Moisture content monitoring of construction materials: from in-line production through on-site applications

In this work, a time domain reflectometry (TDR)-based system for measuring water content of construction materials is presented. The proposed system relies on the fact that the presence of water leads to an increase of the effective dielectric permittivity of materials (being the relative dielectric permittivity of construction materials in the order of 3-7, and that of water approximately 78). Therefore, through TDR measurements of the apparent permittivity of the material, it is possible to obtain calibration curves that allow retrieving the water content. Starting from these considerations, in this paper, the results related to moisture content measurements of three construction materials (namely, plaster mortar, portland cement and pozzolan cement) are reported. The advantage of the proposed system is that it can allow to monitor in real time the water content of construction materials inline, so as to assess their quality throughout the production process.