Development of a method for obtaining Nyquist plots identical to those of the three-electrode AC impedance method in concrete-embedded rebar without requiring electrical continuity

Abstract Corrosion of steel bars is one cause deterioration in reinforced concrete structures. The state corrosion rebar structures can be measured using the AC impedance method. typical three-electrode method requires electrical continuity between and measurement device, which may inconvenient because structure to partly damaged by processes such as drilling. present study proposes a obtain same spectra modifying electrode configuration four-electrode procedures for are follows: first, place counter reference at point; another sufficient distance from both point applied electrode; connect WE_I electrode, WE_V CE RE measure impedance. In this paper, physical experiments numerical demonstrate validity above Under conditions experiment (concrete W/C = 54.2%, cover 50 mm), application was required about 1.3 m. matching also Graphical abstract