Compaction Test is used to determine the relationship between dry density and water content of soil. Soil is compacted in a standard mould using a rammer. Different water contents are tried to find the best compaction condition. The test gives: Maximum Dry Density (MDD) → highest density soil can achieve Optimum Moisture Content (OMC) → water content at which MDD occurs Two Methods: IS 2720 Part 7 → Standard Proctor Test IS 2720 Part 8 → Modified Proctor Test (higher compaction energy) Procedure (Basic Idea) Take soil sample and add water in steps Compact soil in mould in layers using rammer Measure weight and calculate dry density Plot graph between Dry Density vs Water Content Peak point gives MDD & OMC Applications Road & pavement construction Embankment & dam construction Foundation soil preparation Earthwork quality control Field compaction specification