Validation Tests of a Non-Nuclear Combined Asphalt and Soil Density Gauge

Researchers at ERDC evaluated the Soil Density Gauge SDG and the Combined Asphalt Soil Evaluator CASE both of TransTech Systems as suitable non-nuclear replacements to the nuclear density gauge NDG in a series of full scale test sections. One-to-one comparisons of soil dry density and moisture content were made between the NDG, SDG and CASE over four unique soil types of varying density and moisture content. The SDG and CASE were tested both calibrated and uncalibrated to establish suitable field preparation. A similar comparison of asphalt density was conducted between the NDG and the CASE on both warm mix and hot mix asphalt at varying surface temperatures. Test results concluded that the CASE unit was the most suitable replacement device however both the SDG and CASE require field calibration from a secondary density technique to be effective. In soil, the SDG and CASE are recommended only for contingency construction activities, because each lacks sufficient accuracy for quality control use in permanent facilities. For asphalt, the CASE is recommended only as a substitute to the NDG for establishing compaction patterns in asphalt so long as it is calibrated to a core density sample for each unique asphalt mixture.