Proper utilization of lower cost waste materials and industrial by-products for subgrade filling soil stabilization is an avenue of resource conservation and environmental protection. In this study, red Pisha sandstone (RPS) and carbide slag (CS) were selected to stabilize silty clay. The improvement effects of RPS–CS-stabilized soil with different admixture contents were evaluated through strength and durability tests. In addition, the mechanism of the improvement was investigated. The results indicate that the triaxial compressive strength of silty clay stabilized with 15 wt.% RPS and 15 wt.% CS was 81–136% times that of the unstabilized silty clay. After 20 freeze–thaw cycles, the strength loss ratio was 0.4–4.7% and the compression coefficient increased from 0.053 to 0.069 MPa⁻¹. More sand-size particles are beneficial to the adequate agglomeration and hydration reactions of RPS and CS. Large amounts of small rounded and plate-like calcium silicate hydrates (C–S–H gels) filled the soil’s pores and the number of isolated pore fractures in the samples decreased, which was responsible for the excellent mechanical properties of the RPS–CS-stabilized silty clay. The results of this study provide a reference for the utilization of red Pisha sandstone and carbide slag as sustainable stabilizers in embankment applications in seasonally frozen regions.

合理利用成本较低的废料和工业副产品进行路基填土加固是节约资源和保护环境的一条途径。本研究选用红皮沙砂岩 (RPS) 和电石渣 (CS) 来稳定粉质粘土。通过强度和耐久性试验评估了不同掺合剂含量的 RPS-CS 稳定土的改良效果。此外，研究了改进的机制。结果表明，用 15 wt.% RPS 和 15 wt.% CS 稳定的粉质粘土的三轴抗压强度是不稳定粉质粘土的 81-136%。经过20次冻融循环后，强度损失率为0.4-4.7%，压缩系数从0.053增加到0.069 MPa ^-1. 更多的砂粒大小有利于RPS和CS的充分团聚和水化反应。大量小的圆形和板状硅酸钙水合物（C-S-H凝胶）充满了土壤的孔隙，样品中孤立孔隙裂缝的数量减少，这是RPS-CS-具有优异力学性能的原因。稳定的粉质粘土。本研究结果为红皮沙砂岩和电石渣作为可持续稳定剂在季节性冰冻地区路堤应用中的利用提供了参考。