Study on Development of Strength Properties of Bio-concrete

Abstract

The objective of this research is to identify a new calcite-precipitating bacteria and trying to improve the strength parameters of concrete. In concrete, cracks are the most vulnerable thing through which water, minerals, and other chemicals will ingress and contacts with reinforcement of concrete and corrosion of reinforcement and degradation of concrete will happen. Overall, the durability is greatly affected due to cracks and these cracks may be micro cracks which are impossible to identify and to assess the locations of these cracks in concrete. Inspection, maintenance, and repair of cracks will be difficult for large-scale infrastructure and most of the repair techniques are chemical based, expensive, and repair techniques can be used for large size cracks but not for micro cracks In order to increase the durability of concrete against these commonly observed cracks in concrete structures, autogenous pore refinement method can be adopted. By using the principle of biomineralization, bacteria forms the calcium precipitations which is usually called microbial-induced calcite precipitation (MIC). In the present work, a different bacterial colony is chosen to see that more improvement in terms of healing capacity of concrete can be achieved compared to Bacillus family, and the bacteria were identified such that which will grow in the high alkaline media, since concrete is highly alkaline material. Bacteria are cultured in the controlled medium to get the desired concentrations of cells, and it is observed that the compressive strength of concrete is improved more than 36% and there is an improvement in other strength parameters also. And also, it is noted that there will be an effect of cell concentration on the strength development. SEM and EDAX analysis reveals the deposition of calcium carbonate.