Moisture content is an essential property of geomaterials that should be monitored during construction of pavement layer systems. Proper estimation of moisture content is crucial in quality control/quality assurance (QC/QA) of pavement construction. Several field and laboratory devices are available for measuring geomaterial's moisture content. However, these methods require different testing and calibration procedures for quantifying different types of soils. A number of moisture devices including Soil Density Gauge (SDG), Speedy Moisture Tester (SMT) and Time Domain Refiectometer (TDR) were evaluated using four different geomaterials. The tests were repeated several times at different moisture levels (from dry to wet of optimum moisture contents) after compaction of large-scale laboratory samples. The oven dried moisture content was used as a baseline to compare with the results of the devices. The bias and linearity of the devices were then preliminarily determined. Equipment-related variability of each device was also evaluated through statistical analyses. The performance of the SDG is material dependent while SMT results seem to exhibit less variation in determining different levels of moisture contents. With rigorous calibration, the TDR probes provided reliable results. Inspecting the raw data it seems that the reported moisture contents with the SDG can be improved through a more rigid calibration such as those recommended for the TDR.
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