Soil compaction control testing for earthworks in Civil Construction undertaken by Site Geotechnical, includes field density testing using a nuclear density guage. It is used to determine the dry and/or wet density and moisture content of the material being tested. The Field Density is usually compared with a laboratory compaction test of the same material type, to produce a ratio between field and laboratory compaction referred to a Hilf Density Ratio and Dry Density Ratio.
The degree of compaction specified and achieved in cohesive soils is usually expressed as a density ratio, as described in AS 1218.104.22.168. This compares the density of the compacted soil with a reference density, being the peak density, which can be achieved in a controlled laboratory compaction process, e.g. Standard Compaction, AS 1222.214.171.124. Density Ratio is also sometimes referred to as Relative Compaction. This more generic term allows for other reference testing procedures such as Hilf Rapid Compaction (AS 12126.96.36.199) for clay fills.