不同养护温度下硫铝酸盐水泥的水化特性

Hydration Features of Calcium Sulfoaluminate Cement at Different Curing Temperature

研究了无水石膏掺量不同的硫铝酸盐水泥在5℃、20℃和40℃下的凝结时间、强度发展、干燥收缩率及水化产物等.结果表明:无水石膏虽能促进水化产物钙矾石的生成,但对硫铝酸盐水泥熟料水化的影响效果直接取决于养护温度——5℃下,无水石膏会显著延缓早期水化,使凝结时间大幅延长,早期强度显著降低;而20℃和40℃下作用效果相反,因为石膏的掺入能有效抑制高温下钙矾石向单硫型水化硫铝酸钙的转变,所以40℃下掺加石膏所得硫铝酸盐水泥砂浆的抗压强度较不掺时有不同程度的提升.

A study has been performed on the setting time,compressive strength,drying shrinkage ratio and hydration products of calcium sulfoaluminate(CSA)cements with different amounts of anhydrite at 5℃,20℃and 40℃.Results reveal that the effect on the hydration of calcium sulfoaluminate cement clinker depends directly on the curing temperature,although anhydrite can promote the formation of ettringite.At 5℃,anhydrite dramatically delays the early hydration so that the setting time is greatly extended and the early strength is significantly reduced,which is different from the condition at 20℃and 40℃.Because anhydrite can effectively inhibit the transition from ettringite to monosulfate at high curing temperature,the compressive strength of mortar with CSA cement cured at 40℃is higher than that of CSA clinker.