混凝土保护层均匀锈胀内裂分析

Analysis on the internal cracking of concrete cover due to rebar uniform corrosion

钢筋锈蚀是影响钢筋混凝土结构使用寿命的重要因素,混凝土保护层锈胀内裂加速整个混凝土保护层的开裂。假定混凝土满足最大伸长线应变破坏准则,利用圆孔扩张理论对铁锈自由膨胀充满混凝土与钢筋交界面空隙后混凝土保护层内裂进行分析,建立了锈胀内裂时刻的钢筋锈蚀深度计算式。针对计算式主要影响参数的分析表明:钢筋锈蚀深度与水泥石中毛细孔体积、钢筋直径、混凝土极限拉应变成正相关,与铁锈体积膨胀率成负相关。

Rebar corrosion is an important factor affecting the service life of reinforced concrete structures.Concrete cover internal cracking induced by reinforcement corrosion accelerates cracking of all cover.Based on the assumption of concrete meet the maximum tensional strain failure criterion,one equation for predicting the reinforcement corrosion depth from corrosion initiation to cover internal cracking was established according to the cylindrical cavity expansion theory.By analyzing main parameters of the equation,the results showed that the reinforcement corrosion depth was positive correlation with cement stone pore volume,diameter of rebar,concrete ultimate tensile strain,and negative correlation with rust rate of volume expansion.