Study on the Mechanical Properties of Steel Slag Cement–Solidified Silt Soil and the Law of Chloride Ion Transport under Different Erosion Times

Abstract

To study the influence of chloride erosion on the mechanical properties of steel slag cement–solidified silt soil and the law of chloride ion migration, indoor tests were carried out on the physical and mechanical properties and microstructure of steel slag cement–solidified silt soil under chloride erosion, through unconfined compressive strength tests and chloride ion concentration measurement tests. The macroscopic physical and mechanical properties, microstructure changes, and internal chloride ion migration of solidified soil eroded by chlorine salt and solidified using steel slag cement under different conditions were studied using SEM tests. The test results show that with the increase of erosion time, the mass change rate of the steel slag cement soil sample is significantly higher than that of cement soil under the erosion of chlorine salt. The maximum mass change rate is 1.78 times more than that of cement soil, and the maximum difference of water content can reach 9.17% and 8.54%. With the increase of erosion time, the unconfined compressive strength of specimens cured for 7 days showed an overall growth trend; and the broken line of unconfined compressive strength of specimens cured for 28 days showed first increasing and then decreasing. The unconfined compressive strength of the cement soil sample is significantly higher than that of the steel slag cement soil; and its maximum strength is 2.34 times that of steel slag cement soil. With the increase in erosion time, the internal chloride ion concentration first increases and then tends to be stable. The chloride ion corrosion resistance of the cement soil sample is better than that of the steel slag cement soil sample. Compared with the maximum chloride ion concentration, the steel slag cement soil sample is 1.52 times higher than that of cement soil. Microscopically, SEM test results show that with the increase of chloride erosion time, the internal structure arrangement of the cement soil samples becomes relatively loose, which can seriously damage the internal structure of samples and reduce their bearing capacity.