Nuclear density gauge compaction testing alternatives: synthesis and critical analysis

Abstract

The costs of training, licensing and security for agencies using the nuclear density gauge (NDG) have become increasingly onerous for public engineering agencies, leading them to seek less expensive alternatives to conduct compaction testing. The study focused on three comparators: difference in approaches between tested devices and methods, the setting of targets for modulus stiffness devices and the examination of reported accuracy and reliability. This paper’s objective is to summarize the reported results for each alternative and provide the details of the findings. The paper finds that previous research has been almost exclusively focused on laboratory testing and is nearly devoid of authoritative information on field test performance parameters such as repeatability and time to complete a field test. It concludes that research is needed that includes a broad set of testing methods and equipment on the same set of soil conditions. The paper’s primary contribution is to consolidate and critically analyze the results of the current compaction testing research and benchmark the state-of-the-practice in field compaction testing. This paper does provide comparisons without intent to identify a “best” alternative because each device is adapted to specific soil conditions. Testing agencies may require differing devices based on budget, manpower and training.