Dry density using Proctor apparatus
Ref : IS 2720 (part VII), IS 9198
Purpose : To find out moisture - density relationship of soil.
Salient features of apparatus:
Mould for compaction:
Diameter - 100mm
Height - 127.3mm
Diameter - 50mm
Length - 310mm
Weight - 2.60 Kg ± 25 g (light)
4.90 Kg ± 50 g (heavy)
Weigh 5 Kg of air dried soil sample.
Add 10 % water less than estimated optimum moisture content (O.M.C) to the soil.
Keep in air tight container for 16 hours.
Fill the soil in mould in three layers.
Each layer should be compacted with 25 blows with the help of rammer dropped from height 310mm (light) / 450mm (heavy).
Remove the collar and trim off the surplus soil.
Weigh the mould and calculate the bulk density.
Repeat the procedure with addition of 2% more water up to the estimated value of O.M.C.
Calculate dry density and draw a curve showing the relationship between moisture content and dry density.
Mark the points of maximum dry density (M.D.D) and O.M.C on the curve.