Bio-remediation of cracks – a novel technique to self-heal cracks in the concrete

Abstract

A novel technique of self-healing cracks by bacterial species through microbial-induced calcite precipitation (MICP) was developed to counteract the effect of the cracks in concrete structures. This article investigates the influence of two bacterial species, Bacillus subtilis, and Escherichia coli, on the mechanical, durability, and self-healing properties of concrete. The bacterial solutions were cultured in Luria bertani medium to different cell concentrations of 10¹, 10³ and 10⁵ cells/ml. Tests were performed to evaluate the workability, hardened properties such as compressive strength, split tensile strength, flexural strength and durability properties, such as water absorption, acid attack and marine water attack at respective ages. The study concluded that concrete containing bacterial species improves mechanical and durability properties compared to control concrete, and the concrete mixtures with B. subtilis performed better than Escherichia coli. A maximum of 12.8% increase in the strength of the concrete and a 62.1% decrease in water absorption was observed with B. subtilis at 10⁵ cells/ml concentration. SEM analysis performed shows the precipitation of calcite that deposits on the micro-pores and improves the properties of the concrete. Self-healing studies show the deposition of calcite that seals the cracks on the surface of the concrete specimens.

Keywords:

• Bacillus subtilis
• Escherichia coli
• Luria bertani
• microbial induced calcite precipitation
• self-healing

Acknowledgements

The author would like to acknowledge the student P Rajesh, Department of Civil Engineering Kalasalingam Academy of Research and Education for supporting us in the experimental works.

Disclosure statement

The author declares no relevant financial or non-financial competing interests to report.

Data availability statement

The author confirms that the data supporting the findings of this study are available within the article and its Supplementary materials.

Additional information

Funding

This research work does not involve any funding from the external source.