Dr. Yusuf Çağatay Erşan, faculty member of Abdullah Gül University (AGU) Civil Engineering, created self-healing concrete by adding bacteria into the concrete.
Dr. Yusuf Çağatay Erşan succeeded at making self-healing concrete by packing the concrete with bacteria as part of his doctoral thesis carried out with a group of academics at Ghent University, Belgium between 2013-2016. In the research called "Bio-concrete," bacteria are added into concrete mixture after several processes after which bacteria fill cracks with limestone eliminating the need for maintenance and extends the lifespan of constructions. Moreover, the bio-concrete prevents corrosion of steel reinforcements in it, thus concrete's lifespan extends.
Bacteria added into the concrete heal cracks
Erşan said they are working to have a more optimum mixture of bio-concrete and informed about the self-healing process:
"Normal concrete contains sand, cement and aggregate. Bio-concrete also contains bacteria that can heal the concrete if needed. Bacteria are integrated into the concrete mixture in the form of dry powder like sand. They perform like a sort of vaccine against early or later cracks due to aging which could occur after the concrete hardens. Since we add bacteria in spore form, they are dormant until the concrete cracks or water leaks. As soon as the concrete cracks, with water getting in and nutrients dissolving, conditions become suitable for bacteria and they fill the cracks with calcium carbonate."
Bio-concrete is used in constructions in contact with water
Erşan said bio-concrete could be used in bridge legs, ports, submarine tunnels which are in contact with water or horizontal roads which hold water and it protects steel reinforcements in these constructions against corrosion. That is how the lifespan of concrete is extended, Erşan said: "Bio-granules used in the process also stop steel corrosion. They fix a crack, form a protective la
Concrete lifespan extends
Although the initial cost of bio-concrete is high, it is profitable in the long run as it eliminates operational and maintenance costs, Erşan said: "When we began the research in 2013, initial costs were around 1-2 thousand but we could bring the cost down ten times in our current work. However, they are still high for the market conditions. Yet again they are advantageous in terms of saving from future costs. One does not have to check the concrete regularly and spend extra money in case of cracks. Closing a road, tunnel, bridge for maintenance incurs high costs and hinders service, but bio-concrete eliminates all those costs. Moreover, their second value lie in the fact that they reduce costs by lengthening the lifespan of the concrete. Although their initial costs are high now, in later stages they prevent potential operational costs."
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