NETTCP Earthwork Inspection
Particle Distribution Test AASHTO T27 application
• Determines the category of soil being used (Gravel, sand, silt, clay)
• Determines whether material is well or poorly graded.
Hydrometer Test AASHTO T88
• Characterizes the distribution of particles well below the #200 sieve (75 micron to 1
micron).
• This will predict whether the material will drain freely or behave in a plastic
manner when saturated.
Soundness AASHTO T104
• Simulates freeze-thaw cycles to identify materials that will break down.
LA Abrasion AASHTO T96
• Determines toughness of coarse particles to resist degradation.
Liquid Limit / PI AASHTO T89 & T90
• Liquid limit: Max water before soil phases from solid to fluid.
• Plastic limit: Min water soil can contain while still being plastic and rollable.
Define "Soil Density"
, • Unit weight of soil (total weight in a specific volume), varies with moisture and
compaction.
Three components contributing to Soil Density:
1. The space occupied by particles
2. The space occupied by air
3. The space occupied by water
Goal of compaction
• Minimize air space and maximize particle contact
Water content handling when expressing density
• Density is expressed as if no water is present (dry density).
Compactive effort for coarse grained soils
• Requires effort to overcome particle friction; can be done dry unless fracturing
occurs.
Why too much water decreases density
• Water displaces solids, reducing density.
Define proofrolling
• Used to gauge subgrade acceptability prior to base installation; supplements or
substitutes for density testing.
Particle Distribution Test AASHTO T27 application
• Determines the category of soil being used (Gravel, sand, silt, clay)
• Determines whether material is well or poorly graded.
Hydrometer Test AASHTO T88
• Characterizes the distribution of particles well below the #200 sieve (75 micron to 1
micron).
• This will predict whether the material will drain freely or behave in a plastic
manner when saturated.
Soundness AASHTO T104
• Simulates freeze-thaw cycles to identify materials that will break down.
LA Abrasion AASHTO T96
• Determines toughness of coarse particles to resist degradation.
Liquid Limit / PI AASHTO T89 & T90
• Liquid limit: Max water before soil phases from solid to fluid.
• Plastic limit: Min water soil can contain while still being plastic and rollable.
Define "Soil Density"
, • Unit weight of soil (total weight in a specific volume), varies with moisture and
compaction.
Three components contributing to Soil Density:
1. The space occupied by particles
2. The space occupied by air
3. The space occupied by water
Goal of compaction
• Minimize air space and maximize particle contact
Water content handling when expressing density
• Density is expressed as if no water is present (dry density).
Compactive effort for coarse grained soils
• Requires effort to overcome particle friction; can be done dry unless fracturing
occurs.
Why too much water decreases density
• Water displaces solids, reducing density.
Define proofrolling
• Used to gauge subgrade acceptability prior to base installation; supplements or
substitutes for density testing.
