Objective

To assess the strength of coarse aggregates used in the pavement components under gradually applied load and to determine the aggregates crushing value of the given sample of aggregates.

Apparatus used:

Crushing Machine, Tamping Rod, Trowel, Weighing Balance, Cylindrical Mould, Plunger etc.

 Take coarse aggregate in a pan and measure it to 3500g using the weighing balance.

 Arrange the sieves in the decreasing order of their size. Place the pan at the bottom and then add weighed quantity of coarse aggregate to the top most sieve and close the lid.

 Place the set of sieves in the mechanical shaker and allow to shake for 10 minutes.

 Collect the coarse aggregate retained on 10mm sieve in a separate container.

 Note down the weight of the empty cylinder as W₁(g). Then fill the cylinder with the aggregates retained on 10mm sieve in 3 layers.

Weight of empty cylinder (W₁) = _________g

 Note down the weight of the cylinder with the aggregates W₂(g).

Weight of cylinder with the aggregates (W₂) = _________g

 Cylinder is placed in position on base plate and plunger is placed so that it rests on level surface.

 Sample is placed in position on compression testing machine.

 Release the load and remove the cylinder from the setup.

 Sieve the material using 2.36mm IS sieve for 10 minutes and care must be taken to avoid loss of fines.

 Note down the weight of aggregate passing through 2.36mm sieve W₃(g).

Weight of aggregate passing through 2.36mm sieve (W₃)= _________g

 Observation and Results.

Since Aggregate Crushing Value above 35%, this aggregate would normally be regarded as weak aggregate.