VDOT Soils and Aggregate Compaction Test
Questions and Answers (2026/2027) |
Updated Review | A+ Verified
• Size -✓✓Described by particle or grain diameter or average dimension.
• Shape -✓✓The shape of the grains larger than .06 inches is inditingusable to the
naked eye
• Surface Texture -✓✓Refers to the degree of fineness and uniformity of a soil.
• Surface Forces -✓✓fine grained platey soils, electrical forces on the surface of
the grains. important of how they react with water
• Consistancy -✓✓texture and firmness of soil
• Cohesion -✓✓The mutual attraction of particles due to molecular forces and the
present of moisture films
• Sensisitvity -✓✓a characteristic of clays that describes the lose of strngth after
disturbance
• moisture content -✓✓how much moisture is in the void spaces
• Why are dense grades used more for aggregate bases -✓✓bc the dense gradation
provides more strength by filling voids
• If the soils is 100 percent saturated and the voids are full of water and has a high
MC -✓✓large void spaces and is loosely compacted
• If the soils is 100 percent saturated and has low MC -✓✓small voids and is
compact
• in the field: the soil moisture is near the liquid limit -✓✓a lot of settlement is
likely
, • in the field: the soil moisture is near the plastic limit -✓✓not a lot of settlement
is likely
• Compaction Percent -✓✓(field dry density/ Max Theoretical Density)*100
• Does a silty sand or clayey soil require more moisture control -✓✓silty sand
• What are reasons for unexpected density changes -✓✓temp, lift thickness, less
than 95 percent compaction, more compactive effort, moisture control, change in
material
• Bridging vs geofabric -✓✓bridging is when you overfill a swampy area to be
able to move across, geofabric is placed between swamp and bridge to keep the
moisture out
• No slope shall be steeper than what? -✓✓2H:1V
• Erosion and silt controls are put in when -✓✓before any land disturbance
• What cut sections require grubbing and clearing -✓✓all
• How deepo are fill sectoins grubbed and cleared -✓✓less than 5 feet
• Grade to drain practices -✓✓crown surface, roll surface, direct water, install
slope drains, install side drains
• Embankment materials requirments -✓✓must not contain: muck, frozen
material, roots, sod, other deleterious material
meet AASHTO requirments
• Types of embankement fills -✓✓regular excavation, borrow excavation,
commercial sources, lspecialized materials that is approved by VDOT
• lift thickness -✓✓8" loose
6" compacted
• Moisture layer -✓✓+- 20% optimum moisture
Questions and Answers (2026/2027) |
Updated Review | A+ Verified
• Size -✓✓Described by particle or grain diameter or average dimension.
• Shape -✓✓The shape of the grains larger than .06 inches is inditingusable to the
naked eye
• Surface Texture -✓✓Refers to the degree of fineness and uniformity of a soil.
• Surface Forces -✓✓fine grained platey soils, electrical forces on the surface of
the grains. important of how they react with water
• Consistancy -✓✓texture and firmness of soil
• Cohesion -✓✓The mutual attraction of particles due to molecular forces and the
present of moisture films
• Sensisitvity -✓✓a characteristic of clays that describes the lose of strngth after
disturbance
• moisture content -✓✓how much moisture is in the void spaces
• Why are dense grades used more for aggregate bases -✓✓bc the dense gradation
provides more strength by filling voids
• If the soils is 100 percent saturated and the voids are full of water and has a high
MC -✓✓large void spaces and is loosely compacted
• If the soils is 100 percent saturated and has low MC -✓✓small voids and is
compact
• in the field: the soil moisture is near the liquid limit -✓✓a lot of settlement is
likely
, • in the field: the soil moisture is near the plastic limit -✓✓not a lot of settlement
is likely
• Compaction Percent -✓✓(field dry density/ Max Theoretical Density)*100
• Does a silty sand or clayey soil require more moisture control -✓✓silty sand
• What are reasons for unexpected density changes -✓✓temp, lift thickness, less
than 95 percent compaction, more compactive effort, moisture control, change in
material
• Bridging vs geofabric -✓✓bridging is when you overfill a swampy area to be
able to move across, geofabric is placed between swamp and bridge to keep the
moisture out
• No slope shall be steeper than what? -✓✓2H:1V
• Erosion and silt controls are put in when -✓✓before any land disturbance
• What cut sections require grubbing and clearing -✓✓all
• How deepo are fill sectoins grubbed and cleared -✓✓less than 5 feet
• Grade to drain practices -✓✓crown surface, roll surface, direct water, install
slope drains, install side drains
• Embankment materials requirments -✓✓must not contain: muck, frozen
material, roots, sod, other deleterious material
meet AASHTO requirments
• Types of embankement fills -✓✓regular excavation, borrow excavation,
commercial sources, lspecialized materials that is approved by VDOT
• lift thickness -✓✓8" loose
6" compacted
• Moisture layer -✓✓+- 20% optimum moisture
