中文摘要：

建立了含毛细裂缝水泥石中等效氯离子扩散的细观模型,模型中毛细裂缝相当于氯离子扩散的快速通道。首先构造了含一条毛细裂缝的细观单胞（Unit Cell,UC）中氯离子的浓度分布,推导了等效扩散系数的表达式。在此基础上建立了包含多条随机毛细裂缝的细观代表性体积单元（Representative Volume Element,RVE）,得到了等效氯离子扩散系数与毛细裂缝密度之间的关系。并分别建立了UC和RVE的细观有限元模型,验证了氯离子扩散理论模型的合理性。以此为基础,推导了便于工程应用的水泥石中氯离子扩散系数随孔隙率变化的简化表达式,试验数据验证了其合理性。

英文摘要：

A micro model on average chlorine ion diffusivity of cement involving capillary cracks has been established. Capillary cracks in this model were equivalent to fast tracks of chlorine ion transporting. Firstly,chlorine ion concentration field in unit cell（ UC） with one capillary crack was modeled and average diffusivity overall the UC was related to crack length. Based upon this UC model,representative volume element（ RVE） of cement containing a number of dispersed capillary cracks random both in length and angle was built. From the RVE,the dependence of equivalent chlorine ion diffusivity to capillary crack density and the was formulated. M icro finite element models of UC and RVE have been established also in order to verify the theoretical models. For meeting engineering application,a simplified prediction of chlorine ion diffusivity verses porosity in cement was deduced from the model developed above and it has been validated by experimental data.