Microbial self-healing in concrete: A comprehensive exploration of bacterial viability, implementation techniques, and mechanical properties

Abstract

Cracks in concrete structures can significantly decrease their lifespan by exposing reinforcement to outside environment, leading to concrete degradation. To address this issue, self-healing techniques have been developed, including biomineralization-based-self healing, where bacteria are employed to initiate microbially induced calcium precipitate (MICP), promoting the healing of cracks. This article explores the extreme environmental conditions including pH and temperature which can reduce sustainability and self-healing potential of bacteria. Furthermore, it explores the implementation techniques of using bacteria in concrete aimed at mitigating the adverse effects of the concrete environment on bacteria, thereby enhancing their self-healing capabilities. Notably, studies have found that the mechanical strength of concrete can be increased at cell concentrations of 105 to 108 cells/ml. Based on this review, it is found that the self-healing of concrete depends on factors such as environmental conditions of pH and temperature, as well as the implementation methods of bacteria in concrete. Moreover, there exists a direct correlation between bacterial cell concentration and alterations in the mechanical properties of concrete. The incorporation of bacteria in concrete leads to increment in strength properties, with strength enhancement of up to 42.8 %. Understanding the interplay between environmental factors and bacterial sustainability is crucial in optimizing biomineralization-based self-healing and enhancing the durability of concrete infrastructure.

Keywords

• Bacillus bacteria
• Concrete properties
• Encapsulation
• Microbially induced calcium precipitate
• pH
• Temperature