Feasibility of Development of a Nuclear Density Gage for Determining the Density of Plastic Concrete at a Particular Stratum

摘要

Development of a nuclear density gage for determining the degree of consolidation of plastic concrete in selected horizontal layers was determined to be feasible. A commercially available, with some modifications, two-probe density gage (detector in one and source in the other) provided the most reliable laboratory results and is practical for field use. A single probe backscatter gage designed to measure a vertical dimension of plastic concrete demonstrated poor stability and considerable difficulty in calibration. A horizontal scanning technique, measuring the density vertically from pavement edge to pavement edge, was studied and determined to be impractical for use. Densities of plastic concrete were taken on seven construction projects using the two-probe technique. Results are included in the report.