Self-Healing Concrete Could Rid Sidewalks Of Cracking

Concrete Crack

Photo: Flickr/M.Markus

Researchers from Delft Technical University in the Netherlands have created a self-healing concrete that may be available within the next two or three years if outdoor tests prove successful, reports the BBC.Concrete is the most popular building material, but it is prone to cracking. Concrete cracks for a number of reasons, including temperature fluctuations that make the concrete expand and shrink. This stress on concrete creates micro-cracks that do not directly weaken the concrete, but allow water to seep into and damage the concrete over time.

While concrete is relatively inexpensive to install, maintaining it is much more expensive.

To help decrease repair costs, microbiologist Henk Jonkers and concrete technologist Eric Schlangen are working on a self-healing concrete. They mixed bacteria spores from the genus Bacillus with nutrients that are activated by water. So, when the water hits the bacteria, they feed on calcium lactate to make calcite, one of the two primary components of limestone.

“In the lab we have been able to show healing of cracks with a width of 0.5mm – two to three times higher than the norms state,” Dr. Jonkers explained to BBC.

An outdoor test of this concrete is currently underway and will be monitored for two years. In theory, when  micro-cracks occur in the concrete, rainwater will seep into the concrete, activate the bacteria, and fill in the cracks with limestone.

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