Effect of Various Calcite Precipitating Bacteria on Compressive Strength of Concrete: A Comparative Study

The presence of micro pores in concrete makes the concrete weak and less durable, in thisstudy an ecofriendly attempt has been made to minimize these micro pores by calciteprecipitating bacteria i.e. Escherichia Coli, bacillus subtilisand pseudomonas aeruginosawhich produce calcium carbonate when they blend with calcium lactate in presence of waterand air thus filling up the micro pores, thus comparing their effects on compressive strengthof concrete.Various proportions of E. coli, B.subtilisand P. aeruginosa bacterial media wereimpregnated in concrete viz. 10%,20% and 30% replacing the proportion of mixing water,small proportion of fine aggregate was also replaced by calcium lactate and silica gel. It wasobserved that concrete with 10% replacement of P. aeruginosa culture media with mixingwater showed maximum compressive strength with 79.6% increase in the compressivestrength of concrete where as concrete with B.subtilisbacterial media showed 61.1% increasein the compressive strength of concrete and concrete with E.coli bacterial media showed23.5% increase in the compressive strength of the concrete, keeping 10-6 cells/ml the cellconcentration for all bacterial concretes.