Equivalent circuit model for AC electrochemical impedance spectroscopy of concrete

Abstract

An equivalent circuit model for AC electrochemical impedance spectroscopy (EIS) of concrete has been proposed, which contains parameters RCCP, the resistance of the continuously connected micro-pores in the concrete; RCP, the resistance of the discontinuously connected micro-pores, blocked by cement paste layers in the concrete; Cmat, the capacitance across the concrete matrix; and CDP, the capacitance of the cement paste layers blocking the discontinuously connected micro-pores in the concrete. The proposed model can successfully explain the experimental phenomena observed by other researchers, such as the emergence of the capacitive loops in high-frequency range, the influences of hydration time, silica fume, water/cement ratio on the loops, etc.