Impact of various bacteria on concrete properties: an experimental study

Due to its strength and cost-effectiveness, concrete is the preferred construction material globally. Environment substantially affects system behaviour. Changes in temperature, moisture content and drying shrinkage can cause concrete to fracture. This present research work intends to improve concrete strength and durability by adding Bacillus subtilis, Bacillus cereus and Bacillus cohnii creating “Microbial Concrete.” Different tests have been carried out such as compressive strength, water absorption, UPV, RCPT, sorptivity and microstructural analysis on the concrete samples which further have been compared with test results of controlled concrete samples and also compared with each other after the treatment with three different bacterial solutions at 7 days, 14 days and 28 days curing period respectively. The test findings demonstrated that the capability of Bacillus subtilis of precipitating more calcite crystals within the voids of the concrete samples than other bacterial solutions. A minimum concentration of Bacillus subtilis resulted in maximum concrete strength, reduced water absorption rate, reduced permeability, reduced sorptivity and excellent UPV value. Also, the microstructural analysis proved the same about the bacterial solution used as an admixture in the concrete samples.