Oven-Drying Characteristics of Soils of Different Origins

Abstract

The accurate measurement of the moisture content of a soil is an important step in characterizing its engineering behavior. However, the oven-drying method can cause some chemical reaction (oxidation or loss of water of crystallization) to occur in certain soil types. The level of oxidation of the solid particles was studied over the drying temperature range of 60 to 140°C for different soils. The period of oven drying necessary for the specimen mass to equilibrate was also examined. The standard practice of oven drying the soil specimens at 110 ± 5°C or 105±5°C over a period of 24 h was confirmed as giving accurate moisture content values for inorganic soils. Oven drying of peat and other highly organic soils over a period of 24 h at 80°C produced similar levels of accuracy in the moisture content measurements as that for inorganic soils at the standard oven drying temperatures of 105 or 110°C. Some oxidation of the organic fraction commenced at between 80 and 90°C.