高贝利特硫铝酸盐水泥改性白水泥的物理力学性能与水化作用

白色硅酸盐水泥(白水泥)具有较好的白度,是一种具有装饰效果的胶凝材料。针对该种水泥凝结时间长、早期强度发展慢及收缩变形较大等问题,采用高贝利特硫铝酸盐水泥对白水泥进行改性,系统研究了掺入10%~30%(质量分数)的高贝利特硫铝酸盐水泥对白水泥凝结时间、胶砂强度和自由膨胀率的影响。使用水化微量热仪、XRD、TGA、SEM等方法对复合胶凝体系水化过程、水化产物和微观形貌进行分析。结果表明:高贝利特硫铝酸盐水泥增大了白水泥水化放热率,显著缩短了白水泥的凝结时间;改性后的白水泥水化产物生成了大量的AFt,穿插生长在C-S-H凝胶中,消耗掉了部分Ca(OH)₂,使结构更加致密,强度更高,膨胀性能更好。

Physical and Mechanical Properties and Hydration of High Belite Sulphoaluminate Cement Modified White Cement

White Portland cement (white cement) has good whiteness and it is a cementing material with decorative effects. Aiming at the problems of long setting time, slow early strength development and large shrinkage deformation of this kind of cement, the high belite sulphoaluminate cement was used to modify the white cement. The effect of high belite sulphoaluminate cement mixed with 10% to 30% (mass fraction) on the setting time, mortar strength and free expansion rate of white cement was systematically studied. Hydration microcalorimeter, XRD, TGA, SEM, and other methods were used to analyze the hydration process, hydration products and microscopic morphology of the composite cementitious system. The results show that high belite sulphoaluminate cement increases the hydration heat release rate of white cement, and significantly shortens the setting time of white cement. The modified white cement hydration product generates a large amount of AFt, which grows interspersedly in the C-S-H gel, consuming part of the Ca(OH)₂, making the structure more compact, strength higher, and expansion performance better.