1. PERMANENT DEFORMATION BEHAVIOR OF THE GRANULAR LAYERS TESTED AT THE FAA’s NATIONAL AIRPORT PAVEMENT TEST FACILITY NAVNEET GARG, Ph.D. Senior Research Engineer, Galaxy Scientific Corp., EHT, NJ 82 nd Annual Meeting of the Transportation Research Board Modeling of Granular Bases for Flexible Pavements Session-556 January 14, 2003, Washington DC

2. PRESENTATION OUTLINE  National Airport Pavement Test Facility  Unbound Granular Materials  Measurements  Traffic Tests  Results  Summary

6. NAPTF PAVEMENT CROSS-SECTIONS 5-inch P-401 Surface 5-inch P-401 Base 8.5-inch P-209 Subbase MFS Medium- Strength Subgrade 5-inch P-401 Surface 5-inch P-401 Base High-Strength Subgrade HFS 5-inch P-401 Surface 5-inch P-401 Base 30-inch P-209 Subbase Low-Strength Subgrade LFS 5-inch P-401 Surface 8-inch P-209 Base 36-inch P-154 Subbase LFC Medium-Strength Subgrade 5-inch P-401 Surface 8-inch P-209 Base 12-inch P-154 Subbase MFC High-Strength Subgrade 5-inch P-401 Surface 11-inch P-209 Base HFC Low-Strength Subgrade 11-inch P-501 Surface 6-inch P-306 Base 8-inch P-154 Subbase LRS Medium-Strength Subgrade 10-inch P-501 Surface 6-inch P-306 Base 8-inch P-154 Subbase MRS High-Strength Subgrade 9-inch P-501 Surface 6-inch P-306 Base 6-inch P-154 Subbase HRS

7. PRESENTATION OUTLINE

8. Maximum Dry Density: 141.1 pcf Optimum Moisture Content: 7.10 % P-209 CRUSHED STONE BASE

9. Maximum Dry Density: 128.5 pcf Optimum Moisture Content: 6.5 % P-154 SUBBASE

10. SHRP P-46 RESILIENT MODULUS TEST RESULTS

11. PRESENTATION OUTLINE

12. Low-Strength Subgrade End High-Strength Subgrade End 6-Wheel Traffic Path 4-Wheel Traffic Path Pavement Center Line NE-MDD SE-MDD NW-MDD CL-MDD SW-MDD

15. LEFT OFFSET RIGHT OFFSET PEAK-1PEAK-2 PEAK-3 TOTAL DEFORMATION RECOVERED DEFORMATION UNRECOVERED DEFORMATION MDD RESPONSE-TIME HISTORY

19. RUT DEPTH MEASUREMENTS

21. PRESENTATION OUTLINE

22. TRAFFIC TESTS  Vehicle Speed: 5-mph (8-kmph)  Failure Criteria: 1-inch (25-mm) upheaval outside the traffic path  Wheel Load: -45,000-lbs (20.4 metric tonnes) per wheel -After 20,000 passes @ 45,000-lbs, LFS & LFC further tested @ 65,000-lbs (29.5 metric tonnes)

24. PRESENTATION OUTLINE

26. LFS – LAYER PROFILES

28. LFC – LAYER PROFILES

32. MFC-W – LAYER PROFILES

34. RUT DEPTH MEASUREMENTS

37. MFS-W – LAYER PROFILES

40. MFS-E – LAYER PROFILES

42. PRESENTATION OUTLINE

43. SUMMARY  Of the 6 flexible pavement sections tested- LFS & LFC –Rutting/shoving in P-401 layer, rutting in P-209 & P-154 layer. rutting in P-209 & P-154 layer. MFS & MFC –Rutting in subgrade, P-209 & P-154 layer. HFS & HFC – No signs of failure, traffic tests suspended.

44. SUMMARY  The total accumulated permanent deformation in the pavement structure over a complete wander pattern (66 passes) is a small fraction of the total range of the unrecovered deformation occurring during the wander cycle.  Recovered and unrecovered displacements due to traffic loading increased significantly as the pavement was trafficked to failure. http://www.airporttech.tc.faa.gov