Strength Development and Erosive Deterioration of Solidified Soil Exposed to Salty Soil

Abstract

To reveal the impact of erosion environment and age on the strength and deterioration of solidified soil exposed to salty soil, two types of solidified soil, soda residue-ground granulated blast furnace slag-carbide slag solidified soil (S20G10) and cement solidified soil (C10), were eroded by salty soil prepared with kaolin mixed with Na₂SO₄, MgSO₄ or seawater. The unconfined compressive strength tests, X-ray diffraction and scanning electron microscopy analysis were conducted. The results showed that 1% MgSO₄ erosion resulted in the most significant reduction in strength. After 28 days of erosion, the strength was approximately 66% to 68% of the standard curing sample. The strength initially increased and then decreased with the erosion age. Numerous needle-like ettringite or thamuasite were generated in the samples, which led to a loose microstructure and decrease in strength. Sample S20G10 showed stronger erosion resistance than sample C10. The bearing capacity of solidified soil exposed to MgSO₄ erosion exhibited an initial increase followed by a decrease with erosion age. When considering erosion deterioration for 50 years, it was necessary to increase the pile diameter by 1.1 to 1.7 times if the bearing capacity of the mixing pile was equal to the allowable bearing capacity.