Experimental Study on the Mechanical Properties and Cracking Characteristics of Bacterial Concrete

Abstract

Concrete has been used as a construction material for a long period. When the concrete members are exposed to extreme conditions cracks develop. When a crack opens harmful contaminants may enter the concrete matrix. Water may enter through this crack and result in the corrosion of reinforcement bars. Corrosion of the reinforcement bar also results in the formation of cracks. Compressive strength, flexural strength, split tensile strength and permeability are adversely affected by the formation of cracks. Once damaged these structures need to be repaired. Self-healing concrete is an environmentally friendly and cost-effective method for repairing small cracks. An efficient microbial agent for preparing self-healing concrete is the bacillus species. The sample preparation is done by using Bacillus subtilis. The concentration of bacillus opted for the sample preparation is cells per millilitre. The mechanical properties of bacterial concrete are experimentally evaluated and compared with that of conventional concrete. The tension in concrete is usually overlooked while evaluating the strength of reinforced concrete sections because it makes such a small contribution to member strength. Yet it makes a significant contribution to members’ performance under service loads. In this work, tension stiffening of bacterial concrete is experimentally evaluated on concrete prismatic members made of M20 grade concrete reinforced with 8mm and 12mm diameter bars. The direct tension specimen has a cross-sectional dimension of 60 X 60mm and a length of 600mm. The total length of the steel-reinforced specimens, including the bars, is 900 mm. The tension-stiffening properties of bacterial concrete are compared with that of conventional concrete.