A sieve is a further device for measuring durability. Although not all standard
procedures for sieving are suitable, those which comprise the use of balls between the
screens can be used. By vibrating a pellet sample in a sieve apparatus, abrasion and
perhaps fragmentation will occur through the action of (rubber) balls. Variables in this
device are the sieve openings, the number of balls, the amplitude, screening time and
eventually the use of interval sieving. Particle size distribution obtained by dry sieving
may add useful information when the influence of sieving (under standardised conditions)
for example is expressed in terms of the modulus of fines or the modulus of
uniformity before and after sieving