Experimental studies on mechanical and expansion characteristics of cement-stabilized saline soil reinforced with activated silica fume

In this study, the effect of activated silica fume (ASF) on restraining the expansion of cement stabilized saline soil (C-S) was investigated through stability and durability test. The effects of salt content, silica fume content, erosion conditions and freeze-thaw cycles on the volume, strength and stability of the sample were studied. The results reveal that ASF can inhibit expansion and improve stability, but it was affected by ASF and salt content. At 2% salt content, the expansion rate is reduced by 65.2~83.4%, and the unconfined compressive strength (UCS) and flexural strength (FS) are increased by 2–6 times; at 5% salt content, the expansion rate is reduced by more than 88.5%, and the UCS and FS are increased by 1.6–4.7 times. Salt erosion increased the volume of samples and decreased the strength, which was positively correlated with salt concentration and negatively correlated with the dosage of silica fume. Comparing to the samples without ASF, the volume change of cement-ASF-saline soil is reduced by three times and the strength is increased by eight times after 10 cycles of freeze-thaw. In medium saline soil reinforcement, the low dosage of ASF inhibited expansion efficitivly, but required large dosage in strong saline soil.