不同缓凝剂对高贝利特硫铝酸盐水泥性能的影响及机制

Influence and Mechanism of Different Retarders on the Performance of High Belite Sulphoaluminate Cement

以凝结时间和流动度等宏观测试为基础,结合水化热、热分析(TG-DTG)和X射线衍射(XRD)等微观测试,研究了硼酸、柠檬酸和葡萄糖酸钠对高贝利特硫铝酸盐水泥性能的影响以及影响机制.结果表明:3种缓凝剂对高贝利特硫铝酸盐水泥的缓凝作用和流动性均有积极的影响,硼酸主要通过阻碍水泥熟料溶解来延缓砂浆的凝结,柠檬酸和葡萄糖酸钠主要通过对水泥熟料溶出的Ca^2+、Al^3+等离子的络合和吸附作用来阻碍AFt晶体的形成,从而起到对砂浆的缓凝作用;3种缓凝剂通过影响AFt晶体的微观形貌和分布,对水泥石的力学性能产生了不同的影响.

The effect of three different retarders including boric acid, citric acid and sodium gluconate, on the properties of high belite sulphoaluminate cement and its influence mechanism were studied through the macro test of setting time and fluidity, combined with the micro test of hydration heat, thermal analysis(TG-DTG) and X-ray diffraction(XRD). The results show that the three retarders have positive effects on the retarding and fluidity of the sulphoaluminate cement. Boric acid retards the setting of mortar mainly by inhibiting the dissolution of cement clinker, while citric acid and sodium gluconate inhibit the formation of AFt crystal by complexing and adsorbing Ca^2+, Al^3+ ions dissolved from cement clinker. Furthermore, the three retarders have different effects on the mechanical properties of cement stone by affecting the morphology and distribution of AFt crystal.