Compression and water retention behavior of saline soil improved by MICP combined with activated carbon.

Saline soil is widely distributed in China and poses significant challenges to engineering construction due to its harmful effects, such as salt heaving, dissolution collapse, and frost heaving. The Microbial-Induced Calcite Precipitation (MICP) method is an emerging environmental-friendly modification that can reduce or eliminate the environmental and engineering hazards of saline soil. To verify the feasibility of the MICP method for improving the properties of saline soil, laboratory tests were conducted to study the effects of salt content, activated carbon content and freeze-thaw cycles on the compression and water retention behavior of MICP modified saline soil. The following conclusions were drawn: calcium carbonate produced from the MICP can cement the soil particles of the modified soil structures, which resists the expansion damage caused by salt frost heaving and reduces soil compressibility. Additionally, calcium carbonate particles can fill pores of the soil structures, which improves the water retention capacity of the modified saline soil. The addition of activated carbon can enhance the MICP reaction leading to further reduction in compressibility and enhancement in water retention capacity of MICP modified saline soil.