Time domain reflectometry to monitor in-situ drying behavior of calcium sulfate foam

The calcium sulfate foam (SULFOAM) building material was developed during a research project and needed to be characterized regarding to its in-situ drying behavior. For this reason, the dielectric properties in dependence of volumetric water content have been determined between 50 MHz and 5 GHz with coaxial cell measurement method. After this, a time domain reflectometry (TDR) measurement setup was developed and integrated in three different test walls. From this data permittivity and volumetric water content of SULFOAM are calculated via different approaches and related to the frequency spectra. Finally, it will be shown that spatial changes along the sensor cable make moisture transfer and drying behavior visible. The measurements helped to understand the material behavior for different use cases and provided the skilled in the art with a valid tool for the assessment of the material.