Sieve analysis

A sieve analysis (or gradation test) is a practice or procedure used in geology, civil engineering, and chemical engineering to assess the particle size distribution (also called gradation) of a granular material by allowing the material to pass through a series of sieves of progressively smaller mesh size and weighing the amount of material that is stopped by each sieve as a fraction of the whole mass.

The size distribution is often of critical importance to the way the material performs in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sand, crushed rock, clay, granite, feldspar, coal, soil, a wide range of manufactured powder, grain and seeds, down to a minimum size depending on the exact method. Being such a simple technique of particle sizing, it is probably the most common.

Procedure

A gradation test is performed on a sample of aggregate in a laboratory. A typical sieve analysis uses a column of sieves with wire mesh screens of graded mesh size.

A representative weighed sample is poured into the top sieve which has the largest screen openings. Each lower sieve in the column has smaller openings than the one above. At the base is a pan, called the receiver.

The column is typically placed in a mechanical shaker, which shakes the column, usually for a set period, to facilitate exposing all of the material to the screen openings so that particles small enough to fit through the holes can fall through to the next layer.