34 / 2022-03-14 10:53:54

Self-healing concrete based on microbial mineralization

Concrete; Crack; Self-healing; Microbial mineralization; Engineering application

Self-healing concrete based on microbial mineralization

Chunxiang Qian^1,2,3

1.School of materials science and Engineering, Southeast University, Nanjing, China

2.Research Center for Green Construction Materials &Carbon Utilization, Southeast University, Nanjing, China

3. Key Laboratory of Microbial Bio-mineralization, China Building Industry, Nanjing, China

Abstract: Concrete has low tensile strength and is easy to crack, and the cracks are one of the key factors that reduce the service life of concrete structures. Self-healing concrete is a type of concrete that can actively perceive and intelligently repair cracks, and has attracted much attention from researchers at home and abroad. In the past decade, our team has systematically studied self-healing concrete based on microbial mineralization technology, clarified the physical and chemical environment characteristics and time-varying laws of concrete crack areas, and found the main influencing factors and control methods of the germination and growth characteristics of microbial spores, enzyme catalysis, mineralization and product characteristics. On this basis, a crack repair depth and compaction characterization system and a method for marking mineralization products in the crack area were proposed, which successfully achieved the rapid induction of deposition of highly cementitious biominerals within the crack depth range, breaking through the time and space limitations of conventional microbial mineralization.

In the aspect of engineering advancement of microbial self-healing concrete, a quantitative design method of microbial self-healing concrete was proposed through the theoretical analysis of probability density and large sample capacity test. In the laboratory system, the self-healing performance of microbial self-healing concrete, the reinforcement performance before and after repairing, anti-chloride ion penetration performance, water resistance, etc. were systematically analyzed, and the working performance, mechanical performance and durability of microbial repairing agent were verified. In the end, the project demonstration application of the Mangdao River Ship Lock Expansion Project of the South-to-North Water Diversion Project, the Maqun Station of the Ningju Intercity Railway and the Qilinmen Station was successfully carried out. On the basis of laboratory research and engineering demonstration application, the "Technical specification for application of microbial based self-healing concrete" were compiled.

Keywords：Concrete; Crack; Self-healing; Microbial mineralization; Engineering application