钢筋锈胀作用下混凝土的抗压强度退化模型

Degradation Model of Compressive Strength of Concrete under the Action of Steel Bar Rust Expansion

在杂散电流作用下,混凝土内钢筋发生电化学锈蚀,产生锈胀应力。为了研究在混凝土尚未出现裂缝阶段钢筋锈蚀对混凝土抗压强度的影响,以钢筋均匀锈蚀为前提,将混凝土内钢筋锈蚀分为有和无锈胀应力2个阶段,给出锈胀应力的产生时间。利用Faraday电解定律、弹性力学厚壁筒应力理论以及混凝土二轴强度破坏准则研究杂散电流腐蚀钢筋对混凝土抗压强度的影响,得到了混凝土抗压强度理论退化模型。对模型进行分析表明:杂散电流作用下,钢筋锈蚀产生的锈胀应力会对混凝土抗压强度产生不利影响。最后将理论模型与试验进行对比分析,证明该模型在分析杂散电流腐蚀钢筋对混凝土抗压强度的影响上具有一定可行性。

Under the action of stray currents,electrochemical corrosion of reinforcement in concrete occurs,resulting in rust swelling stresses.In order to study the effect of reinforcement corrosion on the compressive strength of concrete at the stage when cracks have not yet appeared in concrete,the corrosion of reinforcement in concrete is divided into two stages with and without rust swelling stresses,and the generation time of rust swelling stresses is given,taking the uniform corrosion of reinforcement as a premise.And using Faraday's law,elastic mechanics thick-walled cylinder stress theory and two-axis damage criterion to study the effect of stray current corrosion reinforcement on the compressive strength of concrete,the theoretical degradation model of concrete compressive strength was obtained.The analysis of the model shows that the rust swelling stresses generated by the corrosion of reinforcement under the action of stray currents will adversely affect the compressive strength of concrete.Finally,the theoretical model was compared and analyzed with the test,which proved the feasibility of the model in analyzing the effect of stray current corrosion of reinforcement on the compressive strength of concrete.