Simulation of bacterial-based self-healing concrete: Reactive-transport modelling and semi-implicit finite difference implementation

Abstract

Self-healing concrete has emerged as a sustainable and cost-effective strategy to reduce maintenance demands, with microbially induced calcium carbonate precipitation (MICP) standing out as one of its most efficient and reliable healing mechanisms. This study presents a numerical model for simulating the MICP healing process in concrete cracks. The model explicitly describes bacterial growth, decay, attachment, and encapsulation through simplified kinetic equations, while incorporating temperature effects on bacterial activity, nutrient consumption, and urea hydrolysis. The reduction in crack permeability is captured by extending the classical parallel-plate flow formulation to account for calcium carbonate deposition. To ensure numerical stability and efficiency, a semi-implicit finite difference algorithm is developed, which explicitly evaluates nonlinear reaction terms while implicitly solving diffusion-advection transport equations. The model is verified against analytical solutions and validated using experimental data. Further simulations investigate capsule- and vascular-based healing strategies. Results demonstrate that the proposed model accurately reproduces the coupled biochemical-transport processes and serves as a reliable and efficient predictive tool for assessing MICP-induced crack healing in concrete.