Performance of Standard Grade Bacterial Concrete

The objective of the present investigation is to obtain the performance of the concrete by the microbiologically induced special growth/filler. One such thought has lead to thedevelopment of a very special concrete known as Bacterial Concrete where bacteria isinduced in the mortars and concrete to heal up the faults. Researchers with differentbacteria’s proposed different bacterial concrete’s. Here an attempt was made by using thebacteria “Bacillus subtilis”. Calcite formation by Bacillus subtilis is a model laboratorybacterium, which can produce calcite precipitates on suitable media supplemented with acalcium source. Cement mortar cubes with four different cell concentrations were cast and control specimen was also cast. This study showed a significant increase in th compressive strength was observed due to the addition of bacteria for a cell concentration of 105 cells per ml of mixing water. From Scanning Electron Micrography analysis, it is noted that pores were partially filled up by material growth with the addition of the bacteria. Reduction in pore due to such material growth will obviously increase the material strength. Concrete cubes with and without addition of bacteria were cast and it is observed that there is an improvement in the compressive strength for the cubes with the addition of bacteria. Concrete cylinders with and without addition of bacteria were cast and it is observed that there is an improvement in the Split tensile strength for the cylinders with the addition of bacteria. From the durability studies, the percentage weight loss and percentage strength loss with 5% H2SO4 revealed that Bacterial concrete has less weight and strength losses than the conventional concrete and it also revealed that bacterial concrete is more durable in terms of “Acid Durability Factor” and “Acid Attack Factor” than conventional concrete.