本文研究了不同拌和水以及海水拌和时粉煤灰和硅灰掺量对硫铝酸盐水泥(SAC)砂浆力学性能和表观孔隙率以及净浆凝结时间、化学收缩、孔溶液pH值和氯离子结合能力等的影响, 并通过XRD、SEM和EDS分析水泥水化产物和微观结构。结果表明, 海水能加快SAC早期水化并提高其早期强度, 但后期强度和淡水拌和时无明显差别。粉煤灰和硅灰均会延长SAC凝结时间, 对早期抗压强度不利, 而掺加质量分数为5.0%和7.5%的硅灰能提高SAC砂浆28 d抗压强度。硅灰掺量增加时会提高用水量和表观孔隙率, 降低流动性, 使水泥化学收缩增大, 降低净浆pH值且减少氯离子结合量; 粉煤灰能够提高砂浆流动性, 减少水泥化学收缩, 但掺量越大对SAC砂浆抗压强度和抗折强度越不利, 掺质量分数为10%的粉煤灰可小幅提高氯离子结合量且减小表观孔隙率。

In this paper, the effects of sea water and mineral admixture on the mechanical properties and apparent porosity of sulphoaluminate cement (SAC) mortar, the properties such as setting time, chemical shrinkage, pH value of pore solution and chloride ion binding capacity of paste were studied. Furthermore, the hydration products and the microstructure of SAC were analyzed by XRD, SEM and EDS. The results show that sea water accelerates the early hydration of SAC and improves its early strength, while there is no significant difference in the long-term strength of cement mortar between sea water and fresh water. Both fly ash and silica fume prolong the setting time of SAC, which is disadvantageous to the early compressive strength. 28 d compressive strength of SAC mortar improves with the silica fume mass fraction of 5.0% and 7.5%. As the silica fume content increases, the water consumption, chemical shrinkage and apparent porosity of SAC increase. However, the fluidity, the pH value and the chloride ion binding amount of cement paste reduce with the increase of silica fume content. Meanwhile, Fly ash improves the fluidity of mortar and reduces the chemical shrinkage of cement paste. But the adverse effect on the compressive strength and flexural strength of SAC mortar is more obvious with the increase of fly ash content. When 10% (mass fraction) fly ash is added, the chloride ion binding amount increases and the apparent porosity reduces slightly.