Bacteria-Based Concrete Crack Healing: A Review of Crack Healing Effecting Factors and Size

It is well-known how water contaminants affect the durability of concrete and cracked concrete are even more exposed to these contaminants. A technique to achieve self-initiating self-healing of cracked concrete is the incorporation of microbial calcite disposition. This technique makes use of the organic activities of bacteria in reaction with additional minerals and compounds to form a sealing compound, commonly calcite. This research serves as a review of previous and on-going research on the topic of self-healing concrete using bacteria and how it affects and is affected by factors such as the concrete mix proportions and how calcium salts, bacterial nutrients, urea, yeast extract, sugars, sodium, proteins, buffer solutions, humidity and concrete surface treatment affect properties such as setting, hardening and carbonation in addition to reviewing the methodologies used to deal with relatively large cracks via sporulation and vascular networks. The review shows the significance of Ph and porosity of concrete on the survivability of the bacterial cells in addition to the necessity of encapsulation of said cells. Calcium lactate, sodium, proteins and trisaminomethane proved to all aid bacterial growth and the hydration process. Optimum temperature and humidity for self-healing were also pointed out in addition to the effects of self-healing on the water absorption and rates of carbonation during the surface treatment process. Past research on self-healing concrete using bacteria has been reviewed within this paper in relation to the complications that may occur during the setting, hardening, and carbonation of concrete in addition to addressing the issue of healing large cracks. © 2022 American Institute of Physics Inc.. All rights reserved.