Maximum dry density, optimum moisture content
A soil at a selected water content is placed in five layers into a mold of given dimensions, with each layer compacted by 25 or 56 blows of a 10-lbf (44.5-N) rammer dropped from a distance of 18-in. (457-mm), subjecting the solid to a total compactive effort of about 56,000 ft - lbf/ft3 (2700kN-m/m3). The resulting dry unit weight is determined. The procedure is repeated for a sufficient number of water contents to establish a relationship between the dry unit weight and the water content for the soil. This data, when plotted, represent a curvilinear relationship known as the compaction curve. The values of optimum water content and modified maximum dry unit weight are determined from the compaction curve.
2300 - 5600 grams
Compaction, density, modified effort, modified Proctor test, moisture-density curves, soil compaction, Proctor