钢筋非均匀锈蚀与混凝土开裂试验及数值模拟

Experimental and Numerical Simulation on Non‑uniform Corrosion of Steel Bar and Concrete Cracking

采用恒电位驱动氯离子渗透并加速钢筋锈蚀来模拟海洋钢筋混凝土锈蚀,研究了水胶比、保护层厚度和钢筋直径对试件锈胀开裂的影响;利用COMSOL Multiphysics软件建立了真实骨料混凝土模型并进行数值模拟.结果表明:本试验制备的混凝土试件在恒电位加速锈蚀下钢筋发生非均匀锈蚀并导致混凝土产生3条主裂缝,钢筋临界锈胀应力为2.85~3.51 MPa,开裂时间为190~311 h,降低水胶比及增大保护层厚度均可延缓锈胀开裂时间;数值模拟可以很好地再现钢筋混凝土非均匀锈蚀过程,其获得的锈胀应力演变及混凝土开裂模式与试验结果吻合.

To simulate the corrosion of reinforced concrete,chloride penetration was drove under constant potential.The effects of water to cement ratio,cover thickness,and steel bar diameter on the rust expansion cracking of specimens were studied.Additionally,the concrete model of real aggregate was established to simulate using COMSOL Multiphysics software.The results show that non-uniform corrosion of steel bar occurs and leads to three main cracks in concrete under constant potential accelerated corrosion.The rust expansion stress of concrete specimen is 2.85-3.51 MPa and the cracking time is 190-311 h in this experiment.Moreover,the cracking time of specimens can be delayed by reduction of the water to cement ratio and increase of the cover thickness.The numerical simulation can well reproduce the non-uniform corrosion process of reinforced concrete,and the evolution of rust expansion stress and crack development is consistent with the test results.