Questions Solved Correctly.
unit weight, strength, stability of slopes, amount of settlement in structures - Answer loose
soils must be compacted to: increase (3), decrease (1)
compaction - Answer the densification of soil by removal of air and water by means of
mechanical energy
dry unit weight - Answer degree of compaction measures in terms of:
water - Answer compaction and rearrangement of particles facilitated by means of:
softening movement - Answer water acts as a ___ agent, and allows for the ___ of the soil
particles
3 25 - Answer in the standard proctor test, soil is mixed with varying amount of water and is
compacted to fill ___ equal layers by a hammer that delivers ___ blows to each layer
moisture content, soil type (grain-size distribution, amount and type of clay, specific gravity of
soil), compaction effort - Answer compaction is affected by: (3)
max dry unit weight optimum moisture content - Answer as the compaction effort is
increased: ___ increases, and ___ decreases
heavy rollers - Answer the modified proctor test uses ___ to represent better field conditions
5 heavier higher - Answer in the modified proctor test, soil is mixed with varying amounts of
water and is compacted to fill ___ equal layers by a ___ hammer at a ___ elevation
before - Answer water content needs to be adjusted ___ compaction
type of soil, size of project, compaction requirements, required production rate - Answer
choice of equipment for field compaction depends on: (4)
grid, sheepsfoot, smooth-wheel, (pneumatic) rubber-tired, vibratory - Answer most common
types of compactors (5):
, pressure (high contact), impact (dropping a weight), vibration, manipulation - Answer
compactions mechanisms (4):
shearing - Answer manipulation of soil impacts ___ forces
grid and vibratory - Answer two rollers suitable for granular (gravel and sand) soils
sheepsfoot - Answer ___ roller compacts soil bottom up
clay and silt - Answer sheepsfoot roller suitable for ___ soils
sheepsfoot - Answer roller with largest contact pressure (300-700psi)
rubber-tired - Answer ___ roller suitable for sandy and clayey soil
smooth-wheel - Answer roller with very low contact pressure (45-55psi)
vibration - Answer smooth-wheel roller not very effective without ___
vibratory - Answer ___ roller can be incorporated in any type of roller
off-center - Answer vibration in vibratory rollers produced by rotating ___ weights
thickness of the lift, contact pressure, number of passes - Answer factors affecting the
success of field compaction (3):
field unit weight - Answer evaluation of ___ is needed to ensure success of compaction
sand cone, nuclear, rubber balloon - Answer 3 methods used to determine field unit weight
inexpensive and durable slow - Answer the sand cone method of determining field unit
weight is ___ and ___ but ___
gamma - Answer the nuclear method of determining field unit weight uses ___ rays emitted
from the source and absorbed by the soil and water atoms