Microbial repairing of concrete & its role in CO2 sequestration: a critical review

Abstract

BackgroundBeing the most widely used construction material, concrete health is considered a very important aspect from the structural point of view. Microcracks in concrete cause water and chlorine ions to enter the structure, causing the concrete to degrade and the reinforcement to corrode, posing an unacceptable level of structural risk. Hence repair of these cracks in an eco-friendly and cost-effective way is in the interest of various researchers. Microbially induced calcite precipitation (MICP) is an effective way considered by various researchers to heal those concrete cracks along with an important environmental contribution of CO2 (carbon dioxide) sequestration in the process.Main contentAs the current concentration of CO2 in the earth’s atmosphere is about 412 ppm, it possesses a deadly threat to the environmental issue of global warming. The use of bacteria for MICP can not only be a viable solution to repairing concrete cracks but also can play an important role of CO2 arrestation in carbonate form. This will help in carbon level management to lessen the adverse effects of this greenhouse gas on the atmospheric environment, particularly on the climate. To overcome the insufficiency of studies concentrating on this aspect, this review article focuses on the metabolic pathways and mechanisms of MICP and highlights the value of MICP for CO2 arrestation/sequestration from the atmosphere during the process of self-healing of concrete cracks, which is also the novelty of this work. An overview of recent studies on the implementation of MICP in concrete crack repair is used to discuss and analyse the factors influencing the effectiveness of MICP in the process, including various approaches used for CO2 sequestration. Furthermore, this investigation concentrates on finding the scope of work in the same field for the most effective ways of CO2 sequestration in the process of self-healing cracks of concrete.ConclusionIn a prospective study, MICP can be an effective technology for CO2 sequestration in concrete crack repair, as it can reduce adverse environmental impacts and provide greener environment. This critical study concludes that MICP can bear a significant role in arrestation/sequestration of CO2, under proper atmospheric conditions with a cautious selection of microorganisms and its nutrient for the MICP procedure.Graphical