COMSOL Simulation of Diffusion Process of Cl^- in Cracked Concrete T-Beam

The current research on chloride ion erosion could not reflect the law of chloride ion diffusion in reinforced concrete under the action of multiple factors. A reinforced concrete T-beam was used as the object, and the three-dimensional numerical model of T-beam was established by finite element analysis software of COMSOL multiphysics coupling. The influence of crack depth and width on the diffusion process of chloride ion in concrete and its durability service life was discussed in detail. It was found that the chloride ion diffusion model considering the steel bar retardation, adsorption reaction and crack size could be introduced into the T beam durability study, which could more accurately reflect the distribution of chloride ion concentration field in the T beam; the size of the crack enormously impact chloride ion diffusion. The larger the crack size, the greater the diffusion rate of chloride ions. The crack depth mainly affect the lateral diffusion of chloride ions around the crack, while the crack width mainly affect the diffusion of chloride ions along the depth direction. The concrete was affected by the retardation effect of the steel. The lateral distribution of the internal chloride ion concentration shows the variation of the waveform. The maximum point of the concentration was located at the axis of the longitudinal reinforcement, the minimum point was located at the gap between reinforcement and reinforcement, and the lateral variation gradient of the chloride ion concentration at the fracture was significantly lower than that of the unfractured concrete.