本文测定了早龄期与长龄期粉煤灰水泥及硅酸盐水泥硬化浆体中Cl~-离子的有效扩散系数。发现Cl~-离子在成熟的粉煤灰水泥浆体中的扩散系数远比纯水泥浆体为小。粉煤灰品质,特别是勃氏比表面对有效扩散系数有重要影响。本文还对扩散系数与浆体孔隙率的关系作了探讨。 In this paper, the effective diffusion coefficients of Cl- ions in fly ash cement and Portland cement hardened pastes at early age and long age were measured. It was found that the diffusion coefficient of Cl~-ion in the mature fly ash cement slurry is much smaller than that of the pure cement slurry. The fly ash quality, especially the Blaine’s ratio surface, has an important influence on the effective diffusion coefficient. This article also discusses the relationship between the diffusion coefficient and the porosity of the slurry.