A Study on Mechanical & Durability Aspects of M-20 grade Bacterial Concrete with Fly Ash

Cracks in the concrete are common which affects the durability of a structure. These cracks should be repaired to increase the strength and durability of the structure, using either epoxy injections or latex treatment. Major problem is that the chemicals used in these treatments cannot reach the deeper portions of the cracks in the structural member and also are expensive. If an effective method and material is found that repairs cracks in concrete automatically (self healing) then the durability of the structure would enormously be increase. Primary motto is to enhance the strength and durability of the structure by treating these cracks with the help of bacteria. The search for new environmental friendly construction materials that improves the strength and durability of concrete structures has developed interest in self healing bacterial concrete with Fly Ash. Bacteria helps in calcite (CaCO3) precipitation through a process called bio mineralization. Bio mineralization is process where common soil bacterium like Sporosarcina Pasteurii, Bacillus subtilis produce calcite. This calcite fills the cracks and compressive strength and durability of concrete is improved. In the present study an attempt is made to understand the effect of bacteria and fly ash on performance of M20 grade concrete. Fly ash content has been varied in 0%, 10%, 20%, and 30% as replacement for cement and bacteria (Sporosarcina Pasteurii) is kept constant at 1x107cells/ml concentration. Cubes and cylinders were cast and strength is monitored for 7, 28, 56 & 90 days. Based on the results, mix with combination of 1x107 cells/ml bacteria and 10% Fly Ash (BCF10) has given optimum performance in terms of compressive strength, split tensile strength, strength loss and weight loss.