Demonstration application of microbial self-healing concrete in sidewall of underground engineering: A case study

There are many laboratory researches for microbial self-healing concrete (MSC) but few engineering applications. Demonstration application is an essential link from laboratory to practical engineering. This paper describes a demonstration application case of MSC on the sidewall of an underground engineering, aiming to provide practical experience for the large-scale application of MSC. Firstly, microbial healing agent (MHA) with core-shell structure produced using automatic equipment, and laboratory tests were carried out to evaluate the effects of MHA on concrete performance. Then, the feeding method of MHA in concrete mixing station was studied. Finally, the MSC's application effect were studied through embedded sensor and field monitoring. Results show that MHA has no negative effect on concrete properties and does not affect engineering use. Using an external cylinder to deliver MHA can ensure the feeding effect and safe production. Compared with ordinary sidewall, MHA can effectively heal cracks and reduce the number of cracks and the average length, width, and depth. This paper can provide a good demonstration for the popularization and application of MSC and a new technical scheme for the prevention and treatment of sidewall cracks in underground engineering.