A new approach to time-resolved electrochemical impedance spectroscopy using the Impedance Camera to track fast hydration processes in cement-based materials

In this paper, usefulness and accuracy of the new Impedance Camera working in the time-resolved electro-chemical impedance spectroscopy (TR-EIS) mode was demonstrated. Flash setting monophase hydraulic binder material Ca7ZrAl6O18 (C7A3Z), and traditional both Ordinary Portland Cement (OPC) and calcium aluminate cement (CAC)-based alumina spinel castables (CMAS castables) were selected and evaluated. The TR-EIS mea-surements were conducted in the frequency range from 100 Hz to 1 MHz with 17 point per decade. TR-EIS results were correlated with the hydration heat release determined by calorimetry, and thermal behavior (DSC-TG-EGA (MS)) and phase composition (XRD) of the C7A3Z cement paste. In this work, a new approach to divide the curve of speed impedance changes into few characteristic periods of hydration, different than presented so far as the periods on the heat flow curve obtained by isothermal calorimetry was implemented.