Electromagnetic properties of mortars over a broad frequency range and different curing times

Abstract

A large dielectric measurement cell, with 54 ml sample volume, was designed and calibrated to operate over a 1 MHz-3 GHz frequency range. The cell was used to measure the dielectric constants and conductivities of concretes over a broad frequency range and different curing times. The water/cement/sand ratios of the concrete were changed to study the dependence of the electromagnetic properties on them. Chemical admixtures to retard and accelerate the curing process of concretes were also added. It was found that the electromagnetic properties of concretes vary significantly over the frequencies. Furthermore, during the curing process, the water/cement/sand ratios and chemical admixtures of concretes affected their electromagnetic properties. A relationship of the electromagnetic properties of concretes to their various physical states and constituent components could be used for the quality control of concretes in construction work. © 1991 Chapman and Hall Ltd.