微硅粉的物化特性及对混凝土孔结构的影响  

Physicochemical properties of silica fume and its effect to pore-structures of concrete

作　　者：万惠文[1] 陈超[1] 吴有武[1] 韦鹏亮[1] 高志飞[1] 

机构地区：[1]武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉430070

出　　处：《混凝土》2013年第12期77-81,共5页Concrete

基　　金：大宗工业固废处理与资源化技术及示范(第二批)--"863"计划项目(2012AA06A112)

摘　　要：研究了微硅粉的BET氮吸附特性、胶凝特性、水化机理,以及作为矿物掺合料对混凝土孔结构的影响。BET氮吸附测试显示微硅粉为两端开口管状介孔结构,平均孔径7.78 nm,比表面积36.52 m2/g;微硅粉在水泥胶砂中掺量以5%为宜,在混凝土中掺量为10%时,制备的混凝土强度可达95 MPa以上。XRD表明微硅粉与水泥水化生成的Ca(OH)2发生二次火山灰反应可以加快水化速率、明显提高了混凝土强度;MIP分析结果表明,微硅粉可以改善混凝土内部孔结构:减少有害孔、降低孔隙率,平均孔径由20.0 nm减小至13.8 nm,孔隙率从7.74%降低至4.89%。The BET nitrogen adsorption characteristics, gelling properties, hydration mechanism of silica fume would be studied in this article, and the effect to pore-structures of concrete would be researched when silica fume was used as mineral admixture.BET nitrogen ad- sorption test shows that silica fume has tubular mesoporous structure which both ends are opening,its average pore size is 7.78 nm, specif- ic surface area is 36.52 m2/g;the perfect proportion of silica fume in cement mortar is 5% ,and 10% in concrete ,the strength of concrete could reach 95 MPa.XRD show that silica fume accelerate hydration rate, improve strength by reacting with Ca（OH）2 which generated in cement hydration;MIP test show that silica finne can improve pore structure of concrete by reducing the harmful holes and the porosity, the average pore diameter decreased fi＇om 20.0 nm to 13.8 nm, the porosity decreased from 7.74% to 4.89% in this experiment.

关 键 词：微硅粉 BET氮吸附 MIP 火山灰反应 

分 类 号：TU528.041[建筑科学—建筑技术科学]