Bacterium bubbles patch damaged concrete
A series of handy bacteria can mend holes and even improve structures from the inside with materials that are included in the concrete.
Roads, bridges, tunnels, and dams are made of concrete that is constantly subjected to wear and tear, which will, over time, break down the otherwise sturdy building material. When cracks emerge, water and harmful substances can enter deep into the structure and destroy it from the inside, so it is important to make repairs in due time. Hence, scientists have taught a team of tiny craftsmen, that are always on duty, to take care of the maintenance.
Bio- concrete has been enriched with hibernating bacteria and a natural, nitrogenous material known as urea. The bacteria are revived when water dissolves the capsules in which the microbes are located. The bacteria set out to fill the crack layer by layer, using urea and calcium, which exist naturally in the concrete. The only byproduct of the process is ammonia, which dissipates. Once the crack is healed, the bacteria go back into hibernation, and wait for the next time they are activated.
The job can be done by several different bacterium species with metabolisms that can convert urea and survive for hundreds of years in the extremely alkaline concrete environment. Experiments with the Bacillus subtilis bacterium have shown that the deposits will not only repair the cracks, they also improve the strength of the concrete.