Apparatus :
-A steel cylinder 15 cm diameter with plunger and base plate.
-A straight metal tamping rod 16mm diameter and 45 to 60cm long rounded at one end.
-A balance of capacity 3 kg readable and accurate to one gram.
-IS sieves of sizes 12.5mm, 10mm and 2.36mm
-A compression testing machine.
-Cylindrical metal measure of sufficient rigidity to retain its from under rough usage and of 11.5cm diameter and 18cm height.
-Dial gauge
Sampling of Aggregates :
-Coarse aggregate passing 12.5mm IS sieve and retained on a10mm IS sieve are selected and heated at 100 to 110°C for 4 hours and cooled to room temperature.
Procedure of Aggregate Crushing Value Test :
-Put the cylinder in position on the base plate and weigh it (W).
-Put the sample in 3 layers, each layer being subjected to 25 strokes using the tamping rod. Care being taken in the case of weak materials not to break the particles and weigh it (W1).
-Level the surface of aggregate carefully and insert the plunger so that it rests horizontally on the surface. Care being taken to ensure that the plunger does not jam in the cylinder.
-Place the cylinder with plunger on the loading platform of the compression testing machine.
-Apply load at a uniform rate so that a total load of 40T is applied in 10 minutes.
-Release the load and remove the material from the cylinder.
-Sieve the material with 2.36mm IS sieve, care being taken to avoid loss of fines.
-Weigh the fraction passing through the IS sieve (W2).
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