1. Compaction Process in the Field
Dr. Talat Bader

2. Field Compaction
Dr. Talat Bader

3. DUMPING
DOZING

4. SCARIFYING
PICKING UP STONES

5. WATERING

6. Quality Assurance water content
Water contents must be closely monitored during field compaction.
If the soil gets too wet, it will be impossible to compact.
If the soil is too dry, it will be difficult to compact.
Since it is  easier to add than remove water, it is best to maintain   water contents on the dry side of optimal during field compaction.
Water content can be measured instantaneously using nuclear density probes.

7. Determine the Water Content (in Field)
2.0
1.9
1.8
1.7
1.6 5 10 15 20 25
Water content w (%)
Dry density ( Mg / m ) 3
Optimum Moisture Content
100% C
Line of
optimums A
OMC
Holtz and Kovacs, 1981

8. Determine the Water Content (in Field)
2.0
1.9
1.8
1.7
1.6 5 10 15 20 25
Water content w (%)
Dry density ( Mg / m ) 3
Check Point Method
100% C
Line of
optimums A B
Increase compaction energy
90% R.C.
Control
(1) Relative compaction
(2) Water content (dry side or wet side)
Note: the engineering properties may be different between the compacted sample at the dry side and at the wet side.
Holtz and Kovacs, 1981

9. Check Point Method Destructive Methods (Cont.)
Holtz and Kovacs, 1981
Check Point Method Destructive Methods (Cont.)
Sometimes, the laboratory maximum density may not be known exactly. It is not uncommon, especially in highway construction, for a series of laboratory compaction tests to be conducted on “representative” samples of the borrow materials for the highway. If the soils at the site are highly variable, there will be no laboratory results to be compared with. It is time consuming and expensive to conduct a new compaction curve. The alternative is to implement a field check point, or 1 point Proctor test.
2.0
1.9
1.8
1.7
1.6 5 10 15 20 25
Water content w (%)
Dry density ( Mg / m ) 3
Check Point Method
100% C
Line of
optimums A B X
Field check point X (it should be on the dry side of optimum)

10. COMPACTING

11. COMPACTION ON
SLOPES

12. CORNERS
COMPACTION NEAR

13. FINAL
LAYER

14. Estimating Performance of Compacted Soils

15. Quality Assurance Sampling in the field
The fill is sampled at random
Monitoring the compaction process should look for systematic errors
Dry unit weights of the compacted soil are measured to make sure that they are exceed the minimum acceptable values
To assure that the entire fill is compacted above the minimal density requirements
The average density measured should be well above the minimum required
Statistical methods can be used for this purpose.
Sampling rates:
Large fills: about 1 sampling per ( m2)/lift.
Small fills (< 1000m2):  2 or 3 samples / lift
Fill with lateral dimensions of 100m by 100m, one would expect to take sample measurements per lift.

16. Definitions Relative Compaction R Relative Density Dr
Relative Compaction R should not be confused with relative density Dr because they are not the same
Relative Compaction R
Relative Density Dr
df = Field Unit Weight
do = Optimum Unit Weight

17. Relative Compaction (R or R.C.)
Relative compaction or percent compaction
Correlation between relative compaction (R.C.) and the relative density Dr
It is a statistical result based on 47 soil samples.
As Dr = 0, R.C. is 80
Typical required R.C. = 90% ~ 95%

18. Determine the Relative Compaction in the Field
Where and When
Select the test site.
It should be representative or typical of the compacted lift and borrow material.
Typical specifications call for a new field test for every 1000 to 3000 m2,
Or when the borrow material changes significantly.
It is also advisable to make the field test at least one or maybe two compacted lifts below the already compacted ground surface, especially when sheepsfoot rollers are used or in granular soils.
Method
Field control tests, measuring the dry density and water content in the field can either be destructive or nondestructive.
Holtz and Kovacs, 1981

19. Statistical Evaluation
A median density is subjected to assure overall behavior of fill
A limit of variation is permitted
usually 3-5% less than median.
No more than 4-5% of the total tests on project below the limit.
Specified Median
Limit
Actual Median of all tests
% Compaction 85 90 95
100
105
110
115 20 30 40 50 60
% Tests
Densities are
unneeded
Reject

20. Question Time Thank you
Dr. Talat Bader