Strength Behavior of Temperature-Dependent MICP-Treated Soil

Microbially induced carbonate precipitation (MICP) is a novel soil-strengthening technique that involves a biogeochemical process. Temperature plays a crucial role in influencing the biological and chemical processes involved in the formation of carbonate precipitates, which in turn affect the mechanical properties of the treated soil. The aim of this study was to investigate the impact of temperature on the cementing structure of MICP-treated soils and its subsequent effects on their strength parameters. The results revealed that temperature considerably affected the content, size, and distribution of CaCO3 crystals produced, resulting in variations in the friction angle, cohesion, stiffness, peak strength, residual strength, and dilation of the MICP-treated soil samples. Lower strength enhancement was observed when fewer and smaller carbonate crystals were produced at 4°C and 50°C. In contrast, higher numbers of larger crystal clusters were produced at 20°C and 35°C, which effectively bonded the soil particles. Increasing the number of bacterial injections at 50°C promoted the formation of larger crystals and enhanced strength effectively. This study highlights the temperature effects on calcium carbonate growth in biocemented soils, which is a critical step in determining the field-scale application of this innovative soil stabilization technique.