Enhancement on mechanical parameters of concrete by Application of bacillus megaterium bacteria

Abstract

This paper presents experimental results of self-healing process of concrete and effects on mechanical properties of concrete. Essentially, the self-repair of concrete occurs when cracks close due to the rehydration of unhydrated or inadequately hydrated cement particles within damaged areas. Bacterial concrete facilitates crack healing by converting calcium lactate to calcium carbonate through microbiological processes, leading to the cessation of crack propagation. Bacillus genus demonstrates impressive efficacy in diverse conditions for concrete reinforcement. Concrete vulnerabilities to attacks are inherent and cannot be entirely prevented. Water infiltration through these cracks initiates corrosion, significantly reducing the lifespan of concrete. Hence, there was a pressing need to develop and activate biomaterials for a self-repairing technique that could effectively address cracks and fissures in concrete. Bio-concrete emerges as a promising solution for enhancing concrete durability. This approach is highly desirable as it promotes eco-friendly crack remediation, employing Bacillus megaterium to induce artificial crack healing in cement concrete. Specimens were cast and subjected to mechanical strength and water absorption tests after 7 and 28 days of curing. Results show a notable improvement in compressive and flexural strengths by 12.91% and 9.02% respectively, compared to standard M25 grade concrete mix, after 28 days of curing. Additionally, bacterial concrete exhibits lower water absorption values than standard concrete mix, attributed to crack filling via calcite precipitation facilitated by Bacillus megaterium bacteria.Consequently, Bacillus megaterium, belonging to the Bacillus family, proves to be an effective agent for enhancing mechanical strength by reducing voids in concrete. Key Word: Bacillus Megaterium, compressive strength, bio-concrete, water permeability, activated biomaterial, flexural strength, water absorption.