硅灰混凝土表观氯离子扩散系数影响因素的研究

Influence Factors on Apparent Chloride Diffusion Coefficient of Silica Fume Concretes

通过自然扩散法测定了硅灰混凝土在高浓度氯盐介质中浸泡不同时间后自由氯离子的浓度分布,研究了硅灰混凝土表观氯离子扩散系数与硅灰掺量、养护时间、暴露时间以及溶液种类的关系。结果表明:掺加适量的硅灰可以有效减小混凝土表观氯离子扩散系数;增加养护时间将降低硅灰混凝土表观氯离子扩散系数;硅灰混凝土的表观氯离子扩散系数在3种溶液中的大小顺序为:3.5%Na Cl+5%Mg SO4溶液>3.5%Na Cl溶液>青海盐湖卤水。

The natural diffusion method was adopted to investigate free chloride concentration profiles of ordinary Portland concrete and silica fume concrete exposed to the chloride medium of high concentration at different times,and to examine the relationship among the apparent chloride diffusion coefficient of concretes and silica fume contents,curing time,the exposure time and the solution species.The results showed that adding silica fume effectively reduced the apparent chloride diffusion coefficient of concrete,extending the curing time reduced the apparent chloride diffusion coefficient of silica fume concrete and apparent chloride diffusion coefficient of silica fume concrete in 3 solution species in the order of： 3.5%Na Cl ＋ 5% Mg SO4 solution 〉3.5% Na Cl solution 〉Qinghai Salt Lake brine.