Experimental Comparative Study on Devices Measuring Field Moisture Content of Roadbed Materials

For in-place moisture content measurements as a part of quality control (QC) of roadbed construction, many agencies rely on nuclear testing and physical gravimetric drying for moisture content measurements. In this study, alternative methods were initially evaluated to identify technologies that could be used to measure moisture content in the field substitute using gravimetric, dielectric, and electrical conductivity, and suction-based methods. The small scale field test and actual field tests were then performed to evaluate device bias and accuracy, and estimates of single-operator standard deviation of repeat measurements. Through those results, the list of most promising devices could be narrowed down.