角区钢筋非均匀锈蚀引发混凝土保护层开裂全过程研究

Concrete cover cracking behaviors induced by the non-uniform corrosion of corner-located rebars

综合考虑氯离子的扩散过程、钢筋锈蚀的质量守恒以及钢筋锈蚀引起的混凝土保护层开裂力学过程,以角区钢筋为研究对象,在钢筋周围施加随时间变化的非均匀径向位移,对氯离子侵蚀引起的混凝土保护层开裂全过程进行数值分析,得出了裂缝发展的分布规律、裂缝出现以及裂缝贯穿保护层所需的时间。并与实验结果进行对比,验证了模型的准确性。探讨了钢筋直径、混凝土保护层厚度以及混凝土强度的变化对混凝土保护层开裂行为及开裂时间的影响。结果表明,混凝土保护层厚度对开裂全过程影响最大,其次是钢筋直径,混凝土强度对其影响较小。

Considering the diffusion process of chloride ion, the mass conservation of steel corrosion and the concrete cover cracking mechanics, taking the corner-located rebar as a research object, the whole process of concrete cover cracking caused by chloride attack was numerically analyzed, by imposing a time-variant non-uniform radial displacement around concrete/steel interface. The distribution of crack development, and the time required for crack occurrence and for cracks to penetrate the concrete cover were obtained. The simulation results are in good agreement with the experimental results in an existing literature, and the rationality of the method was verified. The influences of rebar diameter, concrete cover depth and concrete strength on the concrete cover cracking behaviors and cracking time were discussed. The results show that the concrete cover depth has the greatest influence on the whole cracking process, followed by the rebar diameter. The concrete strength has little effect on the whole cracking process.