Investigation of the Nuclear Gauge Density Calibration Method

Abstract

ABSTRACT Nuclear gauges have been used in the compaction control of pavement construction since 1950s. The accuracy of nuclear testing significantly relies on the calibration of nuclear gauges, which establishes the correlation between material density and nuclear gauge count reading in the form of a calibration equation with several constants. The choice of a calibration equation not only changes with engineering conditions and requirements, but also depends on the physical principals of measurement. This paper investigates several forms of calibration equations. Numerical analysis is conducted to show the capabilities of different calibration equations using the existing experimental results. Although the exponential equation with three constants is favourable due to its physical soundness, it does not consistently provide the best agreement with experiments. To reach a higher accuracy, a modified four-standard-block calibration method is proposed. The advantage of this method is demonstrated with the experimental data.