Dutch Researchers from Delft Technical University in the Netherlands have developed a concrete that can repair itself using bacteria.

Concrete is the most-used building material in the world but is prone to fractures and cracks which can weaken support. Concrete currently needs to be reinforced with steel and in some cases fixed or replaced when cracks expand too much. However, researchers from Delft Technical University – Henk Jonkers, a microbiologist and Eric Schlangen who specializes on material development, have been working for the past several years on a new type of concrete which has self-regenerative properties.

In testing Jonkers and Schlangen mixed bacteria into a cement mixture and after a month they found the spores of three particular bacteria where still viable. They then added a harmless bacteria known as Bacillus Genus to the concrete which remained dormant until rainwater entered the cracks which occur naturally inside concrete.

In order to develop, the bacteria used the nutrients the researchers incorporated into the cement (calcium lactate – a component of milk). According to Dr Jonkers:

“In the lab we have been able to show healing of cracks with a width of 0.5mm. Now we are upscaling. We have to produce the self-healing agent in huge quantities and we are starting to do outdoor tests, looking at different constructions and different types of concrete”

The main challenge of the self-healing project is to ensure the healing agent can survive the mixing process. In order to do that the researchers had to coat the healing agent particles which is an expensive process. They are hoping that they will be able to reduce the cost  within the next six months. After that time a new series of testing should begin – this time outside the laboratory in real world conditions. The researchers are already in discussions with several companies to examine the commercialization of the technology – something that might take at least two more years.

More information about the self healing concrete can be found on the Delft Technical University website.

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