Evaluation of electrical density gauge for field compaction control
Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Compacted soil is a vital element in the construction of any civil engineering project. Measurements of in-situ soil density and moisture content are commonly used in the residential, commercial, and transportation industries to control the process of soil compaction. Various methods currently exist to monitor compaction in soils for construction projects. The nuclear density gauge is currently the most commonly utilized test device for this purpose; however, there are strict regulations with respect to the handling, transport, and storage of this device because it contains radioactive material. A relatively new non-nuclear alternative is the electrical density gauge (EDG), which uses a series of electrical measurements in conjunction with calibrated soil models to infer in-situ soil density and moisture content. Two approaches currently exist for building soil models with the electrical density gauge: the first is calibration with in-situ measurements of density and water content provided by the nuclear density gauge, sand cone test, or an equivalent in-situ density test, and the second is calibration with "large mold" Proctor-type tests. In this study, both calibration methods were evaluated. Additionally, field compaction conditions were simulated in a "large" box where EDG tests and three common in-situ density tests (nuclear density gauge, sand cone, and drive cylinder) were performed to provide comparative results. In addition, the effect of temperature on EDG electrical measurements was explored using the "large-molds" and alternative temperature correction and calibration procedures were investigated as well. The findings from this study provide guidance for interpreting the results from future electrical density gauge studies, and are useful for engineers that may be considering the use of this technology for compaction control.