ABSTRACT
Unified Soil Classification System
[ASTM D 2487-93] is used for virtually all geotechnical engineering work except highway and road construction, where the
AASHTO classification system
[AASHTO M 145-87] is used. Both systems use the results of
grain-size analysis
and determinations of
Atterberg limits
to determine a soil’s classification. Soil components may be described as
gravel, sand, silt,
or
clay.
