Evaluation of Nonnuclear Soil Moisture and Density Devices for Field Quality Control

Abstract

When new transportation infrastructure is constructed or current infrastructure systems undergo maintenance, sufficient soil strength is critical to a successful construction effort. Currently, soil design specifications are given for a minimum soil density and a specified range of soil moisture content. Quality control is achieved by monitoring the soil density and moisture content throughout the construction process. The nuclear density gauge (NDG) is most commonly employed to determine soil density and moisture content because of its ease of use, speed of readings, and reliability of results. However, potential safety hazards and rigorous user certification requirements have led many agencies to seek alternative devices. This paper focuses on a portion of a much larger study that compared a wide range of compaction control devices; the paper also assesses the performance of devices that measure soil density and moisture content. Several new, commercially available alternatives for the measurement of soil density were tested on various soil types and conditions to determine which device performed best and most consistently. For the same soil types and conditions, several devices and techniques for the determination of soil moisture content were also tested. The combination of the TransTech soil density gauge and the heated frying pan–open flame field moisture content techniques represented the best alternative to the NDG.