The effects of nano-SiO₂ (NS) and nano-TiO₂ (NT) on the microstructure, strength and chloride diffusivity were compared, and the mechanism of both nanoparticles on early-age frozen cement paste was revealed. The thermogravimetric (TG) results demonstrate that NS effectively increases C-S-H gel content and degree of hydration to make up for hydration loss due to early-age frost attack, while NT had little effect on compensating for hydration loss. The mercury intrusion porosimetry (MIP) results indicate that NS and NT have the same improvement mechanism for frost-damaged pore structures, while NS has a better improvement effect on pore structure than NT. The macro results show that the enhancement effects of NS and NT on strength are similar, while the improvement effect of NS on chloride diffusivity is much better than that of NT. Finally, it is concluded that, in the early-age frozen cement paste, NS promotes cement hydration and optimize pore structure through pozzolanic effect, while NT mainly improves pore structure through nano-filling effect.

_{纳米SiO 2} (NS)和纳米TiO ₂的作用比较了 (NT) 对微观结构、强度和氯离子扩散率的影响，并揭示了两种纳米粒子对早期冷冻水泥浆体的作用机理。热重（TG）结果表明，NS 有效地增加了 CSH 凝胶含量和水化程度，以弥补由于早期霜冻侵袭造成的水化损失，而 NT 对补偿水化损失的作用很小。压汞法（MIP）结果表明，NS和NT对冻害孔隙结构的改善机制相同，但NS对孔隙结构的改善效果优于NT。宏观结果表明，NS和NT对强度的增强效果相似，而NS对氯离子扩散系数的改善效果远好于NT。最后得出的结论是，