混凝土氯离子扩散系数时变性规律与计算模型适用性分析

Time variation of concrete chloride diffusion coefficients and applicability analysis of the calculation models

通过自然渗透试验直观展现了氯离子在混凝土中的扩散过程,研究了试验过程中氯离子扩散系数的计算模型.结果表明:氯离子向混凝土内部扩散是物理化学综合作用的复杂过程,其扩散系数是与时间相关的函数,衰减系数与胶凝材料种类、水胶比和暴露环境有关;由模型Ⅱ得出,养护时间与浸泡时间对计算混凝土短期浸泡试验氯离子扩散系数的影响不能忽略,而对长期浸泡试验,即当浸泡时间远大于养护时间时,其影响可以忽略.

Natural penetration tests intuitively show the chloride diffusing process in concrete.The calculation models for chloride diffusion coefficients are discussed in this paper.The analysis results show that： chloride diffusing into concrete is a complex process of physical and chemical effects,and the diffusion coefficients are the time-dependent functions,and the attenuation coefficients are related to cementitious materials,water cement ratio and exposure environment.According to model Ⅱ,for short term soaking experiment,the influence of a curing age and soaking time on the chloride diffusion coefficient calculation results cannot be neglected,whereas,for long term immersion experiment,namely when soaking time is far longer than the curing age,its influence can be neglected.