Computer as a tool for controlling measurement of water content in building materials

This paper describes the application of wireless LC sensor for measuring the concentration of water (or moisture) in the building materials. The sensor has manufactured on a double layered PCB (Printed Circuit Board) and placed in a test sample of a building material that is immersed in water. The change of water concentration in the sample can be measured wirelessly (antenna coil) by monitoring variations in sensors resonant frequency. Clay brick and aerated autoclaved concrete block are used for examination and testing as the often used building materials. Dielectric constant of water is much higher compared to the dielectric constant of test samples, and the higher concentration of water (or moisture) content of samples dictated a reduction in the sensor resonant frequency. Measurements were done at room temperature, using a PC with in-house developed software and an Impedance Analyzer HP-4194A. The program has been developed in LabVIEW software package allowing remote control and acquisition of measured data.