【摘要】 文章采用偶联剂KH550改性后的纳米SiO₂与丙烯酸甲酯（MA）、乙二胺（EDA）进行反应，再将甲氧基聚乙二醇-丙烯酸酯（MPEG-DA）接枝在经过MA和EDA扩链处理后的纳米SiO₂表面。采用傅里叶变换红外光谱仪（Fourier transform infrared spectrometer, FTIR）和热失重分析仪（thermogravimetric analyzer, TGA）对MPEG-DA改性的纳米SiO₂的结构进行表征，并分析掺杂纳米SiO₂和MPEG-DA改性纳米SiO₂水泥浆体的水化过程、微观结构以及孔径分布。结果表明：MPEG-DA改性纳米SiO₂可以调控水泥浆体水化过程、精炼水泥试件的微观结构，抑制水泥试件的孔隙率的增加；MPEG-DA改性纳米SiO₂不仅能优化水泥基材料的施工性能，还可以显著强化水泥基材料的力学强度；在MPEG-DA改性纳米SiO₂的掺量为胶凝材料质量的0.5%时，砂浆和混凝土28 d的抗压强度较空白样增长了43.1%和27.8%。更多还原

【Abstract】 On the base of nano-SiO₂ modified by KH550, the surface of nano-SiO₂ was treated with methyl acrylate（MA） and ethylenediamine（EDA） for chain extension, and then methoxy polyethylene glycol diacrylate（MPEG-DA） was anchored onto the nano-SiO₂ surface. The specific structure of MPEG-DA modified nano-SiO₂ was characterized by Fourier transform infrared spectrometer（FTIR） and thermogravimetric analyzer（TGA）. The hydration process, electron microscopic patterns and pore size distribution of cement pastes doped with nano-SiO₂ and MPEG-DA modified nano-SiO₂ were analyzed. The results show that MPEG-DA modified nano-SiO₂ can control cement paste hydration process, refine the microstructure and decrease the porosity of cementitious material. Besides, the nano-SiO₂ modified by MPEG-DA not only can optimize the workability of cement-based materials, but also can enhance their mechanical strength. When the content of MPEG-DA modified nano-SiO₂ was 0.5% of cementitious material, the compressive strength of fabricated cement mortar and concrete increased by 43.1% and 27.8%, respectively, compared to the reference sample after curing for 28 days.更多还原