Microbial Concrete and Influence of Microbes on Properties of Concrete

The concrete is very commonly used for the structures, roads, monuments and modern buildings despite weak in tension having negligible ductility and less resistance to cracking. As the concrete structures most of the times are exposed to variant weather / atmospheric conditions may develop surface deterioration, even invisible cracks may also develop on the surface with passage of time. The microbes in concretes may help mineralization to introduce calcium carbonate precipitation is called microbiologically induced calcite precipitation (MICP). This MICP is highly impermeable in nature and used to remediate the cracks in building materials. The precipitated calcite layer improves the concrete performance, do heal the surface and is corrosion resistance too besides being used as water purifier. In this paper the various species of microbes which affect the behabiour of mortar specimens and performance of concrete in terms of compressive / flexural strength, efficiency, self healing characteristics of specific bacteria when introduced with concrete, called microbial concrete is studied and reviewed. The literature review reveals that when Bacillus sp. CT-5 as microbe is used, the cement mortar compressive strength is increased by 36 % [14, 22, 37, 44].