掺表面改性石英岩粉水泥浆体的强度和自收缩

Strength and Autogenous Shrinkage of Cement Pastes Added with Surface-Modified Quartzite Powder

采用掺入电石渣压蒸和低温煅烧法对石英岩粉进行表面改性,利用X射线衍射、扫描电镜和能谱分析等测试方法对表面改性石英岩粉的矿物组成、表面形貌、元素组成进行表征,测定了掺表面改性石英岩粉水泥浆体的抗压强度和自收缩性能;通过扫描电镜和压汞仪研究了掺表面改性石英岩粉水泥浆体的微观结构.结果表明:压蒸和低温煅烧改性石英岩粉体的表面分别生成了具有胶凝性的托勃莫来石和β-C_2S,增加了石英岩粉表面的胶凝性,改善了石英岩粉与水泥基体的界面结构,从而降低了水泥浆体的孔隙率和自收缩,提高了掺表面改性石英岩粉水泥浆体的早期强度.

The surface of quartzite powder was modified by autoclave method or low temperature calcination method through mixing with carbide slag. The mineral composition, surface profile and element composi- tion of the surface modified quartzite powder were analyzed by X-ray diffraction（XRD） and scanning elec- tron microscope（SEM） combined with energy dispersive spectroscopy（EDS）. The effect of surface modi- fied quartzite powder on compressive strength and autogenous shrinkage of blend cement pastes were in- vestigated. The microstructure of cement pastes was analyzed by using SEM and mercury intrusion poro- simetry（MIP）. The results show that tobermorite and ^-CaS phases are formed on the surface of the modi- fied quartzite powder by autoclave method and low temperature calcinations method. Compounds with hy- draulic activity are formed on the surface of modified quartzite powder, which can improve the interface structure between surface modified quartzite powder and cement paste, and further to enhance early strength and reduce porosity and autogenous shrinkage of cement pastes.