Presented to: By: Date: Federal Aviation Administration National Airport Pavement Test Facility Update Airport Pavement Working Group Don Barbagallo April 24, 2012

2 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Acknowledgement This presentation overview represents the work of many individuals including: –FAA Pavement Group –SRA International –Gemini Technology –McQueen Associates

3 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Current Ongoing Projects at NAPTF Construction Cycle 5 (Flexible Pavement). Construction Cycle 6 (Rigid Pavement). High Tire Pressure Testing on HMA. Reflective Cracking of HMA Overlay Testing. Alkali-Silica Reactivity Slabs. Single Wheel Module Instrumentation. Engineered Material Arresting System (EMAS) Testing. Runway Friction Test. Upgrades to the Test Vehicle. Future Tests.

4 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Post Traffic Testing CC5 examines the effect of multiple gear configurations on low strength subgrade flexible pavement life.

5 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 CC5 TRENCH AREA

6 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 CC5 TRENCH SUBGRADE CHARACTERIZATION Nuclear Density LWD CBR Measurement Profiles

7 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Preliminary CC 5 Trench Findings CBR Summary

8 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 CC 6 Rigid Pavement CC6 tests to determine the effect of concrete flexural strength on rigid pavement life (AC 150/5320-6E) specification. North Asphalt Stabilized Base South Econocrete Base MRS 1 = 500 psi TFS Total Passes = 45K MRS 2 = 750 psi TFS Total Passes = K + MRS 3 = 1000 psi TFS Total Passes = 45K + 52K + 70K

9 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 CC6 Rigid Pavement Tests Dr. David Brill & Mr. Josh Davis will present update on CC6 testing.

10 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 HMA High Tire Pressure Tests Ran tests over the winter of 2010/11. Rutting failure in the PG mix. Will continue testing the PG mix at 17 ºF higher temperature than for the PG mix. –High temperature can only be achieved during the summer. –Delayed because of CC6 testing. –Plan to partially groove section of heated pavement vs unheated pavement.

11 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Reflective Cracking Test Rig Goal: Develop design guidance for asphalt overlay of concrete pavements based upon full scale testing. AC 150/ D purely empirical solution AC 150/5320 – 6E FAARFIELD does not address problem. Cracking of asphalt overlays is a complex problem. –Environmental temperature expansion/contraction. –Thermal induced warping –Load induced fatigue

12 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Reflective Cracking Test Rig

13 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Reflective Cracking Test Rig Environmental temperature change simulation. –Interface temperature 32F –Movement = Sinusoidal 0 to 15 mils –Total Cycle Time = 6 minutes –Total # of cycles completed to date ≈ 2600 Instrumentation includes: –Strain gages: concrete, asphalt, and surface –LVDT’s measuring concrete movement – Thermistors Crack length monitored with photos. Dr. Hao Lin of Gemini Technologies will present data.

14 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Alkali-Silica Reactivity Testing Indoor, outdoor, & control slabs. Periodic dosing with potassium acetate solution whenever slabs dry out; about every weeks. On–going testing of slabs continues with little visual evidence of ASR. Planned grooving of slabs to expose aggregate to potassium acetate.

15 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Single Wheel Module Instrumentation Bending, Shear, & Torque Strain Gages Wheel Encoder

16 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 EMAS Testing Work performed under a CRDA between the FAA and Zodiac Aerospace (formerly ESCO). Comparison testing of new block design. Additional tests planned for May 2012.

17 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Aircraft Tire Friction Braking Testing Measure forces and friction coefficient for snow covered surface. Single wheel module with locked wheel

18 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Aircraft Tire Friction Strain Gage Ave Horizontal Force Sliding Friction Coefficient : µ ≈  0.13 Ave Vertical Force

19 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Planned Facility Upgrades Replace fiber optic data communication line – SPUs to control room. Add wireless access point for east end of building. Charging station for electric vehicles. 200,000 lb in-ground scale to facilitate calibration of test vehicle wheel loads.

20 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Test Vehicle Projects* Study to upgrade vehicle traction drives to incorporate dynamic braking. Procure and install hydraulic oil heating system. On-going load control system upgrade - Delta controllers and digital servo valves. * Ryan Rutter to further discuss

21 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Future NAPTF Schedule Continue Traffic CC6. Finish testing on CC5 HMA sections that were suspended due to cold weather. Remove/reinistall HMA overlay on reflective cracking rig. Plan and construct CC7 on the low-strength subgrade. Proposed testing to look at overload on flexible pavements. CC7 to also look at perpetual HMA pavements.

22 Federal Aviation Administration Airport Pavement Working Group Apr 24, 2012 Future NAPTF Schedule (continued) Repave the HTP pavement with warm-mix asphalt in conjunction with CC7 HMA construction. CC8 concrete pavement test planning beginning.  Joint design – load transfer of dowels for thick slabs on moderate strength subgrades.  Joint design – sinusoidal keyways vs. dowels.  As-built slab strength vs. predicted slab strength.  Slab aspect ratios.