近海环境下钢筋非均匀锈蚀引起混凝土保护层开裂的数值模拟

Numerical simulation of concrete cover cracking induced by rebar non-uniform corrosion in offshore environment

根据近海环境下的钢筋混凝土结构受到碳化和氯盐的双重侵蚀,建立了非均匀锈蚀层分布的数学模型。以此为基础,提出了钢筋锈蚀层分布不均匀系数k,用以评判钢筋锈蚀层分布不均匀程度。针对同一钢筋平均截面锈蚀率、不同k值下的有限元分析结果表明:(1)锈胀裂缝首先出现位置为13.5°、166.5°附近,且与钢筋锈蚀层分布不均匀程度无关;(2)钢筋锈蚀层分布不均匀性增加,钢筋/混凝土界面的环向拉应力增大,引起混凝土保护层提前开裂。因此,在分析钢筋锈蚀引起混凝土保护层开裂,以及评价钢筋混凝土结构耐久性寿命时,钢筋锈蚀层分布不均匀程度应作为一个重要参数进行综合考虑。

According to the double erosion of carbonation and chloride salt in reinforced concrete structure under the offshore environment,a mathematical model of non-uniform corrosion layer distribution is established.On this basis,the non-uniform distribution coefficient k of rebar corrosion layer is put forward to judging the non-uniform distribution degree of rebar corrosion layer.In the condition of the same rebar average section corrosion rate and different k values,the finite element analysis results show that（1）concrete cover cracking first occurs near the location for the 13.5° and 166.5°,and is no accordance with the non-uniform distribution degree of rebar corrosion layer.（2）the distribution degree of rebar corrosion layer is more non-uniform,and the steel/concrete interface ring tensile stress increases,which leading to the concrete cover early cracking.Therefore,when analyzing the concrete cover cracking induced by rebar corrosion and evaluating the durability life of reinforced concrete structure,the non-uniform distribution degree of rebar corrosion layer can be considered as an important parameter.