Methodology for Determination of Hygroscopic Moisture Content of Soils

Abstract

Hygroscopic moisture content of the soil is usually determined by an air-drying method and has been related with the surface area and cation exchange capacity of the soil, by many researchers. However, as relative humidity influences the overall soil-water interaction, quantification of its impact on hygroscopic moisture content of the soil becomes mandatory. Incidentally, it has been noted that no standard methodology, which specifies determination of the soil hygroscopic moisture content exists in the literature. With this in view, laboratory investigations were carried out on soils, with entirely different properties, and by exposing them to different relative humidity and storage time. Based on the results, “optimal hygroscopic moisture content” of the soil has been defined and the methodology for its measurement has been proposed. Further, attempts were made to correlate hygroscopic moisture content of the soil with its surface area, cation exchange capacity, liquid limit, swelling potential, and electrical properties conductivity and dielectric constant . Such correlations will be of the utmost help in predicting these properties of the soil by knowing its hygroscopic moisture content.