A sieve analysis (or gradation test) is a practice or procedure used in geology, civil engineering,[1] and chemical engineering[2] 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.

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.

A representative weighed sample is poured into the top sieve which has the largest screen openings.

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.

The results of this test are provided in graphical form to identify the type of gradation of the aggregate.

The complete procedure for this test is outlined in the American Society for Testing and Materials (ASTM) C 136[4] and the American Association of State Highway and Transportation Officials (AASHTO) T 27[5] A suitable sieve size for the aggregate underneath the nest of sieves to collect the aggregate that passes through the smallest.

The entire nest is then agitated, and the material whose diameter is smaller than the mesh opening pass through the sieves.

After the aggregate reaches the pan, the amount of material retained in each sieve is then weighed.

[6] In order to perform the test, a sufficient sample of the aggregate must be obtained from the source.

To prepare the sample, the aggregate should be mixed thoroughly and be reduced to a suitable size for testing.

[6] The results are presented in a graph of percent passing versus the sieve size.

In the air they carry out free rotations and interact with the openings in the mesh of the sieve when they fall back.

Amplitude and sieving time are set digitally and are continuously observed by an integrated control-unit.

Therefore, sieving results are reproducible and precise (an important precondition for a significant analysis).

Horizontal sieve shakers are preferably used for needle-shaped, flat, long or fibrous samples, as their horizontal orientation means that only a few disoriented particles enter the mesh and the sieve is not blocked so quickly.

When it comes to wet sieving it is very important not to change the sample in its volume (no swelling, dissolving or reaction with the liquid).

When passing the narrow slit of the nozzle the air stream is accelerated and blown against the sieve mesh, dispersing the particles.

Sieve analysis has, in general, been used for decades to monitor material quality based on particle size.

Wet sieve analysis can be utilized where the material analyzed is not affected by the liquid - except to disperse it.

Gradation affects many properties of an aggregate, including bulk density, physical stability and permeability.

With an open gradation, the bulk density is relatively low, due to the lack of fine particles, the physical stability is moderate, and the permeability is quite high.

These mechanical properties determine whether a given soil can support the proposed engineering structure.