A Critical Review on Bacterial Concrete

Concrete, a strong, durable material composed of cement, aggregate and water, is the most used building material in the world. Concrete has an ultimate load bearing capacity under compression but the material is weak in tension. So, it cracks under loading. That is why steel bars are embedded in the concrete for the structure to carry tensile loads. Steel bars takes the load when concrete fails under tension. The concrete protects the steel reinforced bars from the environment and prevents corrosion. However, the cracks in the concrete form a major problem which affects the durability of the structures. Water and other salts seep through these cracks, corrosion initiates, and thus reduce life of concrete. So there was a need to develop a bio material, a self-repairing material which can remediate the cracks and fissures in the concrete. The goal of our study is to apply bacterially precipitated CaCO3 to heal the cracks in concrete. This technique is highly desirable because microbial activities are pollution free and natural. In this study, a Bacillus bacterium (Bacilluspasteuriior Bacillus subtilus) has been used to induce CaCO3 precipitation. This phenomenon is called Microbiologically Induced Calcite Precipitation (MICP). Use of these bio mineralogy concepts in concrete leads to invention of new material called-Bacterial concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete.