采用自然扩散法研究了普通混凝土、粉煤灰混凝土和矿渣混凝土在模拟海水环境中的氯离子扩散特性,探讨了养护龄期、暴露时间及矿物掺合料掺量对混凝土自由氯离子扩散系数的影响.结果表明:混凝土的自由氯离子扩散系数随着暴露时间的延长呈幂指数降低,而且其时间依赖性与养护时间及矿物掺合料掺量有关；当养护龄期达到730 d、粉煤灰和矿渣掺量(质量分数)分别达到30％和45％时,混凝土的自由氯离子扩散系数随暴露时间的降低速度最快；延长养护龄期及掺加粉煤灰和矿渣,对于降低混凝土的长期自由氯离子扩散系数具有重要的作用.%The chloride diffusion characteristics of ordinary Portland concrete, fly ash concrete and slag concrete exposed to substitute ocean water were investigated, and influences of curing age, exposing time and content of mineral admixture on free chloride diffusion coefficients of concrete were discussed by using the natural diffusion method. Results show that free chloride diffusion coefficients of concrete exponentially decrease with exposing time, and time dependence is related to curing age and content of mineral admixture. When curing age can reach 730 d, and contents (mass proportions) of fly ash and slag can reach 30% and 45% respectively, free chloride diffusion coefficients of concrete reduce most quickly with exposing time. Therefore, extending curing age and adding fly ash and slag have such a great impact on reduction of long-term free chloride diffusion coefficient of concrete.
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