胶凝材料组成对高强混凝土早期温升的影响

Influence of cementitiousmaterial composition on the early temperature rise of high strength concrete

分别在25、50℃条件下测定了水泥、水泥-矿渣、水泥-粉煤灰-硅灰三种不同胶凝材料的水化放热特性,并测定了分别用三种胶凝材料配制的相同强度等级的混凝土的绝热温升。试验结果表明:无论在常温还是高温条件下,水泥-粉煤灰-硅灰体系的水化放热速率始终低于纯水泥体系;水泥-矿渣体系的水化放热速率在水化减速期的后阶段超过纯水泥体系,使其与纯水泥体系的放热量差距缩小;提高水化温度对水泥-矿渣体系的水化促进作用非常明显。混凝土的初期绝热温升与其胶凝材料在常温条件下的水化放热特性相关性强,随着内部温度的增大,绝热温升与其胶凝材料在高温条件下的水化特性具有更好的相关性。

The exothermic properties of cement, cement-ggbs, cement-fly ash-silica fume were determined under the conditions of 25 ℃ and 50 ℃ ,respectively.In the meanwhile,the adiabatic temperature rises of the concretes prepared by the three binders with the same strength grade were determined.The results show that the exothermic rate of cement-fly ash-silica fume is lower than that of pure cement at each period under whether 25 ℃ or 50 ℃ .The exothermic rate of cement-ggbs exceeds that of pure cement at the late deceleration period, which decreases the difference of hydration heat between the two cementitious systems.The influence of increasing hydration temperature on the hydration of cement-ggbs is the most significant.The discipline of the initial adiabatic temperature rises of concretes and theircemen- titious materials exothermic propertiesunder normal temperature conditions have a strong correlation.As the temperature rises inside the concretes, the discipline of the adiabatic temperature rises and theircementitious materials exothermic propertiesunder high temperature conditions have a better correlation.