Particle Size Distribution

Particle Size Distribution

Particle size distribution – the basic classification of a soil for use in construction is based on the gradation of individual particles present in a material. To determine this, the individual particles need to be separated before being passed over a set of sieves (for particle sizes down to 0.063mm) or subject to alternative sedimentation testing for particle sizes between 0-063 and 0-002mm.  Aggregations of soil are broken down by an oven dried sample of soil being washed over a 0.063mm sieve, material retained on this sieve being retained and again oven dried before being passed over a nest of sieves in order to provide the percentage of soil present for each sieve size.    Sedimentation testing, carried out by the pipette method, is used to determine the distribution of very fine particles in a sample and usually combined with a washed analysis to provide full grading details of a sample.