What is astm d-698?

ASTM D-698 is a standard test method for determining the maximum dry density and optimum moisture content of soil and aggregate mixtures using a 5.5 lb hammer and a 12 in. drop. It is commonly used in geotechnical engineering and construction projects to evaluate the compaction characteristics of soil and aggregates for highway construction, foundations, and embankments.

The test involves compacting a sample of soil or aggregate at different moisture contents into a cylindrical mold with three layers and measuring the weight and volume of the compacted sample. The maximum dry density and optimum moisture content are determined by plotting a graph of the test results and determining the peak of the curve. The results of the test can be used to determine the compaction requirements for a specific project and to monitor the construction process to ensure that desired compaction levels are achieved.

ASTM D-698 was first adopted in 1957 and has since been revised several times to improve the accuracy of the test method. The most recent revision was in 2017.