Study on the Durability of Industrial Waste-MgO Synergistically Cured Silty Sand under Dry and Wet Cycle Conditions

Aiming at the common problems of low utilization of industrial solid waste and insufficient performance of pulverized sandy soil roadbase, this study investigated the effect of dry and wet cycles on the mechanical properties of slag-target slag-MgO synergistically cured pulverized sandy soil. The study investigates the impact of dry and wet cycles on the mechanical properties of cured silt soil using unconfined compressive strength tests, mass loss rate measurements, and microscopic characterization techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). It analyzes the changes in hydration products, the bonding strength between soil particles, and the microstructural variations. The results of the study showed that: As the number of wet and dry cycles increased, the mass loss rate of the specimens varied between 14.95% and 18.88%. The strength exhibited a pattern of rising and then falling, with a peak value of 3.90 MPa. the microstructure analysis showed that, with the increase of the number of cycles, the mineral composition of cured silt loam changed, the quartz diffraction peaks were weakened, and the diffraction peaks of the hydration products (e.g., AFt, M-S-H, C-A-H) were enhanced, forming a more compact structure, and improving the structure of cured silty sand, forming a more compact structure and enhancing the strength of the soil. The hydration products of the specimens with high hardener dosage fill the pores, enhance the particle bonding and show higher compressive strength, while the specimens with low hardener dosage have more pores and lower strength due to incomplete hydration reaction or structural damage. The research results can provide theoretical support for the research and development of environmentally friendly slag - calcium carbide slag - MgO cementitious materials and their application in the field of soil reinforcement, such as curing of silty sand.