The paper aims at study the setting time and mechanical properties of portland cement-sulphoaluminate cement composite system. Effect of different addition quantity of the Portland cement and mineral admixture on setting time and strength of portland-Sulphoaluminate composite cement were tested. The mineral composition and microstructure were analyzed by XRD and SEM.The results showed that the setting time of portland cement-sulphoaluminate cement decreased first and then increased with the increase of portland cement content, and then decreased with the increase of the amount of the admixture. The strength of portland cement-sulfur cement decreased first and then increased with the increase of portland cement. When the dosage of portland cementwas 10％, the 3 d compressive strength decreased by 10. 67％. The 3 d compressive strength decreased with the increase of mineral admixture. When the amount of mineral admixture was 40％the 3 d compressive strength of mineral powder and fly ash respectively decreased by 44. 5 ％ and47. 9 ％. The two kinds of cement mixing will shorten the setting time and reduce the strength, reduce the hydration products and loosen the structure. The addition of mineral powder and fly ash prolongs the setting time, reduces the strength and hydration products.%目的 研究硅酸盐水泥-硫铝酸盐水泥复掺后的凝结时间及力学性能.方法分别测试不同硅酸盐水泥、矿物掺合料掺量下硅酸盐水泥-硫铝酸盐水泥复合体系的凝结时间及胶砂强度, 并利用X射线衍射仪和扫描电子显微镜进行矿物组成和结构分析.结果 硅酸盐水泥-硫铝酸盐水泥复合体系的凝结时间随硅酸盐水泥掺量的增大先减小再增大, 随掺合料掺量的增大先减小再增大.硅酸盐水泥-硫铝酸盐水泥复合体系的强度随着硅酸盐水泥的增加先减小后增大, 硅酸盐水泥掺量为10％时, 3d抗压强度减小10.67％;随着掺合料的增大而降低, 掺合料掺量为40％时, 矿粉、粉煤灰3 d抗压强度分别减小44.5％和47.9％.结论 两种水泥复掺会缩短凝结时间, 降低强度, 水化产物减少, 结构疏松;粉煤灰和矿粉的掺入会延长凝结时间, 减小强度, 水化产物减少.
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