不同岩性石粉对水泥水化性能的影响

Effect of Different Lithology Stone Powder on Hydration Properties of Cement

为了研究不同岩性机制砂石粉作为辅助胶凝材料对水泥浆体水化产物和微结构的影响,本文借助石粉流动度比和活性指数研究了玄武岩、花岗岩、石灰岩三种不同岩性石粉的活性及其对减水剂吸附性的影响,并通过水化量热、XRD、综合热分析、SEM测试了掺不同岩性石粉水泥浆体的水化热、水化产物和微结构。结果表明:三种岩性石粉对减水剂的吸附性大小顺序为花岗岩石粉>玄武岩石粉>石灰岩石粉;石灰岩石粉的3 d活性指数最高,玄武岩石粉的28 d活性指数最高,而花岗岩石粉的3、28 d活性指数均最低;石灰岩石粉的掺入对水泥早期水化具有促进作用,促使水泥浆体在早期形成了更多的水化产物,并伴有水化半碳铝酸钙的生成;玄武岩石粉具有火山灰反应活性,玄武岩石粉的水泥浆体中后期形成了更多水化产物并降低了Ca(OH)2的含量;花岗岩石粉不具有水化反应活性,花岗岩石粉水泥浆体的水化反应程度最低。

To investigate the impact of different lithology stone powder as supplementary cementitious material on hydration and microstructure of cement paste,the fluidity ratio and activity index of stone powder were used to study the activity of three stone powder with different lithology,namely basalt,granite and limestone and their influence on adsorptivity of water reducer.Besides,the hydration heat,hydration products and microstructure of the cement pastes mixed with different lithology stone powder were tested by hydration calorimetry,X-ray diffraction,comprehensive thermal analysis and scanning electron microscope,respectively.The results show that the order of adsorption capacity of three stone powders to water reducer is granite powder>basalt powder>limestone powder.The 3 d activity index of limestone is the highest,the 28 d activity index of basalt is the highest,while the 3 and 28 d activity indexes of granite are the lowest.The addition of limestone can promote the early hydration of cement,and more hydration products are formed in the paste mixed with limestone in the early stage,accompanied by the formation of hemicarboaluminate.Basalt has pozzolanic reactivity,which promotes the formation of more hydration products and reduces the amount of Ca(OH)2 in the cement paste mixed with basalt in the middle and late stages.Granite has no hydration reaction activity,and the hydration reaction degree of the paste mixed with granite is the lowest.