AGGREGATE CRUSHING VALUE

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Apparatus Required

Aggregate sample shall consists of particles passing on 12.5mm Sieve and retained on 10mm sieve.
The aggregate shall be in saturated surface dry condition.
Fill the cylindrical measure in three layers of approximately equal depth , each layer being tamped 25 times with the rounded end of tamping rod and finally levelled off , This weight of the material is to be determined and the same weight of the sample shall be taken for repeat test.
The cylinder of the test apparatus shall be put in position to the base plate & the test sample be added in thirds, each part being subjects to 25 strokes from the tamping rod .the surface of the plunger shall be carefully levelled, the plunger inserted so that it rests horizontally on this surface.
The apparatus with the test sample and the plunger in position shall then be placed between the platens of the test machine and loaded at a fairly uniform rate so that the total load of 400 KN reached in 10 minutes.
The load shall be released and the whole of the material removed from the cylinder and sieved on a 2.36mm IS sieve. The fraction retained on the sieve shall be weighed.
Repeat the whole procedure for another set.
The aggregate crushing value then calculated by dividing the weight passing on 2.36mm sieve with the whole sample weight in cylinder taken for test .