Propagation Characteristics of Electromagnetic Waves in Concrete

摘要

This research develops models which can predict the velocity and attenuation of electromagnetic waves in concrete as a function of frequency, temperature, moisture content, chloride content and concrete mix constituents. These models have been proposed to predict the electromagnetic properties of concrete by aggregating the electromagnetic properties of its constituents. Water and the dissolved salt are the constituents having the most prominent effect on the dielectric behavior of concrete. A comparative study of three existing three-phase mixture models has been carried out. Numerical results have been generated using the most representative Discrete model . These results have shown that the real part of complex concrete permittivity (and therefore the velocity of electromagnetic waves) is independent of salinity or frequency in the 0.6 to 3.0 GHz frequency range. On the other hand, these results show that the attenuation coefficient and dielectric conductivity vary almost linearly with frequency in this same frequency range. The real part of concrete permittivity and the attenuation coefficient also show a linear dependence with respect to the degree of saturation of water in the concrete mixture. This suggests that future research should focus on approximating the complex models presented in this research by simple equations. (sdw)