锈蚀速率对混凝土中锈蚀产物渗透的影响

Influence of corrosion rate on rust penetration in concrete

钢筋出现锈蚀后锈蚀产物会在保护层孔隙中扩散,延缓锈胀裂缝发展.为提高从保护层裂缝宽度推算钢筋锈蚀率的准确性,设计不同外加电流密度的通电加速锈蚀实验,使钢筋以不同锈蚀速率发生锈蚀,基于结合X射线计算机断层成像和有限元的逆向建模方法计算锈蚀产物体积修正系数,量化锈蚀产物渗透,分析锈蚀速率的影响.结果表明,随着钢筋锈蚀速率的增大,锈蚀产物渗透减少,锈蚀产物体积修正系数增大;随着钢筋锈蚀过程发展,锈蚀产物体积修正系数减小,但减小过程与锈蚀速率无关;锈蚀产物体积修正系数随着钢筋锈蚀率的增大呈指数减小.研究结果可为钢筋混凝土结构的钢筋锈蚀评估提供依据.

Rust penetration in pore structure of concrete cover happens after the reinforcement corrosion,which impedes the cracking development.To improve the accuracy of deducing the corrosion level of reinforcement from the crack width,reinforcements are designed to be corroded with different corrosion rates using different impressed current densities.Based on an inverse modeling method that consists of a combination of X-ray micro-computed tomography and the finite element method,the development of the modification coefficient of the rust volume is calculated to quantify the rust penetration and the influence of the corrosion rates.The results indicate that as the corrosion rate increases,the rust penetration decreases,and the modification coefficient of the rust volume increases.As the corrosion process develops,a decrease in the modification coefficient of the rust volume is found,which is independent of the corrosion rate.The modification coefficient of the rust volume decreases exponentially with the increase of corrosion rate.This study could provide a basis for the evaluation of reinforcement corrosion of reinforced concrete structures.