Exploring the hydration and shrinking behavior regulated by the superabsorbent polymers in superlight foamed cement made from solid waste-based sulfoaluminate cement

To address the issue of large drying shrinkage and cracking in foamed cement, this paper utilized solid wastebased sulfoaluminate cement as the primary material, blending it with portions of ordinary Portland cement (OPC) to produce ultra-light foamed cement. The study investigated the mechanism by which superabsorbent polymers(SAP) influence the drying shrinkage of foamed cement. The OPC content was varied at 5 wt%, 10 wt%, 15 wt%, and 20 wt%, while SAP content was set at 0.2 wt%, 0.4 wt%, 0.6 wt%, and 0.8 wt%. The compressive strength, dry density, thermal conductivity, volumetric water absorption, and drying shrinkage of the foamed cement were tested, and the impacts of OPC and SAP on compressive strength and drying shrinkage were analyzed. The study found that when the OPC content was 15 wt%, the foamed cement exhibited the best overall performance, with a compressive strength of 0.238 MPa, a dry density of 136 kg/m3 , and a thermal conductivity of 0.046 W/m & sdot;K. This was attributed to the ability of OPC to increase the pH of the cement paste, shorten the setting time, and enhance the foaming efficiency of the foaming agent. When the SAP content was 0.6 wt%, reducing the drying shrinkage rate by 64.37 %. This was attributed to the ability of SAP to rapidly absorb water during the mixing of cement, storing it within their molecular structure. During the drying phase of the cement, the water was released gradually, facilitating the hydration process and reducing the drying shrinkage. These findings demonstrate the critical role of SAP in mitigating the drying shrinkage of foamed cement.