Research On The Whole Process Of Corrosion Damage Of Reinforced Concrete Based On Electrochemical Impedance Spectroscopy

Corrosion of reinforced concrete in reinforced concrete has always been the main reason affecting the durability of the structure.Corrosion and cracking of the surrounding concrete caused by corrosion of reinforced steel has gradually become one of the hot topics of research.By adding fibers to the concrete and utilizing the reinforcing effect of the fibers,the tensile strength and toughness of the concrete can be improved,the crack resistance of the concrete can be improved,and the concrete material can be made more high-performance.In this paper,PVA fiber reinforced concrete is used as the research object.The rust expansion and cracking law of reinforced concrete specimens with different water-cement ratios and different fiber contents under the condition of chloride salt as an aggressive substance is studied.From the perspective of improving the durability of reinforced concrete Starting from the optimal amount of fiber,in order to provide a theoretical basis for the reasonable use of PVA fiber concrete.The research content of this article includes the following aspects:(1)Assuming that the corrosion of the steel bar is uniform,the derivation formula of the critical rust expansion force of the reinforced concrete considering the damage mechanics is analyzed by simplifying the reinforced concrete specimen into a thick-walled cylindrical model.According to this formula,the critical rust expansion force of reinforced concrete under different crack lengths can be calculated.(2)The potentiostatic accelerated corrosion test,corrosion potential monitoring,and electrochemical impedance spectroscopy tests were performed on 15 groups of reinforced concrete specimens with different water-cement ratios and PVA fiber content,which simulated the whole process of corrosion damage cracking of reinforced concrete under uniform corrosion.By comparing the change of corrosion potential with the rust time and the electrochemical impedance spectroscopy at different rust stages,it was found that fiber-reinforced concrete can significantly delay the rust rate of steel bars in concrete,mainly because the presence of fibers in the concrete can prevent the rust products from entering the concrete.It is determined that from the perspective of improving the durability of PVA fiber concrete,the optimal amount of PVA fiber is 0.8%.(3)Using ABAQUS finite element software,based on the experimental content of this paper,the numerical simulations of the entire process of rust expansion and cracking of ordinary concrete and fiber-reinforced concrete protective layers were performed.The simulation results are consistent with the experimental analysis results in this paper.At the same time,the feasibility of ABAQUS in the research on the whole process of corrosion cracking of reinforced concrete was also verified.