What information is provided through laboratory compaction tests?

Laboratory compaction tests primarily focus on determining the relationship between moisture content and the density of soil. The results of these tests, such as Proctor tests, yield vital information, including the optimum moisture content required to achieve maximum dry density of the soil. This information is crucial for construction and engineering applications where soil stabilization and compaction are implemented to ensure the structural integrity of the built environment.

Through these tests, the percent compaction can be derived by comparing the achieved density to the maximum dry density at the optimum moisture content identified during the test. Furthermore, knowing the molding water (moisture content) needed allows engineers to select appropriate moisture levels for soil before compaction in the field. This aids in achieving the desired soil properties for construction purposes, making it critical information for ensuring the soil behaves as expected under load.

Other options provide limited or incorrect information: soil type and density do not provide insight into the compaction process, and grain size distribution does focus on different soil characteristics than those assessed in compaction tests, which are centered on density and moisture content relationships.