Influence mechanism of supersulfated cement on the rheological behavior and mechanical properties of flowable solidified soil with construction waste soil

To improve the resource utilization of construction waste soil, supersulfated cement (SSC) was used as the main curing agent to prepare flowable solidified soil with construction waste soil. The effect of the water-solid ratio (W/S) and alkaline component (AC) content on the rheological behavior and mechanical properties of the solidified soil was investigated. In addition, its engineering applicability was further verified. The results showed that an increase in the W/S caused a certain shear-thinning phenomenon in the solidified soil. The increase in the AC content could improve the yield stress and plastic viscosity, optimizing the rheological characteristics of the fresh solidified soil. During hardening, higher W/S had a negative effect on the formation of hydration products, resulting in a loose microstructure, weakening the compressive strength and deformation resistance of solidified soil. In comparison, the increase in the AC content improved the alkaline environment of the SSC system, which promoted the formation of hydration products, enhancing the compactness of the solidified soil structure and refining the pore structure. When the W/S was 0.5 and the AC content was 7%, the solidified soil showed favorable rheological and mechanical properties. Its yield stress and plastic viscosity were 3.75 Pa and 0.088 Pa·s, respectively. After 28 d, its strength was 2.18 MPa, and the shrinkage degree only changed by 0.604%. Field operation further demonstrated that the solidified soil could reach a self-leveling effect, and it had favorable strength and slight shrinkage.