The present test method covers the determination of the particle
size distribution of fine and coarse aggregates by screening.
Some aggregate specific cations that reference this method contain
grading requirements that include both coarse and stone aggregate
fractions. Instructions for the granulometric determination of said
aggregates are included.
The division of soil into different fractions, selected by the size of its
component particles, is called gradation distribution of a soil; The
particles of each fraction are characterized because their size is
between a maximum value and a minimum value, correlatively for
the different fractions in such a way that the maximum of a fraction
is the minimum of the one that follows it correlatively.
In coarse soils (gravel, sand, and non-plastic silt), with a simple
structure, the most important characteristic to deï??ne its resistance is
compactness; The angle of the grains and the orientation of the
particles also play an important, although minor, role.
One of the reasons that have contributed to the spread of gradation
techniques is that, in a certain sense, the gradation distribution
provides a classiï??cation criteria. The well-known terms clay, silt, sand, and
gravel have this origin and a soil was classified as clay or sand depending on whether it had this or that maximum size. The need for a soil classification system is not debatable, but the engineer must look for one in which the classification criteria are useful.
