【摘要】 为研究纳米SiO₂对混凝土抗硫酸盐侵蚀性能的影响，本文将掺有0%、0.5%、1.0%、2.0%、3.0%（质量分数，下同）纳米SiO₂的混凝土试件浸泡于5%（质量分数）硫酸钠溶液中进行抗硫酸盐侵蚀试验。研究了掺入纳米SiO₂的混凝土试件在干湿循环法加速硫酸盐侵蚀试验中的质量变化、相对动弹性模量、抗压强度损失系数及抗硫酸盐侵蚀性能的影响。结果表明，随着纳米SiO₂掺量的增加，混凝土的质量损失率、相对动弹性模量和抗压强度系数均呈先上升后下降的趋势。相比于NS0组，当纳米SiO₂掺量为2.0%时混凝土的各项性能最优。通过X射线衍射（XRD）和扫描电子显微镜（SEM）分析机理，发现掺入纳米SiO₂对混凝土内部微观结构有着良好的改善效果。纳米SiO₂能够加速水泥内部的水化反应，促进水化硅酸钙凝胶生成，并在内部形成相互交错的致密网状结构，进一步提高混凝土的密实度和抗硫酸盐侵蚀性能。更多还原

【Abstract】 In order to investigate the effect of nano-SiO₂ on resistance of concrete to sulfate attack, concrete specimens mixed with 0%, 0.5%, 1.0%, 2.0%, and 3.0%（mass fraction, same as below） nano-SiO₂ were immersed in 5%（mass fraction） sodium sulfate solution for sulfate attack experiment in this paper. The effects of concrete specimens mixed with nano-SiO₂ on mass change, relative dynamic elastic modulus, loss coefficient of compressive strength, and resistance to sulfate attack in the accelerated sulfate attack experiment by wet-dry cycling were investigated. The results show that as the content of nano-SiO₂ increases, mass loss rate, relative dynamic elastic modulus and loss coefficient compressive strength of the concrete show an increasing and then decreasing trend. Compared with the NS0 group specimens, when the nano-SiO₂ content is 2% the performance of concrete is the best. Through X-ray diffraction（XRD） and scanning electron microscopy（SEM） analysis mechanism, it is found that the addition of nano-SiO₂ has a good improvement effect on improving the internal microstructure of concrete. Nano-SiO₂ can accelerate the hydration reaction inside the cement, promote the formation of hydrated calcium silicate gel, and form an interlaced dense network structure inside, further improving the compactness and resistance of concrete to sulfate attack.更多还原