目的 降低原状工业硅粉颗粒的团聚现象和聚集效应，提高其分散性，改善掺硅粉水泥基材料的力学及界面过渡区性能。方法 采用表面化学修饰和机械分散两种改性方法，对硅粉进行表面改性。利用表面电位测试、紫外光谱分析、激光粒度分析、扫描电镜测试等试验手段，评价了改性前后硅粉颗粒的表面电位和减水剂分子吸附量、颗粒粒度分布，以及硅粉颗粒和硬化硅粉-水泥净浆的微观形貌。采用棱柱体试件，研究了改性硅粉对水泥-硅粉净浆抗折与抗压强度的影响。结果 用氨丙基三乙氧基硅烷及磁力搅拌工艺对原状工业硅粉进行表面改性后，硅粉表面电位由?21 mV变为+3 mV，高性能聚羧酸减水剂吸附量提高了60%，硅粉中纳米级微细颗粒数量显著增加，大颗粒团聚现象明显降低，硅粉颗粒的分散性明显改善；改性硅粉使水泥-硅粉净浆的力学性能提高了11%~24%。结论 采用氨基硅烷和磁力搅拌工艺对原状硅粉表面改性后，硅粉表面的电位由负值变为正值，减水剂吸附量显著增大，颗粒团聚性降低，纳米级颗粒数量增多，在水泥中分散性改善，水泥-硅粉水化产物的界面过渡区性能改善，掺硅粉水泥浆体的力学性能明显提高。

The work aims to improve mechanical and interfacial transition zone (ITZ) properties of silica fume-doped cementitious materials by reducing agglomeration and aggregation of silica fume particles and enhancing dispersibility. The surface of silica fume was modified in the methods of chemistry graft reaction and mechanical dispersion. Then surface potential, superplasticizer adsorption capacity and particle size distribution, and microstructure of the silica fume particles and hardened silica fume-based cement paste were characterized in such test methods as surface potential measurement, ultraviolet spectrum analysis, laser particle size analysis and scanning electron microscope. Prism specimens were employed to evaluate the effects of modified silica fume on flexural strength and compressive strength of cement-silica fume paste. After the surface was modified with aminopropyltriethoxysilane and magnetic stirring process, surface potential of silica fume changed from ?21 mV to +3 mV, adsorption capacity to high performance polycarboxylate-based superplasticizer increased by 60%. Quantity of nano-scale fine particles in the silica fume increased significantly, agglomeration to large particles decreased obviously, and dispersibility of silica fume particles improved greatly. Mechanical properties of cement-silica fume paste were improved by 11%~24% due to the modified silica fume. After surface modification is applied to original silica fume using amino siloxane and magnetic stirring process, surface potential of silica fume is changed from negative to positive, superplasticizer adsorption capacity is increased significantly, agglomeration of particles is reduced, quantity of nano-scale particles is increased, and dispersibility in cement is improved, ITZ performance of cement-silica fume hydration products is improved, and mechanical properties of cement-silica fume paste is greatly improved.