1. Evaluation of Subbase using the Superpave Gyratory Compactor
Mike Panko
Kevin McGarvey
Casey Hurt
Cameron Corini
Gregg Stevenson
Dr. Beena Sukumaran
Dr. Yusuf Mehta
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

2. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Background
Continuous loading from airplane wheels create ruts in pavement
Bigger and heavier planes with complex gear configurations make rut prevention more difficult
FAA believes rutting is caused by densification of subbase
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

3. NAPTF – Rutting Behavior
North wheel track of CC3 flexible pavements at 19,500 passes
Picture courtesy of NAPTF
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

4. Interface profile measurements in the LFC2 posttraffic trench
Field Compaction
Interface profile measurements in the LFC2 posttraffic trench
Courtesy of Garg and Hayhoe
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

5. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Outline
Background and Objectives
Results from testing on P-154
DGA Field to lab Comparison
Conclusions
Future Work
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

6. Research Approach SGC Compare Compaction Curves Nuclear Density Gauge
Field Compaction
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

7. Variables Angle Pressure # of Gyrations
Gyratory Compactor
Variables
Angle
Pressure
# of Gyrations
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

8. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Shearing Action
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

9. Gyratory Compactor and Soil Parameters
Angle Used: 1.25°
Pressure Used: 600, 800, 1000 kPa
# of Gyrations: 400 Gyrations
Water Content Ranges:1-2%, 2-3%, 3-4%, 4-5%, 5-6%
Sample Size: 3000 grams
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

10. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010

11. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
P-154 Results
Determined OMC using Modified Proctor
Compared SuperPave Gyratory Compactor Results to Modified Proctor
Determined Compaction Energy using a Pressure Distribution Analyzer
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

12. Compaction Properties of P-154
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

13. Comparison of SGC and Construction Compaction
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

14. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
MDD Placement in P-154
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

15. P-154 Comparison of Field and SGC Compaction
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

16. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Compaction Energy
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

17. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Shear Work
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

18. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Vertical Work
wv = vertical work (in-lb)
P = Pressure (600 kPa ~ 87 psi)
A = Cross Sectional Area (28.27 in2)
∆h = change in height of sample (in)
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

19. Compaction Energy per Gyration
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

20. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
DGA
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

21. Compaction Properties of DGA
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

22. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
MDD Placement in DGA
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

23. DGA Comparison of Field and SGC Compaction
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

24. Comparison of Energy per Gyration
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

25. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
SGC vs. Proctor Tests
Energy input from Proctor tests come from impact hammer.
The SGC can achieve higher densities than the impact hammer alone.
The energy input from the SGC comes from the vertical load applied, and the shearing caused by the gyratory movement, resulting in a higher energy.
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

26. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Conclusions
The SGC looks promising in evaluating compaction characteristics of unbound material during construction.
The results from the SGC appear comparable to the deflection in the field for P-154 and DGA but needs further evaluation.
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

27. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Future Work
Continue SGC testing at different moisture contents.
Obtain better field data for P-154, DGA and P- 209 for comparison with SGC tests.
Compare SGC compaction energy to field compaction energy.
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

28. Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010
Acknowledgements
FAA Grant #05-G-016
Dr. Gordon Hayhoe, FAA
Several FAA personnel for materials and assistance with the database
SRA International personnel for data access and assistance with the database
Sukumaran et al FAA Tech Transfer Conference, April 21, 2010

29. Questions ?

31. Comparison of Water Content at Top and Bottom of Sample
Date
Test
Gyrations
Pressure
(kPa)
% Water
Added by
weight
Moisture
Content
% (Top)
Content %
(Bottom)
Avg.
(%)
Difference
2/1/2008 1
400
1000
6.0
5.462
5.941
5.70
8.40 2
5.446
5.969
5.71
9.16 3
5.173
6.011
5.59
14.97 4
5.507
5.905
6.97
2/26/2008
500
5.183
6.090
5.64
16.09
5.167
6.041
5.60
15.58
2/28/2008
5.0
3.989
4.241
4.11
6.11
4.177
4.388
4.28
4.93
2/29/2008
4.093
4.368
4.23
6.50
4.351
4.603
4.48
5.63
4.485
4.630
4.56
3.20