中文摘要：

通过试验研究了文献中报道的几种依据菲克第二定律的氯离子表观扩散系数计算方法．试验结果表明：不同的计算方法所求的D值有很大差异；北欧标准NT Build443中采用最小二乘法计算表观氯离子扩散系数并不合适，在有些情况下会产生很大的误差；在这几种方法中，将表面氯离子浓度Cs值直接求出，每个深度计算出一个表观扩散系数值Di，然后取平均值计算表观扩散系数D的计算方法更适宜计算氯离子表现扩散系数；而在Cs和D作为常数考虑的情况下，几种计算方法绘制的氯离子浓度分布曲线都与试验数据有一定程度的差异．因此，菲克第二定律在描述氯离子在混凝土中的迁移时，不宜将Cs和D作为崤量考恿．

英文摘要：

The several calculating methods of apparent diffusion coefficient reported in published were investigated through some experiments. The experimental results show that it is not appropriate least-squares method for calculating apparent diffusion coefficient in NT Build 443, whose reason is some cases the method may produce relatively large error. In the several methods, the method in which the Cs as a measured value, most suitable for calculating papers to use that in making the D value is calculated by averaging the sum of Di at each measured depth is the the apparent diffusion coefficient. When considering Cs and D as constants, there exist differences in different degree between the experimental data and the chloride concentration distribution curves according to the several calculating methods of apparent diffusion coefficient. Therefore, when describing chloride migration in concrete by Fick＇s second law, it is not appropriate that Cs and D is regarded as constants.