Soil strengthening via temperature-optimized MICP within 20 hours: a laboratory investigation

Microbially induced carbonate precipitation (MICP) offers a sustainable ground improvement technique, yet its temperature dependence remains insufficiently understood. Our results show that an optimal temperature window is obtained at approximately 50–55$$^\circ$$C, significantly higher than the conventional mesophilic optimum of 30–40$$^\circ$$C reported in the literature. We report that a high unconfined compressive strength (4.65 MPa) with a corresponding average calcium carbonate content of 11.4% was achieved at 55$$^\circ$$C within a short treatment period of 20 hours, substantially faster than typical MICP treatments. Microstructural and mineralogical analyses confirm that this rapid macroscopic strength increase is attributable to the formation of a well-developed inter-granular calcite matrix within the optimal temperature window, while an excessively high temperature results in poorly cemented skeletons. The findings demonstrate that a controlled elevated temperature environment can be exploited for enhancing time-sensitive ground improvement applications. The revealed temperature sensitivity paves the way to decoupling the complex electro-assisted MICP processes.