MODIFIED PROCTOR COMPACTION TESTOR HEAVY COMPACTION TEST (IS-2720PART-8) Objective To determine moisture content and dry density relationship using heavy compaction or modified compaction method as per IS-2720-Part-8. Apparatus • Metal mould (volume = 1000 cm3) • Balance (capacity = 10 kg, least count = 1g) • Oven (105 to 1100C) • Sieve (19 mm) • Metal rammer (weight = 4.9 kg) Compaction Mould and Rammer Procedure 1. Dry the soil sample by exposing it to air or sun light. 2. Sieve the air dried soil through 19 mm sieve. 3. Add suitable amount of water with the soil and mix it thoroughly. For sandy and gravelly soil add 3% to 5% of water. For cohesive soil the amount of water to be added should be 12% to 16% below the plastic limit. remove the extension collar and level carefully the top of the mould by means of straightedge. Compact the moist soil into the mould in five layers of approximately equal mass. with the help of 4. and the moisture contents should be such that the optimum moisture content. 10.e. After weighing remove the compacted soil from the mould and place it on the mixing tray. Record the moisture content as ‘M’. Broken up the remainder of the specimen and repeat step 5 to step 9 by adding suitable increment of water to the soil. For cohesive soils the increment in general is2% to 4%. After completion of the compaction operation. 6. γd in g/cm3 of each compacted specimen is calculated from the following equation. each layer being given 25 blows. Determine the water content of a representative sample of the specimen. of determinations made shall be at least five. γb in g/cm3 of each compacted specimen is calculated from the following equation. is within that range. 1000 cm3.9 kg rammer. 11.4. at which the maximum dry density occurs. Calculation Bulk density. Weigh the mould with the compacted soil to the nearest 1 g. For sandy and gravelly soils the increment in general is 1% to 2%. W1 = Weight in g of mould + base plate W2 = Weight in g of mould + base plate + soil Vm = Volume of mould i. Dry density. Attach the extension collar with the mould. 7. Record this weight as ‘W2’. γd = 100 γb/(100+M) . Record this weight as ‘W1’. Weigh the mould with base plate attached to the nearest 1g. dropped from a height of 450 mm above the soil. The total no. 9. The blows must be distributed uniformly over the surface of each layer. 5. γb = (W2-W1)/Vm where. 8. A smooth curve is then drawn through the resulting points and the position of the maximum on this curve is determined.C.org/2014/06/14/modified-proctor-compaction-test-or-heavy-compaction-test-is2720-part-8/ .).M.D). which is called maximum dry density (M. γd . M = Moisture content of soil Graph The dry densities. γb = Bulkdensity of soil in g/cm3. obtained in a series of determinations is plotted against the corresponding moisture content ‘M’.Where. Reference from http://civilblog. And the corresponding moisture content is called optimum moisture content (O.D.
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