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Soil classification (AASHTO and USCS)

AASHTO M 145 · ASTM D2487

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Soil classification (AASHTO and USCS)

AASHTO M 145 · ASTM D2487

Classifies the material finer than 75 mm (3 in.) from its sieve analysis and Atterberg limits.

Percent passing
Atterberg limits (minus No. 40 fraction)

Optional for a nonplastic soil that is mostly coarse.

Grain sizes (for coarse soils with little fines)

Needed only when 12 % or less passes the No. 200 sieve.

Example values: a sandy lean clay. Rules follow FHWA NHI-06-088, chapter 4.

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