Corrosion monitoring of the RC structures in time domain: Part II. Recognition algorithm based on fractional derivative theory

•We directly extract the corrosion parameters of Rc((RctZw)ZCPE) in time domain.•We recognize the corrosion status by a fractional derivative algorithm.•The dispersion and diffusion effects are identified simultaneously.•Sampling frequency, duration and noise levels influence the recognition accuracy.

sTo identify the corrosion status of reinforced concrete (RC) structures, the fractional derivative (FD) theory is used to establish the integrated recognition algorithm. The electrochemical corrosion characteristics including dispersion and diffusion effects can be directly obtained in time domain. The effectiveness and accuracy of FD algorithm are verified numerically based on the results of complex-function-approximation algorithm. Furthermore, the robustness of FD algorithm is tested by the interference experiments of the white noise. The results indicate that the recognition algorithm established based on FD can successfully identify the corrosion status of RC structures in time domain.