaFilla took home the Gold prize. We have to wait and see if this has a future in real-world settings, but the idea of using bacteria to reduce our concrete use is certainly interesting.

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