Considerations for Potential Use of Nuclear DensityGages on Concrete

Abstract

The principal purpose of this study is to decide if the potential use of nuclear density gages to estimate concrete density might produce results worthy of accurate engineering interpretation. As such, it was important to verify the degree to which the proportions of mix components affect the interrelationship of density, air content, and compressive strength of concrete in order to establish lish the precision of concrete density estimate required to determine in situ air content or predict potential compressive strength. Once this required precision was found it was compared briefly with the precision to be expected of standard industry nuclear density gages. An extensive testing program was carried out that covered a wide range of water-cement ratios w/c and aggregate-cement ratios a/c. Results indicate that if a nuclear density gage can measure the density of concrete to within plus or minus 1% (a value that such a device should be capable of), then the air content and compressive strength of that concrete can be estimated to within an acceptable range.