Use of frequency power law to link the results of two EM testing methods for the characterization of humid concretes

Abstract

This paper deals with the EM characterization of hydraulic concrete for different water contents over a large frequency band. Two measurement methods are used: the capacitive technique and an EM coaxial cell. The aims of this paper are (1) to fit the dispersion curve of the complex permittivity obtained by the coaxial cell in order to extrapolate it on a larger frequency band and (2) to compare the model and experimental results at a frequency of 33 MHz. For the first step, fitting and extrapolation are performed by using the Jonscher's model with 4 parameters, which are validated with data from literature. Then in a second step, they are applied on dispersion curves which we measured on 6 different concrete mixes, at 4 different water contents. Finally, the experimental results obtained by the capacitive technique are analyzed and compared to the real part of the fitted complex permittivity at 33 MHz.