Ji Guangxiang, Ali Hafiz Asad, Sun Keke, Xuan Dongxing, Peng Xiaoqin, Li Jingjun
Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China.
Materials (Basel). 2023 Mar 27;16(7):2652. doi: 10.3390/ma16072652.
Blends of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement can be used to adjust the properties of cement for specific applications. In this study, CSA cement was used as a shrinkage-compensating admixture to improve the hydration behavior and performance (compressive strength and drying shrinkage) of OPC; the expansion behavior of the blended cement mortar was evaluate based on the saturation index of ettringite. The experimental results showed that incorporating CSA cement resulted in a delayed effect on the hydration of CS, shortened the induction periods of the blended cement and decreased the setting time. The CSA cement also improved the early compressive strength and drying shrinkage of the OPC due to its compact microstructure. The drying shrinkage of the OPC mortar decreased by 27.8% when 6% CSA cement was used, but the formation of microcracks due to expansion could negatively impact its late compressive strength development and associated pore structures of the blends when the replacement content of CSA cement exceeded 6 wt.%. The results relevant to the expansion behavior of the CSA cements could induce crystallization stress, enhancing its resistance against shrinkage cracking.
普通硅酸盐水泥（OPC）与硫铝酸钙（CSA）水泥的混合物可用于针对特定应用调整水泥性能。在本研究中，CSA水泥用作补偿收缩外加剂，以改善OPC的水化行为和性能（抗压强度和干燥收缩）；基于钙矾石的饱和指数评估了混合水泥砂浆的膨胀行为。实验结果表明，掺入CSA水泥对CS的水化产生延迟效应，缩短了混合水泥的诱导期并缩短了凝结时间。由于其致密的微观结构，CSA水泥还提高了OPC的早期抗压强度和干燥收缩。当使用6%的CSA水泥时，OPC砂浆的干燥收缩降低了27.8%，但当CSA水泥的替代量超过6 wt.%时，由于膨胀导致的微裂纹形成可能会对其后期抗压强度发展以及混合物的相关孔隙结构产生负面影响。与CSA水泥膨胀行为相关的结果可能会诱导结晶应力，增强其抗收缩开裂能力。
