AASHTO T 311-20 covers the determination of the particle size distribution of granular soil material. This method utilizes the 6.3-mm sieve size for separation purposes. However, the sample tester may use an alternative sieve size (i.e., 4.75 mm, 2.00 mm, etc.). In this case, the alternative sieve size used must replace the 6.3 mm size throughout this procedure.