关键词: 锈胀, 开裂轨迹, USDFLD子程序, 塑性损伤, 临界锈蚀率

Abstract: FEM models for corrosion-expansion cracks in reinforced concrete protective layer were built based on plastic damage theory. Corrosion-expansion correlation was simulated by loading displacement. Taking the maximum strain as the criterion, the concrete damage was achieved by reducing Young's modulus. The generating and propagating trajectories of internal and surface corrosion-expansion cracks were researched. For visually representing crack trajectories, a field variable under tensile condition was defined through a subroutine USDFLD in ABAQUS. The corresponding critical corrosion rates of the internal and surface cracks were calculated. The influences of the concrete cover thickness, reinforcement diameter and corrosion-expansion coefficient on the critical corrosion rates were studied. The results showed that the lateral cracks propagate from the surface of steel bar inside the concrete, while vertical cracks propagate from the surface of the concrete cover. The critical corrosion rates decrease with the increase of the bar diameter and corrosion-expansion coefficient. The effect of the corrosion expansion coefficient is more prominent, while the influence of protective layer thickness on the critical corrosion rate is not obvious.