Moisture Content Test of Glass Fill Using a Nuclear Densometer

Issue: The moisture content of a fill material will affect its compaction characteristics and needs to be evaluated during quality control of the fill operation. When the fill is drier than its optimum moisture content, any moisture in the fill serves as a lubricant and helps the relative movement of the particles when densifying under vibratory compaction. When the fill is wetter than its optimum moisture content, the moisture absorbs part of the compaction energy and prevents the formation of a denser material. Hence, moisture content determination constitutes an important part of quality control because the information is used in evaluating the compaction efficiency and material behaviors. Accurate assessment of the moisture content of a fill material is important also because the density requirement of fill is based on the dry density of the material, and the dry density is calculated based on the measurements of wet density corrected for moisture content.