| The rebar rust in the reinforced concrete bridge is the number one killer whose structure is durable,while the most active bridges in our country are reinforced concrete structures,so the measurement of reinforcement rust in the bridge is very important.In recent years,the detection technology of rebar rust based on Eddy current thermal imaging is a kind of nondestructive and effective,green and environmental protection of the new steel corrosion detection technology,the research of this technology at home and abroad stay in the qualitative evaluation of the testing material defects.After completing the theoretical analysis of the steel corrosion detection based on Eddy current thermal imaging,this paper carries out the indoor Eddy current induction heating experiment,and combines with the finite element simulation to analyze the relationship between the surface temperature growth rate of the reinforced concrete induction heating and the corrosion time of the steel bar,and the influence of each working condition on the The measurement model of reinforcement rust and the determination formula of reinforcement rust are further established,and the reliability of the quantization method is validated by the experimental results,and the quantitative method of measuring the steel bar rust inside the bridge by the Eddy current thermal imaging is applied to the real bridge.The research of this paper provides some guidance for the development of the following Eddy current thermal imaging nondestructive quantification technology.The main research contents of this paper are:①Finishing the domestic and foreign references related to eddy current thermal imaging technology,understanding the current research situation of Eddy current thermal imaging technology at home and abroad,developing the measuring mechanism of reinforcement rust measurement based on Eddy current thermal imaging,and analyzing the mechanism of surface temperature change of reinforced concrete by induction heating,The influence of different working conditions on the surface temperature variation of reinforced concrete is studied.②The experiment of induction heating of bare steel bars and reinforced concrete induction heating experiments were carried out,from the angle of experiment,the change regularity of the surface temperature growth rate of reinforced concrete with the reinforcement rust time and the influence of the temperature growth rate of reinforced concrete surface on the corrosion time were studied.③A three-dimensional finite element simulation model of ANSYS was established to calculate the heat conduction of concrete after stopping induction heating,and the process of concrete heat conduction The growth rate of the surface temperature of reinforced concrete increases with the time of reinforcement corrosion and the influence of the temperature growth rate of reinforced concrete surface on the time of corrosion.④Combined with the physical equation of the surface temperature and the physical equation of heat conduction surface temperature of the bare reinforcement,a physical model for testing the corrosion degree of steel bar is established,and the dimensionless ratio of the surface temperature growth rate of corroded specimen and the rusty specimen is used as the quantitative index of the corrosion degree of steel bar to eliminate the influence of each working condition on the surface temperature growth rate.Based on the finite element model of AN SYS,the quantitative indexes of different models are studied,and the formula for determining the corrosion degree of steel bar is proposed,and the quantitative method is proved to be accurate and effective through experimental results.⑤Based on the project of the high speed k131+920 in Yunnan province,this paper uses the Eddy current thermal imaging method to detect the reinforcement rust measurement in the bridge,and the real bridge test results show that the method is accurate and reliable,and has practical engineering application value. |
PDF Full Text Request