Time-Varying Modeling of Microbial-Induced Calcite Precipitation in Cracked Concrete and Its Inhibitory Effect on Chloride Diffusion

Microbial-induced calcite precipitation (MICP) techniques are promising solutions for repairing cracks in reinforced concrete (RC) structures when exposed to a harsh chloride environment. By means of the lattice network method, this study numerically investigates the entire MICP-induced healing process from crack closure to inhibition of chloride transport of the microbial self-healing concrete by coupling the following two models: (1) the crack self-healing model; and (2) chloride diffusion model. The crack self-healing model provides visualization of the reduction of local crack widths induced by MICP. The chloride concentration distribution is quantitatively reflected through the chloride diffusion model. In addition, an empirical formula is employed to represent the relationship between diffusion coefficients of cracks in the chloride diffusion model and the time-varying crack width obtained from the crack self-healing model. The reduction of crack widths and the distribution of chloride within microbial self-healing concrete are determined through numerical calculations. The simulation reliability is validated based on comparisons with the available literature. Simulation results demonstrate that the MICP-induced crack healing effectively impedes chloride transport.