Concrete is the most popular building material. It was invented by the Romans over 2,000 years ago. However, no matter how carefully it is mixed or reinforced, all concrete eventually cracks, and under some conditions, those cracks can lead to collapse.
"The problem with cracks in concrete is leakage," explains professor Henk Jonkers, of Delft University of Technology, in the Netherlands. "If you have cracks, water comes through -- in your basements, in a parking garage. Secondly, if this water gets to the steel reinforcements -- in concrete we have all these steel rebars -- if they corrode, the structure collapses."
Hendrik Jonkers, a microbiologist at the Delft University of Technology in Netherlands, has come up with a remarkable invention that has the potential to increase the lifespan of concrete and which will rid us of all of our building repair woes. Bio-concrete, as he calls it, is normal concrete with special bacteria mixed in it. These bacteria are actually limestone-producing bacteria and when mixed with concrete, they can make the concrete to 'heal itself' where cracks form. It is an incredible invention.
The mechanism involves the bacteria Bacillus pseudofirmus or Sporosarcina pasteurii. These bacteria thrive in alkaline environments and are found in lakes near volcanoes. When they come in contact with water and feed on calcium lactate, they produce limestone. This limestone fills up the crack in the concrete.
