Application of microbial self-healing concrete: Case study

It has become a green and environmentally friendly method to repair concrete cracks by microbial induced calcium carbonate precipitation (MICP). However, most studies were concentrated in the laboratory, and practical engineering applications are rarely conducted. Hence, in order to promote the application of microbial self-healing concrete, the researches of microbial healing agents and self-healing concrete were carried out. Then, the construction technologies of microbial self-healing concrete were explored through engineering practice. Results showed that the spray-dried fermented bacteria method has great potential for the production of powder-based and capsule-based microbial healing agents of concrete. Compared with the liquid-based healing agents, it was more convenient in terms of production, transportation, storage, and use. For the existing concrete production line, the feeding of microbial healing agents draws on the production experience of fiber concrete. To guarantee the self-healing effects, necessary curing measures should be taken to keep the cracks wet and supply nutrients for bacteria. The degree of self-healing can be evaluated by observing the changes in ultrasonic wave speed and waveform, which is an effective non-destructive method to quantitatively characterize the self-healing efficiency in construction sites. The production and construction experience provided a good reference for the commercialization of microbial self-healing concrete.