Method of determining moisture content in porous building materials using dielectric coefficient measurement

摘要

The method involves conveying a high frequency wave to the damp building material. The reflection wave reflected from the material is received and is determined with respect to its reflection factor relative to the conveyed wave. The reflection factor, the wave resistance of the waveguide system and the impedance of the probe are used to calculate the complex dielectric coefficient of the material. The dielectric coefficients are fed back to the weight or volume component moisture content of the material. The method involves making several measurements. The high frequency wave is conducted with a frequency f to a selected position of the material. The reflected wave is detected and its reflection factor is determined. The method involves determining the dielectric coefficients with the reflection factor and the known resistance of the system as well as the impedance of the probe. In modelling the probe a parallel conduction value is connected to the empty run capacitance. Changes in the latter and the parallel value are taken into consideration in dependence on the frequency and the dielectric coefficient of the existing medium.