混凝土Cl-扩散系数预测的有限元方法

提出了预测混凝土Cl^-扩散系数的有限元方法．将混凝土看成是一种由骨料、界面和水泥浆基体所组成的三相复合材料，通过比较两种典型的单元细胞模型，说明了圆形单元细胞模型在混凝土模拟方面的优越性．由于界面厚度远小于骨料尺寸，采用推进前沿法尽可能准确地剖分单元细胞，应用有限元方法获得了混凝土Cl^-扩散系数的数值解．将数值结果与实验数据进行比较，验证了该方法的有效性．基于数值结果，定量评价了最大骨料粒径、界面Cl^-扩散系数、界面厚度和骨料级配对混凝土Cl^-扩散系数的影响．

Finite Element Method for Predicting Chloride Diffusion Coefficient in Concrete

A finite element method is presented for predicting chloride diffusion coefficient in concrete.First,concrete is considered as a three-phase composite material consisting of aggregate,interfacial transition zone(ITZ) and cement paste.By comparing two typical unit cell models the advantage of the circular unit cell model in simulating concrete is demonstrated.Since the ITZ thickness is much smaller than the aggregate size,the advancing front method is adopted to divide the unit cell as accurately as possible.The finite element method is then used to obtain the numerical solution for the chloride diffusion coefficient in concrete.Finally,the validity of the method developed is verified by comparing the numerical results with the experimental data.Based on the numerical results,the effects of maximum aggregate diameter,chloride diffusion coefficient of ITZ,ITZ thickness and aggregate gradation on the chloride diffusion coefficient in concrete are evaluated in a quantitative manner.