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2.2. SOIL COMPACTION (MOISTURE-DENSITY RELATIONSHIP)
Determine optimum water content of soil
Find maximum dry density
Check soil moisture sensitivity
Design Requirement:
Strength - Slope stability
Compressibility - Settlement control
Permeability - Dam core (build up low permeable zone)
2.2.1. LABORATORY SOIL COMPACTION
General Procedure
① Prepare specimen.
② Add water.
③ Compact in specified mold with specified compaction energy.
④ measured.
⑤ measured.
⑥ Repeat 1-5 for various .
Test Results: Moisture-Density (Unit Weight) Relationship
=
Standard and Modified Proctor
AASHTO T99 or ASTM D 698 : Standard Proctor Test
-most state highway agencies
AASHTO T180 or ASTM D 1557 : Modified Proctor Test
-airports
2.2.2. FIELD COMPACTION
Highway Off-Ramp Compaction
Roller Compactors
Smooth Wheeled Roller
Compacts effectively only to 200-300 mm; therefore, place the soil in
shallow layers (lifts)
Vibrating Plates
For compacting very small areas
Effective for granular soils
Sheepsfoot Roller
Provides kneading action; “walks out” after compaction
Very effective on clays
Similar to padded drum roller, tamping-foot roller
Impact Roller
Provides deeper (2-3 m) compaction
e.g., air field