CIRCUIT MODELS FOR CEMENT BASED MATERIALS OBTAINED FROM IMPEDANCE SPECTROSCOPY

The AC electrical properties of a typical mortar specimen have been measured at two different humidity stages over a frequency range as large as 10(-3)-10(7) Hz. The AC electrical behavior at these humidity stages is interpreted in terms of two equivalent circuits with a difference between the bulk DC resistances of about 6 orders of magnitude. On the basis of these circuits four fundamental conductivity processes were identified.