水化热抑制剂对水泥水化的调控作用

Regulating effect of hydration heat inhibitor on cement hydration process

采用水化热、混凝土绝热温升、混凝土抗压强度、TG-DSC、XRD,分析了水化热抑制剂对水泥水化的调控作用,并采用水泥净浆温升对比了常用缓凝剂与水化热抑制剂的差别。结果表明:水泥净浆温升中,常用缓凝剂仅推迟了温峰时间3~12 h,未明显降低温升,水化热抑制剂推迟温峰时间6 h,降低温升20.5℃;掺入水化热抑制剂,水泥的水化放热速率峰值从0.00259 W/g降至0.00178 W/g,峰时延迟5.7 h;基准、水工混凝土的绝热温升曲线分别在0~1.5 d、0~5 d时间段明显降低,对应的抗压强度分别在0~2 d,0~7 d有不同程度降低,但中后期强度增长均略高于空白试样;TG-DSC、XRD分析表明,水化热抑制剂延缓了水泥0~3 d的水化,对3 d后水化有一定促进作用。

By using hydration heat,adiabatic temperature rise and compressive strength of concrete,TG-DSC and XRD,the regulating effects of hydration heat inhibitor on cement hydration were analyzed.The difference between common retarders and hydration heat inhibitors was compared by the temperature rise of cement paste.The results showed that:in the temperature rise of cement paste,the retarder only delayed the temperature peak time by 3 to 12 hours without effect of reducing temperature rise,however,the hydration heat inhibitor not only delayed the temperature peak time by 6 hours and also reduced the temperature rise by 20.5℃.With the addition of hydration heat inhibitor,the cement hydration's peak of heat release rate significantly decreased from 0.00259 W/g to 0.00178 W/g,delayed the peak time by 5.7 hours.The normal concrete and the hydraulic concrete'sadiabatic temperature rise decreased significantly at 0~1.5 days and 0~5 days respectively,and the corresponding compressive strength decreased in different degree at 0~2 days and 0~7 days respectively,but the concrete's compressive strength growth in the middle and late period was slightly higher than the blank.In TG-DSC and XRD,hydration heat inhibitor delayed the 0~3 day's hydration of cement,but promoted the hydration after the age of 3 days.