蒸汽养护对组成不同水泥水化特性影响

Effect of steam curing on hydration characteristic of cement with different compositions

研究了蒸汽养护和标准养护条件下混合材掺量不同的水泥力学性能差异,并利用XRD、SEM、DSC等测试方法对组分不同水泥水化产物及水化特性等进行对比分析。结果表明,与20℃标准养护相比,85℃常压蒸养下水泥水化产物基本相同,且水化产物数量远高于前者,并有钙矾石(AFt)稳定存在;混合材掺量适宜的水泥样品中有亚稳态水化硅酸钙(C_9S_6H_(18))的形成,这可能是蒸养强度差异的主要原因之一。混合材掺量不同,水化产物形貌也存在明显差异。混合材掺量高达50%时,水化产物形成数量明显减少,水泥石结构疏松,蒸养强度显著降低。混合材中硅灰的掺入,有利于细化水泥石结构,促进水泥石蒸养强度的发展。

Mechanics performance difference of cement with different dosage admixture that under standard curing condition and steam curing condition were studied. The hydrate production and hydration characteristic of cement with different compositions were analyzed by XRD, SEM and DSC. The results showed that the hydrate production of cement under 85 ℃ steam curing condition were almost the same as that of cement under 20 ℃ standard curing condition, its hydrate production number were outclass that of cement under 20 ℃ standard curing condition, and AFt exist stability. The C9S6H18 has formed in cement with defined amount admixture, which was one of the prime reasons of steamed strength difference. There existed obviously different alterations of morphology of hydrated products among the cement with different dosage admixture. When the admixture content reach up to 50%, the hydrate production number would obviously decrease, structure of cement stone would loose, and the steam curing strength would obviously decrease. The addition of silica fume could refine structure of cement stone and increase steam curing strength.