Effect of Bacillus Aerophilus on Concrete

Concrete is widely used in construction. Some of major drawbacks are Cracking and Seepage .Cracks form an open pathway to the reinforcement and can lead to durability problems like corrosion of the steel bars. These cracks should be repaired because they can reduce the service life of the structure. As synthetic polymers, currently used for concrete repair, may be harmful to the environment, the use of a biological repair technique is investigated in this study. Bacterial concrete, as the name indicates is an improvisation provided to cement using living microbes which are capable of doing so. Ureolytic bacteria such as Bacillus Aerophilus are able to precipitate CaCO3 in their micro-environment by conversion of urea into ammonium and carbonate. The bacterial degradation of urea locally increases the pH and promotes the microbial deposition of carbonate as calcium carbonate in a calcium rich environment. These bacteria have properties of bio calcification can secrete calcium carbonate as an extra cellular product thus filling the pores and the cracks internally making the structure more compact and resistance to seepages. As the texture becomes more compact the compressive strength, flexural strength &split tensile strength is considerably increased.The laboratory tests are conducted on 43 grade ordinary Portland cement (OPC). The physical tests of the ingredient materials are conducted according to IS specifications .For laboratory tests M30 concrete is adopted. On hardened concrete the strength related test such as Compression, Split tensile and flexural tests on cubes, cylinder and beams are conducted as per IS specifications