Frequency domain reflectometry in the determination of dielectric constant of bentonite

Abstract

This work presents the determination of the humidity and the dielectric constant of bentonite using a probe based on the frequency domain reflectometry (FDR) method. The basic principle of the probe used in this study is the measurement of the refractive index of the soil √ε at 100 MHz to allow the determination of the humidity through a known relation between these quantities. The value of 0.99 for the correlation coefficient obtained in this study demonstrated an accurate relationship between the humidity and the dielectric constant of bentonite. Also in this study the humidity of the bentonite using the FDR method was compared to the values obtained using the calcium carbide method.