 For elongated and flat particles a sieve analysis will not yield reliable mass-based results, as the particle size reported will assume that the particles are spherical, where in fact an elongated particle might pass through the screen end-on, but would be prevented from doing so if it presented itself side-on.Gradation affects many properties of an aggregate, including bulk density, physical stability and permeability.With careful selection of the gradation, it is possible to achieve high bulk density, high physical stability, and low permeability.