Numerical Simulation Of Chloride Ion Adhesion And Erosion Analysis Of Concrete Bridge In Salt Fog Area

With the widely application of the reinforced concrete bridge,more and more people pay attention to the durability of concrete bridges.The reinforcement corrosion is considered to be the first factors influencing the durability of concrete structures.A large number of studies worldwide show that chlorine ion erosion is the most im-portant factor leading to corrosion of steel reinforcement.The erosion process of chloride ion in concrete structure is complicated,and it is influenced by many factors.The chloride ion concentration of concrete surface is an important factor in the pro-cess of chlorine ion erosion.In the Marine environment,the chloride ion of the bridge upper structure mainly comes from the salt fog and is influenced by the sea breeze and the shape of the bridge.Therefore,it is necessary to determine the chloride ion con-centration of the concrete bridge in the marine environment.Based on the existing research theories and methods,this paper considers the spatial variability of chloride ion concentration on concrete bridge surface.Firstly,the theoretical analysis of the force of chloride ions in the marine environment were car-ried out,and the calculation method of chloride adhesion on the surface of the bridge was determined.The two-dimensional model of concrete bridge was established by using computational fluid dynamics software(CFX)as the platform,and the relation-ship between the amount of chloride adhesion on the bridge surface and the shape of the bridge was explored.The influence of wind speed and particle diameter on the chloride adhesion on the bridge surface was determined by parametric analysis.Ac-cording to the terrain conditions of the bridge,a three-dimensional model was estab-lished to analyze the effect of terrain conditions on the chloride adhesion on the bridge surface.Three-dimensional simulation results and two-dimensional simulation results were compared and analyzed to evaluate the rationality of two-dimensional simplified model.The influence of wind speed and particle diameter on chloride ion attaching amount in three-dimensional simulation was analyzed.Finally,based on the numerical simulation of the chloride adhesion on the bridge surface,the concrete erosion process are calculated and analyzed.The effects of chloride ion deposition,water-cement ratio and protective layer thickness on chloride ion attack were inves-tigated by parametric analysis.In this paper,through the numerical simulation of the concrete bridge,it is con-cluded that the chloride ion attachment on the bridge surface is influenced by the shape of the bridge and the terrain conditions,which can be used for the durability design of the concrete bridge.Through the analysis of the chloride ion erosion process in the marine environment,the effective measures to prevent the chloride ion erosion of the concrete bridge are obtained.