Experimental Study On Corrosion Detection Of Reinforced Concrete Structure Based On Pulse Eddy Current

Reinforcement corrosion is a kind of common damage regarding structural durability failure in the reinforced concrete.It may lead to the failure in advance of the service structure when the corrosion becomes serious.Afterwards,it is likely to cause huge economic losses and casualties.Because normally the steel bars are wrapped inside the concrete,it’s difficult for the conventional detection techniques to evaluate the internal corrosion status.So an effective method to detect the corrosion situation quickly and effectively of reinforced concrete structure has become very significant.At present,the main corrosion detection technology can be classified into the destructive testing method and non-destructive testing method.Both of them have certain the advantages but also has its relevant limitations.Based on the pulsed eddy current testing theory,an experimental study on the corrosion of reinforced concrete structure was launched through theoretical analysis,experiment tests and simulation analysis.The main research contents are as follows:① Based on the analysis of the corrosion mechanism of reinforced concrete structure,a set of electromagnetic pulse eddy current testing system was established.A new type of eddy current testing probe is proposed by studying the improvement of the detection sensitivity of reinforced concrete corrosion.By adding a U-shaped permalloy core as the excitation probe,the effective use of the optimal maximum vertical magnetic field component function can achieve the best detection result from the same lift off height.Thus,a reliable hardware foundation was laid for the experiment in this research.②Two kinds of corrosion schemes are designed to simulate the corrosion of reinforced concrete in nature.The tests of the bare steel bars specimens and reinforced concrete specimens were designed under the same excitation parameters and different influencing factors.From the two aspects of time domain and frequency domain,the eigenvalue of the signal was analysed,and then the similarities and differences between the test results of bare steel bars and reinforced concrete were obtained.By the above analysis,a new criterion for testing corrosion of reinforced concrete by pulsed eddy current testing was presented③The simulation analysis of the corrosion of reinforced concrete was performed based on the ANSYS FEA software.According to the geometry of the new probe and the electromagnetic field theory,the calculation model was established,and the simulated results were compared with the experimental results.Under the same corrosion condition,the experimental results and the calculated results are same,and the numerical difference is not significant.It is proved that the pulse eddy current testing method and the corresponding testing system is effective and reliable.Based on the above research,the method of detecting the corrosion of reinforced concrete structure with the new probe are feasible and applicable.The results of this paper can provide a theoretical and experimental basis for the subsequent research and development of the pulse eddy current testing of reinforced concrete corrosion.