Self-Healing Concrete

When exposed to varying temperatures, water, and stress, concrete develops tiny undetectable cracks that can spread and threaten its integrity until eventually it must be replaced. Self-healing concrete offers significant economic and environmental benefits. The goal of this project is to investigate the feasibility of using bacteria as a self-healing additive, and to design a plant for producing self-healing concrete. The concrete designed by the team includes dormant bacteria that are reactivated by water entering a crack. The bacteria naturally produce calcium carbonate, which seals the cracks resulting in a stronger, longer-lasting concrete. The team designed a system of bioreactors to cultivate the bacteria, Bacillus subtilis, which is added to lightweight aggregate, a component of concrete. The team also designed a plant to produce the cement necessary to make concrete. This design involves balancing the energy needs of several large crushers and grinders, a heating and cooling system, and a large kiln. The cement and aggregate are combined with water to form self-healing concrete.