钢筋锈蚀导致混凝土构件保护层胀裂的全过程分析

Analysis on the cracking of concrete cover due to rebar corrosion

本文描述了从钢筋锈蚀开始直至因钢筋锈蚀而导致混凝土保护层胀裂的整个过程,包括铁锈自由膨胀阶段、混凝土保护层受拉应力阶段和混凝土保护层出现胀裂裂缝阶段,总锈蚀深度是3个阶段深度之和。据此,建立了混凝土保护层胀裂时钢筋锈蚀深度的计算模型,以计算该时刻的钢筋锈蚀深度。分析了影响混凝土保护层胀裂时钢筋锈蚀深度的各个因素,包括混凝土水泥石毛细孔的体积、混凝土保护层的厚度、钢筋直径和铁锈膨胀率。与已有的试验结果对比表明,本文建立的混凝土保护层胀裂时钢筋锈蚀深度的计算模型,与试验结果符合较好。

The process of rebar corrosion from the beginning of rusting to the occurrence of concrete cover cracking due to corrosion expansion may be divided into three periods： period of free expansion of the corrosion product, period of stress initiation of concrete cover and period of cracking of concrete cover. The total depth of corrosion is the sum of the corrosion depths formed in these periods. A model for calculating the corrosion depth at the moment of cracking due to corrosion expansion is established. The factors influencing the corrosion depth including the porous volume of concrete, thickness of concrete cover, diameter of rebar and the corrosion expansion rate are analyzed. The calculation result of this proposed model is in good agreement with experimental data.