Initial Review of Rapid Moisture Measurement for Roadway Base and Subgrade
Stephen Sebesta, Jeongho Oh, Sang Ick Lee, Marcelo Sanchez, and Ross Taylor, May 2013
This project searched available moisture-measurement technologies using gravimetric, dielectric, electrical conductivity, and suction-based methods, as potential replacements for the nuclear gauge to provide rapid moisture measurement on field construction projects. Such testing is critical for acceptance of field compaction, and could become more critical as states look toward mechanistic-based acceptance. The first phase of this project, presented in this report, carried out test method development, pilot testing, and then initial deployment of the most promising devices. These activities confirmed the utility of existing direct heat and microwave oven tests, revealed promising results with an electrical-impedance based field test, and resulted in draft test procedure development with a portable dielectric-based device and a moisture analyzer. Several procedures evaluated only test the passing No. 4 fraction; reliably predicting the moisture content on the full gradation from the passing No. 4 measurement remains a topic needing further investigation. Future work on this project will deploy the most promising devices on a number of construction projects representing a spectrum of materials, where the devices will be evaluated for bias, precision, and sensitivity. Additionally, this project identified and pilot tested a microwave resonance-based device that may enable rapid field moisture measurement with a high level of testing coverage. Future work on this project will continue development work with applying this device to windrows and processed construction materials.
Keywords: Moisture Content, Moisture Measurement, Water Content, Rapid, Soil Density Gauge, Electrical Density Gauge, Nuclear Gauge, DOT 600, SDG, EDG, Microwave, Direct Heat, Moisture Analyzer
ENTIRE REPORT (Adobe Acrobat File – 3.5 MB)