08/26/2026
Why do we ask for a soil sample before performing field density testing?
The sample is used to perform a laboratory moisture–density relationship (Proctor) test, which establishes the soil's maximum density and optimum moisture content.
To perform this test, soil is compacted in a mold at various moisture contents. The resulting data provides laboratory reference values that are used during field compaction testing.
During field density testing, our technicians use the laboratory reference values along with a nuclear density gauge to calculate the percentage of compaction achieved in the field. The gauge measures in-place density and moisture content, and those results are compared to the Proctor test values to determine percent compaction.