Monitoring Hydration of Alkali-Activated Slag and Fly Ash

This paper presents developments in electrical impedance methods to study hydration and reaction kinetics of alkali activated slags and fly ash at room temperature (i.e. 21 degrees C). To highlight the testing methodology, work focuses on monitoring the temporal change in both conductance and capacitance of a typical slag and low-lime fly ash activated with calcium hydroxide. It is also shown that the measured electrical parameters change markedly with frequency of applied electrical field. The latter was found particularly relevant to capacitance measurements.