关键词: 盐渍土, 固化剂, 响应面法, 力学性能, 耐久性, 微观结构

Abstract: The use of mineral powder to reinforce saline soil effectively enhances the strength of saline soil, and reduces the solubility of saline soil foundations. However, the stability of mineral powder under normal temperature conditions is consistent, and its potential reactivity needs to be activated. Addressing this issue, mineral powder was used as a precursor, and the effect of different proportion of desulfurization gypsum-sodium hydroxide-carbide slag (DG-NaOH-CS, DNC) curing agents on the mechanical properties, durability and micro-mechanisms of mineral powder composite solidified saline soil was investigated. The results show that the optimal mix proportion of desulfurization gypsum, sodium hydroxide, and carbide slag is 6.03∶0.63∶4.24 (mass ratio). Based on this optimal mix proportion, the 28 d unconfined compressive strength mean value of DNC-modified soil is 14.16 MPa, with the response surface model predicted value of 14.08 MPa, indicating good correlation between predicted and experimental values. Compared to the same proportion of cement solidified soil, DNC-modified soil exhibits better compressive strength, resistance to freeze-thaw cycles and resistance to wet-dry cycles. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis shows that the DNC curing agent produces a large amount of hydrated calcium silicate (C-S-H), hydrated calcium aluminate (C-A-H), and ettringite (AFt) cementitious materials within the specimen, filling the internal pores of the soil and thereby further enhancing the strength of solidified soil.

Key words: saline soil, curing agent, response surface method, mechanical property, durability, microstructure