Bacteria could make concrete repairs a thing of the past

Scientist in the Netherlands have come up with a self-healing concrete that can seal cracks and prevent air and water from causing reinforcement to corrode.

Developed by the Delft University of Technology, the concrete uses bacteria called extremophiles, which thrive in alkaline conditions and produce copious amounts of limestone to fill any cracks.

The bacteria are added to the concrete as it is being mixed, but to prevent them from being activated they are sealed in ceramic pellets a few millimetres wide. They then lie dormant - for up to 50 years - in the set concrete until a crack forms, which opens up the pellets and allows water to seep in. The bacteria then begin to feed, combining calcium with oxygen and carbon dioxide to form calcite which seals the cracks, returning the bacteria to their dormant state.

According to the Delft University of Technology the self-healing concrete will lead to enormous savings on maintenance and repair costs and, because it is longer lasting it will result in lower demand for cement with the knock on effect of lower CO2 emissions.

The team in the Netherlands has successfully trialed the technology and is now in the process of developing it to make it commercially viable.