Effect of bacteria on strength and porosity of M-sand based pumpable concrete

Abstract

This paper presents the results of experimental investigation which was carried out to evaluate the effect of bacteria on the compressive strength, porosity of M-sand concrete. The river sand was replaced by M-sand and M20 and M30grade pumpable concreteswere designed for investigation purpose. The w/c ratio of the concrete was selected as 0.45 and 0.4 respectively. Bacillus subtilis bacteria was included at a concentration of 30x105 cells/mL of water. The compressive strength, water absorption and porosity of concrete were determined after the curing periodof 3, 7, 28 and 90 days. Results were indicated that the substitution of M-sand instead of river sand was reduced the compressive strength up to 20% when compared with river sand based control concrete. The porosity and water absorptionbehaviour of M-sand concrete were observed in higher order than that of control concrete. On the addition of bacteria, 37%-45% reduction in water absorption and porosity level of bacterial M-sand concrete was achieveddue to the self-healing of micro crack in the concrete.