Bacillus pasteurii is a soil bacterium. It is a protein based bacterium which secretes urease. Bacteria multiplies in the concrete mixture and forms cementacious material called cacite (binder material like cement). Life span of the bacteria is about 200 years and can survive at a temperature of 120ºC. It has high tolerance level for both temperature and pressure. This process is called MICP (Microbiological Induced Calcite Precipitation).
It has a self-healing property when it is used as admixture. It repair cracks and provide strength to the concrete structure. It fills most of the pores by precipitation of calcite which makes the concrete less porous. By filling voids it increases strength upto 30%. It becomes corrosion resistance to reinforcement by making surface water proof. It also decreases initial and final setting time of cement. It decreases the permeability of concrete by pore filling. It also decreases the cement quantity and increases the durability of structure. For RCC, it prevent corrosion by surface decomposition of CaCO3 by Bacillus pasteurii