Effect of Physical Properties of Granular Sustainable-Porous Materials on Water Content Measurements by Using a Low-Cost Sensor

Soil water content has a primary importance in several scientific fields involving the geotechnical, hydrological agronomic, ecological, and biological properties of the soil mass. In recent years, several techniques for the determination of soil water content in the laboratory and in situ have been proposed and developed. The application of these techniques and adopted measurement systems to different soil types is widely discussed in the literature, thus highlighting a nontrivial issue deserving further experimental research. This paper presents the results of the application to granular sustainable materials of a capacitive sensor originally developed for soil water content measurement. In particular, the application regards coffee ground samples with two grain size distributions prepared dry and at increasing water content in the range of 5 - 25 %, at different initial voids rations. The effect of initial voids ratio and grain size distribution is also examined.