By | November 19, 2017


The object of the experiment is to determine the compaction characteristics of given soil.



The dry density γd is given by the following relation,

γd = γ/1 + ω

where, γ = Bulk density of soil ; ω = Moisture content of soil



1. Proctor’s standard equipment consisting of

(a) Proctor’s mould

(b) Hammer

2. Electric oven

3. Balance

4. Sieve 4.75 mm

5. Steel spatula



1. About 2.5 kg of loose soil passing through 4.75 mm sieve, is taken.

2. The empty proctor mould is weighed in the platform balance.

3. The proctor mould is filled with the soil in three layers, each layer being compacted by 25 blows of the standard rammer of 2.6 kg dropped from a height of 31 cm above the soil. After compacting the second layer the mould is fitted with a detachable collar for compaction of third layer. The compacted layer is then finished to a level surface just at the rim of the mould itself.

4. The mould with this soil is weighed is the platform balance. The bulk density of the soil is calculated.

5. A small amount of the compacted soil is taken in a container of known weight for determination of moisture content.

6. The dry density is calculated from the bulk density and moisture content as obtained in steps 4 and 5 respectively.

7. Steps 3 to 6 are repeated with increasing moisture content of the soil.

8. Moisture content of soil is increased by adding water 2 – 5 % by weight of dry soil each time. Bulk density of contacted soil will increase initially with the increase in moisture content. After certain moisture content bulk density will decrease. The test is repeated till a decreasing trend in bulk density is observed.

9. From the data as obtained from the tests mentioned above moisture content vs. dry density curve is plotted for the soil. From the curve, optimum moisture content and maximum dry density are determined.



1. Details of the proctor mould :

(a) Height = ……….

(b) Diameter = ……….

(c) Volume = ……….

(d) Weight = …………

2. Dry density and moisture content : ……………

Observation No.


2 3 4


Weight of mould + compacted soil (kg)          
Weight of compacted soil (kg)          
Bulk Density (kg/cm3)          
Can No.          
Weight of empty can (W1) (gm)          
Weight of can + wet soil (W2) (gm)          
Weight of can + dry soil (W3) (gm)          
Moisture content, ω (%) = {(W2 – W3)/(W3 – W1)} x 100          
Dry Density, γd = γ/1 + ω          



Plot dry density vs moisture content.

From the curve, find optimum moisture content and maximum dry density.



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