矿物掺合料对低水胶比浆体流变性能的影响机制研究  

Effect of Mineral Admixtures on Rheological Properties of Paste with Low Water-Binder Ratio and Its Mechanism

作　　者：张倩倩 刘建忠 张丽辉 刘加平 ZHANG Qianqian;LIU Jianzhong;ZHANG Lihui;LIU Jiaping(Jiangsu Sobute New Materials Co.Ltd.,Nanjing 211103,China;State Key Laboratory of High Performance Civil Engineering Materials,Nanjing 210008,China;School of Materials Science and Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]江苏苏博特新材料股份有限公司,南京211103 [2]高性能土木工程材料国家重点实验室,南京210008 [3]东南大学材料科学与工程学院,南京210096

出　　处：《材料导报》2020年第22期22054-22057,22086,共5页Materials Reports

基　　金：国家重点研发计划项目(2018YFC0705400)。

摘　　要：本实验研究了硅灰、粉煤灰和磨细矿渣对浆体流变性能的影响,并采用最小需水量法测试浆体中颗粒湿堆积密实度,通过分析颗粒表面的水膜层厚度探讨了掺合料对浆体流变性能的作用机理。研究结果表明:低水胶比水泥浆体表现出典型的剪切增稠特性,掺入硅灰增加了浆体的屈服应力和粘度,浆体由剪切增稠转变为剪切变稀。粉煤灰和磨细矿渣均降低了浆体屈服应力和粘度,但对流体特性无显著影响。水膜层厚度是影响浆体流变性能的关键因素,可反映颗粒堆积和颗粒总比表面的共同作用,水膜层厚度越小,浆体屈服应力和粘度越大。水膜层厚度随硅灰掺量的增加而减小,随粉煤灰和磨细矿粉掺量增加而增大。The effect of silica fume,fly ash and ground slag on rheological properties of cement paste with low water-binder ratio was investigated.In order to study its mechanism,the minimum water demand method was employed to test wet packing density of particles in paste and the water film thickness on the surface of particles.The results show that cement paste with low water-binder ratio showed typical shear-thickening beha-vior.The addition of silica fume increased yield stress and viscosity,decreased the exponent n,and then the paste exhibited a shear-thinning behavior.The addition of fly ash decreased yield stress and viscosity,but had no significant effect on the exponent n.Water film thickness,which could evaluated the combined effects of packing density and solid surface area,was one of the key factors affecting rheological properties of paste,and yield stress and viscosity decreased with the decreasing of water film thickness.Water film thickness decreased with the increasing silica fume content,but increased with the addition of fly ash and ground slag.

关 键 词：水泥浆体 矿物掺合料 流变性能 堆积密实度 水膜层厚度 

分 类 号：TU528[建筑科学—建筑技术科学]