Behaviour of Bacterial Concrete

Dr. S. Siddiraju, N. Ganesh Babu

Abstract: Concrete is the most commonly used building material, but the cracks in concrete create problem. Cracks in concrete occur due to various mechanisms such as shrinkage, mechanical compressive and tensile forces. Cracking of the concrete surface may enhance the deterioration of embedded steel bars as ingression rate of corrosive chemicals such as water and chloride ions in to the concrete structure increased. Therefore a novel technique has been developed by using a selective microbial plugging process, in which microbial metabolic activities promote calcium carbonate (calcite) precipitation, this technique is referred as Microbiologically Enhanced Crack Remediation. In this technique urolytic bacteria are used hence the concrete is called Bacterial concrete. The percentages of bacteria selected for the study are 3.5 % and 5 % by weight of cement. In addition, calcium lactate was used at 5 % and 10 % replacement of cement by weight. Varieous tests such as compressive strength, elastic modulus and fracture properties of concrete were analyzed in this study.

Keywords: Bacteria, Cracks, Calcium lactate, alkaline environment, Bacillus pasteurii