New Zealand University develops bacteria that repairs cracks in concrete

A team at the University of Waikato in New Zealand has developed a form of self-repairing concrete. 

The process uses what is called "solid-state fermentation" to fill cracks as they develop.

Waikato researchers Aydin Berenjian and student Mostafa Seifan add microorganisms and nutrients to the initial mix. These then create calcium carbonate when exposed to the air by cracking. 

Berenjian said the ability of the cells to keep producing calcium over time was crucial: "With the help of the unique fermentation system and nanobiotechnology, we have engineered a process that makes the calcium carbonate production very efficient even in a harsh environment like concrete."

Lab testing has shown that the bio-concrete is more durable than traditional concrete but the barrier the cost is currently NZ$200 (US$145) a cubic metre. 

The product will now be tested on a larger scale. Berenjian said: "We have had a lot of interest and our work has been thoroughly reviewed and published. It has huge potential for a range of other materials, industries and uses worldwide." 

Other researchers have previously developed similar self-healing concrete. UK contractor Costain is testing numerous techniques. A professor from Dutch university TU Delft has mixed asphalt with fragments of steel wool. And Binghamton University in New York State has developed a way to use fungus to heal cracks.

Images courtesy of the University of Waikato

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