The micro-solution electrochemical method to evaluate rebar corrosion in reinforced concrete structures

•A micro-solution electrochemical method is used to evaluate the rebar corrosion.•The corrosion rate of HRB400 in the micro-solution is much lower.•The reason for this difference is the anodic polarization in the micro-solution.•The micro-solution electrochemical method agreed well with the real site studies. An electrochemical method by submersing the HRB400 rebar specimen in simulated micro pore solution (47.125μL) is proposed to rapidly evaluate the corrosion rate of HRB400 in concrete. The results show that the corrosion rate of HRB400 in micro-solution is about five times lower than that in bulk solution. The reason for this difference is the anodic polarization caused by the higher concentration of dissolved iron ions in micro-solution. There is a small relational dispersed degree of corrosion rate measured by the optimized electrochemical cell in micro-solution and the real site studies.