This paper aims to investigate the freeze-thaw resistance of cement-paste containing with different diameter and content of multiwalled carbon nanotubes (MWCNTs) in terms of mechanical properties and microstructure. Three groups of cement-paste with MWCNTs diameter of 10-20 nm, 20-40 nm and 40-60 nm were prepared by incorporating 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt% MWCNTs by cement weight. Experimental results showed that the addition of 0.1 wt% MWCNTs with diameters of 10–20 nm effectively improved the freeze-thaw resistance of cement-paste. In addition, microstructural analysis of these cement-paste specimens showed that MWCNTs addition increased the materials’ initial porosity, but a proper amount of MWCNTs decreased the porosity of cement-paste after freeze-thaw cycles and effectively improved the pore size distribution. MWCNTs 10–20 nm in diameter were found to be the optimal size for improving the microstructure of these MWCNTs cement-paste

本文旨在研究不同直径和含量的多壁碳纳米管（MWCNTs）所含水泥浆的抗冻融性能，包括力学性能和微观结构。通过掺入水泥中的0.1 wt％，0.2 wt％，0.3 wt％，0.4 wt％，0.5 wt％MWCNT制备三组MWCNT直径为10-20 nm，20-40 nm和40-60 nm的水泥浆重量。实验结果表明，添加直径为10–20 nm的0.1 wt％MWCNT可以有效提高水泥浆的抗冻融性。此外，对这些水泥浆样品的微观结构分析表明，MWCNTs的添加增加了材料的初始孔隙率，但是适量的MWCNTs冻融循环后降低了水泥浆的孔隙率并有效地改善了孔径分布。