Test: Sieve Analysis - Civil Engineering (CE) MCQ

According to IS 565, the sieve sets are 80mm, 40mm, 20mm, 10mm, 4.75mm for coarse aggregates.

At the base of all the sieve sets, round pan is placed to collect the particles finer than the last sieve size. It is called the receiver.

The 5 methods are throw-action, horizontal, tapping, wet and air circular jet.

The shape of particles is assumed to be nearly round or spherical so that they pass through the square opening. For elongated, flaky particles it will be difficult.

As per IS code 2720 Part 4. Mechanical vibrator is switched on and allowed to vibrate for 15-20 minutes. It ensures proper grading of particles.

Only if the sample is placed on largest sieve size, it can be sorted, according to each smaller sieve size below.

The percentage retained is calculated by dividing weight of sample retained by the weight of the total sample, taken in beginning of test.

Sometimes samples contain very fine powders which tend to agglomerate. In dry sieve analysis, it would lead to clogging of meshes and it makes analysis difficult.

A graph is plotted after performing sieve analysis. It shows different curves. A narrow gradation is also called uniform gradation. It shows that the aggregate is of approximately the same size.

IS 2720 gives the specifications. It requires using sample weighing 5 kg for coarse aggregates and 1 kg for fine aggregates.