1. FAA Airport Pavement R&D Section Update

2. Presentation Outline Introduction Current Pavement R&D Projects
Construction Cycle 8
Construction Cycle 9
Test Cycle 2
Field Instrumentation Project
FAARFIELD 2.0
Aircraft Classification Rating – Pavement Classification Rating (ACR/PCR)

3. Airport Pavement R&D Section
Research Conducted at the FAA William J. Hughes Technical Center, Atlantic City, NJ, USA.
Aviation Research Division
Sponsor: FAA Office of Airport Safety and Standards (AAS-100), Washington, DC.
Doug Johnson
Provide Support for Development of FAA Pavement Standards
Advisory Circulars
10 Full-Time FAA Personnel
GDIT Support Contractor
William J Hughes Technical Center
Aviation Research Division (1 of 6)
Airport Technology R & D Branch (1 of 5)
Airport Pavement Sub-Team (1 of 2)

4. Research Collaboration
Support Contractor: CSRA International
Interagency Agreement: U.S. Army ERDC
CRDA: Boeing Commercial Aircraft Group
International MOAs: DGAC (France)
FAA Center of Excellence: PEGASAS
Iowa State University
Purdue University
Georgia Tech
Texas A&M University
Florida Institute of Technology
The Ohio State University
University Cooperative Grants:
Arizona State University
Rowan University
Pennsylvania State University
University of California, Davis/Berkley
University of California, Davis/ University of Michigan, Ann Arbor
University of Illinois
University of Massachusetts Dartmouth
University of North Texas/ University of Minnesota
Rutgers University
University of North Texas

5. Airport Pavement R&D Section Facility Layout
Safety
Technology
NAPMRC
Future
Asphalt Pavement Lab
Office Space
Soil Processing
Materials Laboratory
NAPTF

6. National Airport Pavement Test Facility (NAPTF)
Facility Facts:
FAA / Boeing (CRDA) Partnership at $21M
Opened April 1999
Fully Enclosed Facility
Accelerated Traffic Testing
900 ft. x 65 ft. of Test Pavement Surface
Full-scale Pavement Structures and Landing Gear Loads
Test Vehicle Facts:
Fully Automated & Programmed Wander Patterns
Up to 5-dual wheel configuration
Roughly 1.3 Million lbs.
Up to 75,000 lbs. per wheel

7. National Airport Pavement Materials Research Center (NAPMRC)
Facility Facts:
Dedication Ceremony August 2015
Indoor and Outdoor Testing Capability
Accelerated Traffic Testing
Outdoor: 150ft. x 300ft. & Indoor: 72ft. x 300ft.
Accelerated resurfacing
Heavy Vehicle Simulator – (HVS-A) Facts:
Temperature Control Capability
Up to 150°F
Capacity 10, ,000 lbs.
Single & Dual-Wheel Configuration
Dual (B )
Fully Automated & Programmed Wander Patterns up to 6 ft.

8. FAA NextGen Pavement Materials Lab
2010: Laboratory Opened
2013: AASHTO Material Reference Laboratory (AMRL)
2013: Cement and Concrete Reference Laboratory (CCRL)
Full Test Capabilities: Asphalt, Concrete, Soils
Advanced Test Capabilities:
Asphalt Pavement Analyzer (APA)
Asphalt and Concrete beam fatigue
Semi-Circular Beam (SCM)
Disk-Shaped Compact Tension (DCT)
Benefits to the NAPTF:
Quality Control of Testing
Expedient Testing of Materials During Construction
Perform Advanced Materials Characterization On-site
Development of Performance Based Specification
Aircraft loading conditions vs majority of labs focus on Highway loading conditions
APA testing 254 psi vs 100 psi
New Test Quip machine for Semi Circular Beam (SCB) testing
New Bench top for fine grain soil modulus.
Asphalt beam fatigue aircraft loading conditions
DCT on overlay-cyclic loading
SMA,WMA, and RAP mix characterization testing

9. Future Asphalt Pavement Lab
Entrance
Conference Rm
Admin Area
Storage
Binder Lab
Advances Asphalt Testing
Sieve / Fabrication Area
HMA mix Lab

10. Airport Pavement R&D Four Major Pavement Focal Areas
Pavement Thickness Design
FAARFIELD 1.4
Concrete or Asphalt
Support Anticipated Aircraft Loads for Design Life (20 Year)
Avoid Premature Failure
Minimize Construction Cost
Aircraft / Airport Compatibility
Support ICAO Compatibility Criteria (ACN-PCN Method)
Improvements
New Alpha Factors
ICAO Tire Pressure Categories
Computer Program - COMFAA
Changes Adopted by US and Worldwide
Airport Pavement Management
FAA PAVEAIR Program
Free Web Based Management Software
Airports Manage Pavement Inventory
FAA to Monitor AIP Grants
Nondestructive Testing and Evaluation
Roughness
Smoothness
Advanced Pavement Materials
New Technologies
Reduce Construction Cost
Improve Durability
Environmental Benefit
Active R&D
Warm Mix Asphalt
Establish standards for Gyratory Mix Design
Characterizing Subgrade Soil
Deicing Agents

11. Construction Cycle 8 - Concrete
Primary Objectives
PCC-on-Rigid Overlay Test: Test PCC overlay on existing PCC with target SCI of between (Follow-on to CC4 overlay tests)
Evaluate Comparative Joint Performance:
Longitudinal Joint: doweled versus alternate sinusoidal key
Transverse Joint: doweled versus undoweled (dummy)
Improve FAARFIELD Failure Model: Test full-scale slab strength & fatigue strength for different concrete strength and foundation conditions
Secondary Objectives
Develop overload criteria for rigid pavements
Effect of k-value vs. CBR in characterizing rigid subgrade

12. Construction Cycle 8 Test Layout

13. Rigid Overlay Summary Underlay SCI: North 79 South 68
Gear configuration:
North 6-Wheel (3D); South 4-Wheel (2D)
Traffic test:
Started 10/10/17
55k lbs wheel load
50 days (01/17), passes
Overlay SCI:
North 11(trafficking stopped on 01/17/18)
South 8 (trafficking stopped on 01/11/18)

14. CC8 –Distress Overlay Map
48th day - 29,370 passes
Off Set Joint Reflective crack

15. Performance (SCI) curve
North: Triple Tandem (3D)
South: Dual Tandem (2D) 15

16. As-built Properties

17. Performance (SCI) curve17

18. Performance (SCI) curve
IPRF Report and 06-03 18

19. Performance (SCI) curve19

20. CC8 Joint Comparison Evaluate Comparative Joint Performance:
Compare performance of doweled (Type E) and sinusoidal keyed longitudinal construction joints.
Compare performance of doweled (Type C) and undoweled (Type D) transverse contraction joints.
The Joint Comparison Test (JCT) is Phase III of CC8, a multi-phase rigid pavement full- scale test started in 2018.
Traffic on JCT March-November 2018.
The JCT covers an area 90 feet long by 60 feet wide.
The 24 slabs are divided into four groups of 6 slabs, each 15 × 15 ft.
Each group of slabs represents a different combination of longitudinal and transverse joint types.

21. CC8 Joint Comparison Example at CDG Airport, Paris, France (Gomaco)
Sinusoidal keyed longitudinal joints have been used successfully in France and elsewhere in Europe.
For the FAA, they have the potential to provide an alternate method to doweled construction joints.
Example at CDG Airport, Paris, France (Gomaco)
Consultant conservatively design longitudinal and transverse dowels throughout all pavement area.
This is NOT required by FAA. Only the final three transverse joints are required,

22. CC8 Joint Comparison
Type E doweled joints are currently the only type of construction joints allowed by FAA Advisory Circular 150/5320-6F for airfield pavements with large aircraft operations.
Both type C (doweled) and type D (dummy) contraction joints may be used for transverse joints. FAA Advisory Circular 150/5320-6F requires dowels only for the last three transverse joints from a free edge; however, many engineers specify dowels at all transverse contraction joints.

23. CC8 Joint Comparison - Layout

24. CC8 Joint Comparison – Crack Map
Distress Mapping at End of Stage I-Traffic Test, D Gear at 65,000 lb. Wheel Load

25. CC8 Joint Comparison – Crack Map
Distress Mapping at End of Stage II-Traffic Test, 3D Gear at 70,000 lb. Wheel Load

26. CC8 Joint Comparison

27. CC8 Joint Comparison

28. CC8 Joint Comparison - Analysis
Doweled contraction joints exhibited consistently higher load transfer efficiency compared to the dummy (undoweled) joints.
LTE values for doweled transverse traffic joints did not change under traffic.
LTEδ values for dummy transverse joints were strongly correlated to the ambient temperature in the NAPTF facility.
LTEδ along the longitudinal joints decreased continuously with accumulated traffic. In general, average LTEδ remained higher on the north test item than on the south, but both sides deteriorated at similar rates.
Under the action of rolling wheel loads, the system of slab and dowel experiences a repeated rotating motion, which gradually causes dowel loosening and fatigue.
The continuous nature of the keyed load transfer may contribute to better long-term performance compared to the doweled joint.

29. CC8 Joint Comparison - Conclusions
Sinusoidal keyed joints may provide a good alternative to FAA standard doweled longitudinal construction joints at airports. For the longitudinal joints, S-keyed joints demonstrated performance at least equivalent to doweled joints during trafficking.
LTE along the longitudinal joints diminished with traffic, with the bulk of the deterioration occurring in the first 5000 passes. For both doweled and sinusoidal longitudinal joints, there was still significant load transfer capability after more than 40,000 passes had been applied.
As expected, for the transverse joints, the doweled joints show better overall performance than undoweled joints. The dowel maintained a high degree of load transfer efficiency throughout the test. Undoweled joints exhibited large changes in load transfer efficiency in response to temperature changes.

30. CC8 Strength Fatigue - Layout
Improve FAARFIELD Failure Model: Test full-scale slab strength & fatigue strength for different concrete strength and foundation conditions
Objectives: Isolate these phases and obtain data:
Cracking Strength of Slabs
Bottom-up Crack Propagation - Notched
Crack Initiation and Propagation – Unnotched
Strength vs. Thickness of various subgrade supports
The FAA rigid pavement design procedure uses a failure model in which SCI is the measure of performance. In this model, the SCI follows an approximately linear deterioration function of the logarithm of coverages (N), as shown in Figure 1. The number of coverages to the first observed thorough crack, i.e., at which SCI just begins to diminish from its initial level of 100, is defined as Point B. An SCI of 80 (Point C in Fig. 1) is the FAA definition of structural failure of a rigid pavement. However, the above relationship between SCI and coverages does not reflect the complex failure mechanism of concrete pavements. Specifically, there is a lack of an adequate model of fatigue damage accumulation in the major stage of rigid pavement life before the appearance of significant cracks (i.e., Point A in Fig. 1)

31. CC8 Strength Fatigue - Layout
Group 1: North, Unnotched 650 psi PCC, CBR 7-8
Group 2: South, Notched 650 psi PCC, CBR 7-8
Group 3: North, Unnotched 650 psi PCC, CBR 7-8
Group 4: South, Notched 650 psi PCC, CBR 7-8
Group 5: North, Unnotched 900 psi PCC, CBR 7-8
Group 6: South, Notched 900 psi PCC, CBR 7-8
Group 7: North, Unnotched 900 psi PCC, CBR 3-4
Group 8: South, Notched 650 psi PCC, CBR 3-4

32. CC8 Strength Fatigue - Layout
106Days of Traffic: 8/27/2018 – 10/03/2019 (Outer Lanes-49,930 total passes)

33. Construction Cycle 9 - Asphalt
Objectives
Verify/Refine/Modify fatigue model based on the ratio of dissipated energy change (RDEC)
Effect of P-209 Layer Thickness on Pavement Life
Effect of Geosynthetics use on Flexible Pavement Performance
Cement Treated Permeable Base Performance
Strain Criterion for Allowable Overload

34. Construction Cycle 09 Layout
Standard NAPTV
Gear Configuration
58,000 lbs/wheel
Standard NAPTV Wander Pattern

35. CC9 North Longitudinal Cross Section

36. CC9 South Longitudinal Cross Section

37. Design Failure Passes (FAARFIELD 1.4)
Test Item
Experiment
Gear Load
Failure Passes
LFS-1N
Fatigue Model
58,000 lb. 3D
5,870
LFS-1S
2,250
LFS-2N
38,860
LFS-2S
13,010
LFC-3N
Geosynthetic
> 1,230 (unknown)
LFC-3S
LFC-4N
CTPB
3,090
LFC-4S
Control
1,230
LFC-5N
Overload
36,000 lb. D
27,000
LFC-5S

38. Test Cycle 2 Objectives - NAPMRC
Primary Objectives
Study the effects of cracking and rutting performance.
Study the effect of RAP in WMA.
Evaluate the performance of Warm Mix Asphalt technologies under aircraft wheel load.
Performance specifications for P-401 mix designs
Test Parameters
Tire Pressure: 254-psi
Pavement Temperature: Hot and Cold
Test Speed: 2-mph
Wheel loads: 61,300-lbs

39. Test Cycle 2 Layout - NAPMRC
Design is Completed
Construction Completed
Material
P-401 HMA
WMA (3)
RAP (2)
Sasobit
Advera
Evotherm
Tire Pressure
210 & 254 psi
Failure Criteria Cracking & Rutting

40. Pavement Cross Sections- Outdoor
SANDY SUBGRADE
CBR 15
P-401 HMA/WMA SURFACE
9 inches (229 mm)
P-209 CRUSHED STONE BASE
8 inches (203 mm)
P-154 SUBBASE
12 inches (305 mm)

41. Pavement Cross Sections- Indoor
CBR 15
9 inches (229 mm)
8 inches (203 mm)
12 inches (305 mm)
3 inches (76 mm)
6 inches (153 mm)
WMA SURFACE
WMA/RAP
WMA/RAP SURFACE
P-209 CRUSHED STONE BASE
P-154 SUBBASE
SANDY SUBGRADE

42. Test Parameters – Traffic Tests
Pavement Temperature: 120°F (49°C) measured at a depth of 2-inch (50 mm) below pavement surface.
Test Speed: 3-mph (4.8 kmph)
Failure criteria: 1-inch (25 mm) surface rut
(1.45 MPa)
(1.75 MPa)
(27.8 metric ton)

43. Traffic Tests
Sasobit w/ 20% RAP
Sections Tested
Data being analyzed

44. Field Instrumentation & Testing Program
Airports Completed
Denver (DEN)
Atlanta (ATL)
Newark (EWR)
New York (JKF)
Boston (BOS)
Cape May (WWD)
Philadelphia
Current Discussions
UC Davis, CA
Seattle-Tacoma (SEA-TAC)
Phoenix (PHX)
San Francisco (SFO)
Need: Provides better understanding of long term pavement behavior in the field under varied climatic and operating conditions, and improved paving materials characterization will conserve airport development funds and reduce the downtime of runways from construction and maintenance activities.
Research Goals:
More durable, long-lived airport pavements, reduced lifecycle costs, better prediction of pavement service life, and accurate assessment of aircraft-pavement compatibility
Pavement performance data under different climatic conditions.

45. Current FAA Airport Instrumentation Projects
= Completed
= FAA Consideration
SEA-TAC: PCCP
JKF: PCCP
EWR: HMA Overlay
BOS: HMA Overlay
UCD Airport: FDR
SFO: HMA
PHL: HMA/PCCP
WWD: HMA/SMA/WMA
DEN: PCCP
PHX: PCCP
ATL: PCCP

46. Philadelphia International Airport (PLH)
Runway 27L Extension and Associated Taxiways
New Construction on Taxiway P2:
- 18” P-501
- 17” P-401

47. PHL Sensor Installation Layout
18” P-501 Sections
28 Strain Gauges
6 Pressure Cells
17” P-401 Sections
16 Strain Gauges
2 Pressure Cells
DAQ Unit

48. PHL Objectives
Determine the response of concrete slabs and asphalt concrete under multi-gear aircraft such as A-350, B-777, etc.
Compare the performance of concrete slabs and asphalt concrete under aircraft load.
Evaluate the load transfer efficiency of the joint
Measure the temperature profile in concrete pavement and asphalt pavement. Study the effect of temperature profile on pavement response.
Evaluate curling in concrete slabs.
Measure the stress on top of subgrade and base layer under aircraft load for different pavement structure.
Characterize the subgrade, base, cement concrete and asphalt concrete materials.

51. New! FAARFIELD 2.0 Beta Support for ACR-PCR.
Release with next update of AC 150/
Modernized graphical user interface (GUI).
Job and section entry.
Improved start-up screen.
Explorer-based navigation.
Improved flow between screens.
All .NET compatible.
Rational data file structure.
On-demand report generation.
No change to thickness design requirements at this time.

52. Legacy Fortran Libraries (Removed)
Fortran libraries in FAARFIELD 1.4 were modified from original 1995 programs.
Still distributed by FAA under a software sharing agreement with Lawrence Livermore National Laboratory, the original NIKE3D developer.
Very significant limitations for .NET programming.
Unmanaged code.
Not under the control of .NET memory management services.
May lead to memory conflicts or crashes at runtime.
Obsolete data storage and retrieval methods.
Few young programmers have knowledge of Fortran.

53. New FAARFIELD Calling Structure
REPLACED BY:
FAAMeshClassLib
Visual Basic.NET Class Library
REPLACED BY:
FAASR3D
Visual Basic.NET Class Library

54. GUI Modernization Major improvements: Easier job and section entry.
Explorer-based navigation.
Improved screen re-sizing and appearance.
Improved flow between screens.
Ability to store traffic mixes.
Rationalized data file structure.
On-demand report generation.
Remove program logic from GUI controls.
Etc.

55. FAARFIELD 2.0 GUI Screenshot

56. Features of Modernized GUI
Multi-display interface.
Highly configurable process flow.
Consolidated data entry to single screen.
Open, resize, move, dock/undock, close screens independently.
Makes use of right-click context menus.
Resizable screens.
Allows working with multiple jobs & sections.
Switch between jobs/sections/pavement types with 1 click.
Cut and paste between jobs.
Standard Windows file management.
Built-in Windows tools for saving/opening jobs.
Section and job names follow Windows standards.
Built-in standard pavement section library accessible from menu.

57. What’s Coming – Preview of the ACR-PCR System
Developed in cooperation with ICAO Aerodromes Pavement Expert Group (APEG).
Designated ACR-PCR (Aircraft Classification Rating – Pavement Classification Rating) System
Participants included the major aircraft manufacturers, ACI World, FAA and DGAC-France.
Same concepts as current ACN-PCN method, but:
Fully layered elastic-based.
Uses uniform standard subgrade categories for flexible and rigid.
NO alpha factor, layer equivalency factors, top-of-base k, etc.
FAA developed program ICAO-ACR.
Visual Basic class library computes rigid & flexible ACRs.
Replacement for legacy ICAO ACN computer programs.
Open source library – supports linking to any PCN program.

58. ACR-PCR Current Status
Proposed amendment to Annex 14 on ACR-PCR has gone through State review with no objections.
After formal adoption by the ICAO Air Navigation Committee (ANC), there will be a four-year transition period from ACN-PCN to ACR-PCR:
Effective date July 2020.
Full applicability November 2024.
During transition, both systems will remain available.
An updated ADM Part 3 with the new procedures will be posted in the near future.
Training on ACR-PCR is planned.

59. ACR Methodology – Principles
Similar to ACN, except:
All structures are layered elastic (rigid and flexible).
Retains 4 standard subgrade categories, but defined by modulus (E) not CBR or k.
Flexible ACR considers all wheels in the main landing gear.
Standard tire pressure increased to 1.5 MPa.
Standard coverages increased to 36,500 for flexible ACR.
DSWL expressed in 100’s (not 1000’s) of kg.
For most aircraft, ACR numerical values are approximately 10X higher than equivalent ACN.
Mathematically Derived Single Wheel Load (DSWL)
Evaluation Landing Gear - Load at Max. CG
Defined tire pressure = 1.5 MPa
Operating tire pressure t t
Vertical strain at top of subgrade computed by LEA
The ACR numerical value is defined as two times the DSWL (expressed in hundreds of kilograms)

60. ACR-PCR Subgrade Categories
Category A B C D
Strength
High
Medium
Low
Ultra-Low
E Value, MPa
200
120 80 50
Range, MPa
E ≥ 150
150 > E ≥ 100
100 > E ≥ 60
60 > E
Categories are defined by E, not CBR or k.
Same categories for rigid and flexible pavements.
All values defined at top of subgrade.

61. ICAO-ACR Screenshots Example – Airbus A350 Flexible ACR
Note: ACR values are generally one order of magnitude higher than corresponding ACN.

62. ICAO-ACR Screenshots Example – Airbus A350 Rigid ACR
Note: ACR values are generally one order of magnitude higher than corresponding ACN.

63. ICAO-ACR Availability
Program is maintained by the FAA and will be posted on FAA and ICAO websites.
Free of charge.
As a .NET dynamic-link library (DLL), it can be linked directly to other applications that:
Compute ACR (e.g., for aircraft gear design).
Use the standard ACR computation to evaluate PCR.
Procedures for linking to ICAO-ACR will be given in an appendix to the ADM update.

64. Flowchart of PCR Calculation
Directly uses FAARFIELD structure and traffic list.
Planned replacement for COMFAA 3.0 & support spreadsheets.
Method yields uniquely defined PCR.
No more considering multiple potential PCRs for different critical aircraft.
Implemented in FAARFIELD 2.0
Solves problem of computing PCR for mixed traffic (narrow bodies and LR aircraft) without unnecessary operating weight restrictions.
Seamlessly handles HMA overlays on flexible pavements.

65. Practical research to support the field & ADO offices is the goal
Future Research
Geosynthetics Reinforcement
“Green” technologies such as Warm Mix Asphalt (WMA)
Stone Matrix Asphalt (SMA)
Recycled Asphalt Pavement (RAP)
Full Depth Reclamation (FDR)
Polymer Modified Binders
Shear failure of HMA
Performance of HMA overlays on Flexible & Rigid Pavements
Nanotechnology for Improved Material Properties
Advanced Materials Research
Advanced Performance Based Laboratory Testing Methods
Practical research to support the field & ADO offices is the goal
Increased Pavement Life – Reduced Cost – Minimum Down Time

66. FAA Technical Center Airport Pavement R&D
Thank You - Questions
FAA Technical Center Airport Pavement R&D