Two proposed ASTM standards provide test methods for determining particle size. They include ASTM WK11776, Test Methods for Particle-Size Distribution (Gradation) of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis, and ASTM WK38106, Test Method for Particle-Size Analysis of Soils Combining the Sieve and Sedimentation Techniques. Gradation is used to classify soils for engineering and agricultural purposes, since particle size influences how fast or slow fluids move through ...This story is related to the following:Trade Associations