Half of all structures in the world are made of concrete. But, the world’s leading building material has an inherent flaw – it cracks! Very small cracks are anticipated and those under 0.2mm do not cause direct loss of strength. The problems arise over long periods of time, when water and chemicals gain access into the tiny cracks causing the concrete to expand and contract and corrode. This can ultimately cause building collapse.
Now a microbiologist and a concrete technologist in the Netherlands, have created an advanced ‘smart concrete’. By adding bacterial spores and nutrients into the original concrete mix, they have produced a material that heals its own cracks once it comes into contact with rainwater. It works because the bacteria, which are harmless, lie dormant until activated by rainwater to consume the nutrients. In this process they produce calcium carbonate, a naturally-occurring mineral which forms limestone. It then bonds to the concrete and seals the crack.
It’s early days and more experimentation is required to improve and scale the process for commercial use. But potentially, the new material could reduce maintenance and prolong the life of concrete structures dramatically.