Soil Tests
Tests on soils for embankment, subgrade and base: classification, Atterberg limits, moisture–density (Proctor) relationships, and in-place density for compaction control.
Atterberg Limits
The liquid limit, plastic limit and plasticity index: what they mean for a fine-grained soil, how the cup and thread tests work, and the one-point method.
Field Density of Soils
Measuring in-place density and moisture of soils and base with the nuclear gauge and sand cone, then percent compaction and the oversize correction.
Moisture–Density Relationship (Proctor Test)
Standard and modified Proctor tests: how the moisture–density curve gives maximum dry density and optimum moisture, the zero air voids line, one-point checks.
Soil Classification
How the AASHTO and Unified systems sort soils into groups from gradation and Atterberg limits, and what the group says about a soil as subgrade.