Effect of Bacillus Cohnii Bacteria on the Properties of Concrete

Abstract

Concrete plays an important role in this era of rapid urbanization. But concrete is quite prone to crack formation, which affects its durability. If immediate precaution is not taken then cracks tend to expand further and require costly repair. Due to the cracks, an easy path is developed in the structure, through which water, oxygen and carbon dioxide, etc. from air penetrates into the concrete which leads to the decrement in durability of concrete. To overcome this disadvantage, various crack healing techniques have come into limelight; one of them is self-healing bacterial concrete. This paper is aimed at finding out the influence of Bacillus Cohnii bacterium on the properties of concrete. Bacterial cell count, i.e. colony-forming unit (CFU) of 105 and 1010 cells/ml were selected for the present work. Then 103 and 108 cells/cm3 bacterial concentrations have been added to concrete for 105 and 1010 cells/ml, respectively. Specimens were tested after different intervals of curing period. When compared to control mix (without the addition of bacteria), it is noticed that concrete with Bacillus Cohnii bacteria shows increment in compressive, flexural and split tensile strength in all curing periods for both cell concentrations 103 and 108 cells/cm3. The highest strength is achieved when 103 cells/cm3 bacterial concentration have been added to concrete for 105 cells/ml.