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采用初、终凝时间,抗压强度试验,对不同磷石膏掺量下经550℃热处理得到的水泥浆脱水相的再水化硬化性能进行了研究。采用XRD、SEM等测试手段测定了矿物组成及微观结构。结果表明:磷石膏的加入使得浆体凝结时间延长,显著地改善了其工作性能;同时,随着磷石膏掺量的增加,抗压强度呈上升趋势,并在掺量为8%时达到最大值。微观测试表明:磷石膏-水泥浆脱水相复合胶凝材料体系的主要水化产物是钙矾石、CSH凝胶等,且钙钒石和CSH凝胶相互交织形成密实的网状结构。
The initial and final setting time and compressive strength test were used to study the rehydration and hardening properties of dehydrated cement slurry obtained by heat treatment at 550 ℃ with different content of phosphogypsum. The composition and microstructure of the minerals were determined by XRD, SEM and other testing methods. The results show that the addition of phosphogypsum prolongs the setting time of the slurry and significantly improves its working performance. Meanwhile, the compressive strength of phosphogypsum increases with the increase of phosphogypsum, and reaches its maximum at 8% value. The microscopic tests show that the main hydration products of phosphogypsum-cement dewatering phase composite cementitious material system are ettringite, CSH gel, etc., and the ettringite and CSH gel are intertwined to form a dense network structure.