掺加煅烧石膏和煅烧明矾石改善水泥较低温度下的早期性能

Improving the Early Strength Properties of Cement at Lower Temperatures by Adding Calcined Gypsum and Calcined Alunite

用煅烧石膏和煅烧明矾石代替天然二水石膏进行了水泥常温和较低温度（２ ～８ ℃） 下的有关物理性能试验，并借助于ＸＲＤ、ＤＴＡ 和ＳＥＭ 测定分析了水化产物相。试验结果表明，煅烧石膏和煅烧明矾石单掺和复合双掺的掺入量为５ ％ 时，水泥的凝结时间明显缩短，３ｄ 耐压强度在各温度下均有显著提高。早期强度提高的主要原因是形成了较多的水化硫铝酸钙及减少了晶体氢氧化钙的含量。

Hydration behavior and related physical properties of cement at lower temperatures (2～8℃) with natural gypsum replaced by calcined gypsum and calcined alunite were studied,and XRD,DTA and SEM measurement analyses were conducted.Experimental results show that,when calcined gypsum and calcined alunite were added by 5% alone or synchronously,the setting time of cement decreases remarkably and 3d compressive strength at different temperatures increases remarkably.The increase of 3d compressive strength is attributed to the increase of AFt and the decrease of Ca(OH) 2 in hardened cement paste.