1. Ahmedabad Institute of Technology
ENCI 579

2. NAMES Name Enrollment No. Limbachiya Setu 140023106004 Manani Milan
Patel Garvish
Vnakar Jigar
ENCI 579

3. Compaction In-situ soils used as:
Bases for the construction of highway pavements
embankments or leveling material for construction projects
Compacted to improve their density: M/V
improves the soil’s strength
lowers it’s permeability
reduces future settlement
ENCI 579

4. Compaction
Evaluation of density as a result of compactive efforts with rollers and other equipment
common quality control measurement on soils at construction sites
density of a compacted soil is measured and compared to a density goal previously determined in laboratory tests
ENCI 579

5. Compaction Maximum Dry Density
Maximum dry density must be established for each soil type
clay soil after compactive effort Kg/m3
granular soil with no compactive effort may be well above this
Dry density of a soil fn (water content)
ENCI 579

6. Compaction Maximum Dry Density
ENCI 579

7. Compaction Maximum Dry Density
Compaction Control
Determine the maximum dry density for a particular soil under a certain compactive effort and the water content at which this density is reached.
MD/V
ENCI 579

8. Compaction Maximum Dry Density
ENCI 579

9. Compaction Maximum Dry Density
Compaction Test
Moisture density test
Proctor test
soil is compacted into 10 cm diameter mold for material passes 4.75 mm sieve (15 cm mold for coarser material)
soil is placed in 3 layers
each layer compacted 25 blows with a 2.5 Kg hammer dropping 30 cm ( 56 blows)
ENCI 579

10. Compaction Maximum Dry Density
25 blow/56 blow compactive efforts are the same and represent the compactive efforts of 1930 construction rollers
Compaction Test
sample of soil is mixed with water
mass of compacted sample is measured
water content determined
sample of soil is mixed with more water
repeated until density decreases
ENCI 579

11. Compaction Maximum Dry Density
Modified Compaction Test
Modified Moisture Density Test
Modified Proctor Test
Increased loading on our pavements
Increased compactive effort of equipment
Revised test of higher compactive effort is now often used
4.5 Kg hammer, 45 cm drop, 5 layers
higher maximum dry density/lower w/c
ENCI 579

12. Compaction Maximum Dry Density
*Volume of standard mold is cm3
**Dry density = density/(1+w)
ENCI 579

13. Compaction Maximum Dry Density
Zero Air Voids (ZAV) Curve
“the maximum theoretical density of a soil at various water contents” with no air left in the soil water mixture
ZAV rD = rW
1/RD + W
ENCI 579

14. ENCI 579

15. Compaction Maximum Dry Density
Maximum Dry Density of a soil is used in quality control
Specification requires a certain % of maximum dry density at optimum water content found by the compaction test for that particular soil
Ensures density
Reduces the compactive effort
ENCI 579

16. Compaction Maximum Dry Density
ENCI 579

17. Compaction Maximum Dry Density
ENCI 579

18. Compaction Maximum Dry Density
Note:
If the soil was below optimum water content it may be necessary to add water by spraying
The most important factor required for successful compaction is having the correct water content
ENCI 579

19. Compaction Field Density Tests
Sampling Methods
sample of compacted material taken
dry mass of the soil taken is determined
volume originally occupied by the sample is measured
field dry density = dry mass/volume of sample
Two sampling methods
balloon densometer
sand cone apparatus
ENCI 579

20. Compaction Field Density Tests
Balloon densometer
Dry mass of the soil is determined
Volume of the sample hole is found by forcing a liquid filled balloon into the test hole
A rubber membrane allows the fluid to fill all the cavities of the hole
The volume of fluid required is measured
density calculated
water content determined
ENCI 579

21. Compaction Field Density Tests
Sand Cone Apparatus
Dry mass of the soil is determined
Volume of the test hole is obtained from the mass of loose sand required to fill the hole
Sand is a uniform medium sand with a constant loose density
Volume=mass of sand / loose density of sand
density is calculated
water content determined
ENCI 579

22. Compaction Maximum Dry Density
Example 3-4 Sand-Cone Apparatus: A sand cone holds g. The loose density of the sand is g/cm3
Field Test Results:
Total weight of the soil g
Dry weight of the soil g
Initial weight of the sand-cone apparatus g
final weight of the sand-cone apparatus g
ENCI 579

23. Compaction Maximum Dry Density
Calculations:
Mass of the sand used g g = g
Mass in test hole g-851.0g = g
Volume of test hole g = cm3
1.430 g/cm3
Field dry density g/316.7 cm3 = g/ cm3
Field water content = 16.7%
547.9
ENCI 579

24. Compaction Field Density Tests
Nuclear Moisture-Density Gauge
Results are available within minutes
Increases equipment efficiency
Know that your construction methods are correct
Gamma rays are emitted into the soil
absorbed by the soil according to it’s density
rays that pass through the soil are measured by a detector
density is then calculated
ENCI 579

25. Compaction Field Density Tests
Nuclear Moisture-Density Gauge
Neutron radiation emitted into the soil
neutrons loose energy when they collide with hydrogen atoms in the soil water
detector measures the amount of moderated neutrons
water content can be calculated
Direct transmission mode
Backscatter mode
ENCI 579

26. Compaction Field Density Tests
ENCI 579

27. Compaction Maximum Dry Density
Corrected Maximum Dry Density
compaction test is usually done on materials finer than 4.75 mm
sample contains coarse grained sized particles
gravel in a soil composed mainly of fine grains can be compacted to 90% of their theoretical maximum density
assuming gravel RD=2.65
ENCI 579

28. Compaction Maximum Dry Density
Example Laboratory maximum density of a soil is 1900 kg/m3. Specifications require 95% compaction. In the filed, dry density of the soil is found to be 1810kg/m3. A visual check of the soil in the field indicates that it contains about 20% gravel sizes. (Scales can be used for a more accurate determination of the percentage of gravel.) Check for compaction.
ENCI 579

29. Compaction Maximum Dry Density
Corrected maximum dry density is:
0.80 x 1900kg/m x (90% x 2.65 x 1000kg/m3 = 1520 kg/m kg/m3 = 1997kg/m3
Percent compaction is 1810/1997 = 90.6% and is not acceptable
ENCI 579

30. Compaction Operation and Quality Control
Highway components that require compaction:
Subgrade (15-30cm) in depth, provides the foundation for the pavement structure
Fill material used to bring the soil surface up to the subgrade level (15-30 cm compacted lifts)
Backfill material
Layers in granular material used in pavement
Asphalt layers at the surface
ENCI 579

31. Compaction Compaction Equipment
Consists of various types of rollers and tamping equipment
self propelled
compacting wheels equipped to vibrate
cycles/minute for most soils and granular materials
smooth steel drums
drums with pads or “feet”
rubber tires
ENCI 579

32. Compaction Compaction Equipment
Vibratory Smooth Drum Rollers
one steel drum and rubber tired drive wheels
two steel drums one of which is the driver
effective for gravel, sand, silt soils
granular base courses and asphalt mixtures
mass of the drum is between 2-15 tonnes
utilized in layers from meters in depth
usually require 3-5 passes to produce specified density
ENCI 579

33. Compaction Compaction Equipment
Vibratory Smooth Drum Rollers
ENCI 579

34. Compaction Compaction Equipment
Padded Wheel or “Sheep’s Foot” Rollers
pads on the rotating drum and may vibrate
effective in clay and silty clay soils
punching action breaks the clay’s bonds which resist rearrangement of the grain structure
pressure exerted by the pad kpa depending on the size of the roller
utilized in layers of cm in depth
usually require 3-5 passes to achieve density
ENCI 579

35. Compaction Compaction Equipment
Padded Wheel or “Sheep’s Foot” Rollers
ENCI 579

36. Compaction Compaction Equipment
Pneumatic Tire Rollers
2-12 rubber tires on each axle
individual tires wobble or weave or move lower than adjacent tires to improve the kneading action
effective in clay and granular soils and asphalt mixtures can be kneaded and compacted
effective depths for soils or base courses is up to 15 cm (larger units of tonnes 30 cm)
ENCI 579

37. Compaction Compaction Equipment
Pneumatic Tire Rollers
ENCI 579

38. Compaction Compaction Equipment
Smooth Drum Non-vibratory Rollers
used for finishing or sealing passes on soils and granular layers
final leveling passes on asphalt layers
Vibrating Plates or Tampers
used for trench backfills
around structures where larger equipment can’t operate
larger tamping equipment is usually attached to excavators or other equipment
ENCI 579

39. Compaction Quality Control
Determine which materials are to be sampled and tested
Frequency of the testing and type of tests to be performed on the material
Transportation authorities usually have specifications outlining these criteria
Moisture Density 1/ soil type (or 5000 m subgrade)
Field Compaction 4/500 m of each layer
Method Specification vs EPS Specifications
ENCI 579

40. Thank You
ENCI 579