Measurement of Sand Moisture From Weight and Capacitance

Moisture meters are widely used in various industries and environmental-related fields, and thus, the methods have been standardized. This article describes an instantaneous and absolute moisture measurement method for sand. The conventional absolute moisture meter heats a target material and measures the weight difference before and after heating and determines the moisture content. This method requires a heating process; therefore, it is time-consuming. Sand pulverized from the rock with an average density of 2.58 g/cm3 and an average relative dielectric constant of 5.50 were used to constitute the sand. Utilizing these known values, we propose an absolute moisture measurement method for sand from weight and capacitance. We constricted a measurement principle and a calibration method based on static electricity theory and verified the principle through experiments. From the dry state of sand, water is dispersed on the sand in increments of 5–40 cm3 and measured them. The measured values are evaluated through the ASTM evaluation for instruments. The repeatability was 1.21%. The limit of detection, limit of quantitation, linearity, and bias value were 0.22 cm3, 0.66 cm3, 0.28%, and 0.51 cm3, respectively, which are satisfactory.