角部钢筋锈蚀引发混凝土保护层开裂行为研究

Investigation on Cracking Behavior of Concrete Cover Induced by Corner Located Rebar Corrosion

为研究角部钢筋非均匀锈蚀膨胀引发的混凝土保护层开裂行为,提出了角部钢筋的非均匀锈胀模式.并将混凝土视为由骨料、砂浆和界面过渡区组成的三相复合材料,建立了混凝土细观随机骨料模型.以施加非均匀径向位移方式来表征钢筋锈胀对周围混凝土的力学作用.基于该方法对钢筋非均匀锈蚀引发的混凝土保护层开裂行为进行了细观数值模拟,模拟结果与已有文献中试验结果的良好吻合验证了该方法的合理性.另外,对比了宏观均质模型和细观非均质模型下不同角部钢筋锈胀模式导致的混凝土保护层开裂模式;并探讨分析了保护层厚度和钢筋直径对保护层开裂模式以及钢筋锈胀压力的影响规律.

In order to investigate cracking behavior of concrete cover induced by corner located rebar corro- sion expansion, a non-uniform corrosion expansion model of corner located rebar was established. Concrete was regarded as a three-phase composite material composed of coarse aggregate, mortar and the interracial transition zone（ITZ） and a meso-scale random aggregate model of concrete was built. Non-uniform radial displacement was adopted in this model to simulate corrosion behavior of rebar. Based on the model, the cracking process of concrete cover was explored. The simulation results show good agreement with the available test results, which verifies the reasonability of the present method. Moreover, the failure pat- terns of concrete cover under different corrosion patterns of rebar obtained from the macro-scale homoge- neous model and meso-scale heterogeneous model were compared. Influences of concrete cover thickness and rebar diameter on the failure pattern of concrete cover and expansive pressure were investigated.