REAL LIFE NEWS: CONCRETE, HEAL THYSELF
by Hazed
Concrete is the world’s most popular construction material, using for buildings, roads, bridges, reservoirs and dams. Over time it develops cracks, allowing water to seep in and corrode the concrete. But now scientists have come up with a self-healing concrete that can seal up those cracks to extend the life of the substance.
This self-healing concrete contains bacteria which produce limestone. They are activated by corrosive rainwater working its way in through micro-cracks, so they can patch them before they get large enough to cause damage.
The concrete is seeded with bacterial spores and the nutrients they feed on, but so long as they remain dry they will be dormant. It’s only when the rainwater seeps in that the bacteria start to feed on the nutrients, and produce the limestone.
This new concrete has been developed by microbiologist Henk Jonkers and concrete technologist Eric Schlangen, at Delft Technical University, the Netherlands.
“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.
“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, different types of concrete to see if this concept really works in practice.”
The team is hoping that they can reduce the cost of the self-healing concrete, and then they can begin outdoor tests in about six months, monitoring it to see how it works in the real world for at least two years. If all goes well they can then look into making it a commercial product.
Source: http://www.bbc.co.uk/news/science-environment-20121303
