电阻率法计算内养护混凝土氯离子扩散系数

Calculation of chloride diffusion coefficient of internal curing concrete based on electrical resistivity

基于Nernst-Plank方程,引入构成因子的概念,分析了混凝土孔隙溶液离子组成和浓度对混凝土电导性的影响,建立了基于混凝土电阻率的氯离子扩散系数计算模型.通过混凝土电阻率测试试验,讨论了水胶比、内养护作用、养护条件对内养护混凝土电阻率及孔隙迂曲度的影响,并对比了自然浸泡试验得到的氯离子扩散系数.结果表明:低水胶比内养护混凝土有着更大的电阻率和孔隙迂曲度,养护环境中湿度的改变对混凝土电阻率和孔隙迂曲度的影响较小;电阻率法可以在一定程度上反映混凝土中氯离子传输性能的相对强弱,该方法得到的混凝土氯离子扩散系数与自然浸泡法得到的结果符合良好的线性相关关系.

Based on the Nernst-Plank equation,the formation factor was introduced to analysis the influence of ion composition and concentration of concrete pore solution on its conductivity,and a chloride ion diffusion coefficient calculation model based on concrete resistivity was established.Through the concrete resistivity test,the influence of water-binder ratio,internal curing effect and curing conditions on the internally cured concrete resistivity and pore tortuosity was discussed,and the chloride diffusion coefficient obtained by ponding test and resistivity test was compared.Results show that the internal curing concrete with low waterbinder ratio has greater resistivity and pore tortuosity than that of the ordinary concrete,and the curing condition has less influence on the resistivity and pore tortuosity of concrete;the concrete resistivity can reflect the chloride ion transport performance in concrete to a certain extent,and the chloride ion diffusion coefficient of concrete obtained by the resistivity test has a good linear correlation with the results obtained by ponding test.