R. R. Proctor developed a laboratory test procedure for determining optimum moisture content at which the dry density of soil mass become the maximum. This procedure was developed in 1933 and named after R.R. Proctor as Proctor Test.

Later, for heavier loading condition proctor test was modified which become popular as modified Proctor Test.

Now a days both of the test procedure are widely used laboratory test  for compaction determining for any specific soil type.

### Proctor Test

• Cylindrical metal mould of 4 inch inner dia, 4.6 inch height and volume=1/30 cft with detachable collar and base plate of known weight.
• 3Kg air dried sample soil passing through 4.75 mm sieve, add small(4-10%) quantity of water and mix throughly, covered with moist cloth for a mature time of 15-30 minutes. The sample soil to be collected from site.
• Ramming with a rammer of 5.5 lb weight,25 blows at each of three  layer with a fall height of 12 inch.
• Find out Bulk Density, Y=W/V (lb/cft),% of water content and corresponding dry density Yd=Y/(1+W), lb/cft
• Repeat test successively adding more and more water. Plot in graph paper(% water content) in X-axis and corresponding dry density in the Y- axis in order to  find out optimum water content and maximum dry density.

### Modified Proctor Test

• Cylindrical metal mould of 4 inch inner dia, 4.6 inch height and volume=1/30 cft with detachable collar and base plate of known weight.
• 3Kg air dried sample soil passing through 4.75 mm sieve, add small(4-10%) quantity of water and mix throughly, covered with moist cloth for a mature time of 15-30 minutes. The sample soil to be collected from site.
• Ramming with a rammer of 10 lb weight,25 blows at each of five  layer with a fall height of 12 inch.
• Find out Bulk Density, Y=W/V (lb/cft),% of water content and corresponding dry density Yd=Y/(1+W), lb/cft
• Repeat test successively adding more and more water. Plot in graph paper(% water content) in X-axis and corresponding dry density in the Y- axis in order to  find out optimum water content and maximum dry density.