In this study, the deterioration resistant of concrete with and without multi‐walled carbon nanotubes (MWCNTs) against combined freeze–thaw cycles and sulfate attack was studied, and concretes incorporating MWCNTs (i.e., 0.05, 0.10, and 0.15 wt%) as partial replacement of Portland cement were exposed to 5% sodium sulfate solution under freeze–thaw cycles. The performance, including compressive strength, relative dynamic elastic modulus, mass loss, microstructure, deterioration resistant coefficient of concretes were evaluated. Results show that when exposed to 5% sodium sulfate solution, MWCNTs could enhance the mechanical and durability properties of concrete subjected to combined freeze–thaw cycles and sulfate attack, regardless of the dosage of MWCNTs. The deterioration resistant of MWCNTs concrete was not increase with the increase dosage of MWCNTs. And the best resistance performance was obtained in concrete containing lower dosage of MWCNTs. In addition, MWCNTs could promote formation of hydration and corrosion products, and delay deterioration of concrete was demonstrated by SEM and thermogravimetric analysis.

中文翻译：

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MWCNT's用量对冻融循环和硫酸盐侵蚀共同作用下混凝土抗变质性的影响

在这项研究中，研究了具有和不具有多壁碳纳米管（MWCNT）的混凝土对组合的冻融循环和硫酸盐侵蚀的抗变质性，并且部分掺入了MWCNT（即0.05、0.10和0.15 wt％）的混凝土波特兰水泥的替代品在冻融循环下暴露于5％的硫酸钠溶液中。评估了混凝土的性能，包括抗压强度，相对动弹性模量，质量损失，微观结构和抗变质系数。结果表明，当暴露于5％的硫酸钠溶液中时，无论MWCNTs的用量如何，MWCNTs都能增强混凝土的机械和耐久性，同时经受冻融循环和硫酸盐侵蚀。MWCNTs混凝土的抗劣化性能并没有随着MWCNTs用量的增加而增加。在含有较少量多壁碳纳米管的混凝土中，获得了最佳的抵抗性能。此外，多壁碳纳米管可以促进水化和腐蚀产物的形成，并且通过SEM和热重分析证明了混凝土的延迟劣化。