Investigation on Self-Healing Concrete Using Bacillus Subtilis Bacteria

Abstract

Cracking is a common occurrence in concrete, primarily attributed to its relatively low tensile strength due to External loads which induce high tensile stresses. Immediate and proper treatment is essential to prevent the expansion of cracks, as their unchecked growth may lead to higher repair costs. Bacterially induced calcium carbonate precipitation emerges as an eco-friendly alternative for crack repair. This technique involves the metabolic activities of specific bacteria in concrete, resulting in microbial mineral precipitation. In this study an attempt has been made to define bacterial concrete and its behavior such as self-healing by minor cracks induced in the samples. Concrete cubes of M20, M25 and M30 have been casted with three dosages of bacterial solution (Bascillus Subtilis) as 60 ml, 75 ml & 90 ml per cube (150 mm size). It has been observed that the compressive strength of bacterial concrete has increased slightly as compared to conventional concrete for each dose. The best performance in compressive strength enhancement has been observed for 75 ml dose and best self-healing has been observed for 90 ml dose of bacterial solution (per cube) in bacterial concrete. Ultrasonic pulse velocity test shows excellent quality for all samples of bacterial concrete.