Standard Proctor Compaction Test is used to determine the maximum dry unit weight of compaction for soils. This test is carried out accordance to BS 1377 : Part 4 :1990. During earthwork stage of construction, compaction of soils is necessary to improve its strength. Proctor (1933) developed this Standard Proctor Compaction Test for determination of maximum dry density for soils which can be used for specification of field compaction.
Soil sample would be collected from site and sieved to determine which type of Compaction Test is suitable. During the compaction test, the soil sample is compacted in mould by using a rammer. For Standard Proctor test, this step is carried out using a 2.5kg ram and soil is compacted in 3 equal layers while for Modified Standard Proctor test, this step is carried out using a 4.5kb ram and soil is compacted in 5 equal layers. This step will be repeated few times with a different moisture content added to obtain a series of data
The dry densities obtained in a series of determinations shall be plotted versus moisture contents, W. A smooth curve shall be drawn through the resulting points and the position of the maximum on this curve with the corresponding moisture content shall be determined.
The dry density corresponding to the maximum point on the moisture content versus dry density curve shall be reported as the maximum dry density.