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Murphy Flynn Construction Manager FAA National Airport Pavement Test Facility PowerPoint Presentation
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Murphy Flynn Construction Manager FAA National Airport Pavement Test Facility

Murphy Flynn Construction Manager FAA National Airport Pavement Test Facility

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Murphy Flynn Construction Manager FAA National Airport Pavement Test Facility

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  1. 30th Annual Airport ConferenceHershey, Pennsylvania March 7, 2007 Murphy Flynn Construction Manager FAA National Airport Pavement Test Facility 1

  2. Curling Monitoring at NAPTF • First three concrete test items built in 1999 failed prematurely from corner cracks • Investigation into slab curling began in 2000 – determine cause of excessive slab curl indoors at NAPTF • Various projects over several years • PCC Mix design • Slab dimensions • Moisture and temperature 2

  3. Twin Slab Project • Two single slabs placed and instrumented in October 2005 • Indoor slab • Outdoor slab Sensors CSG’s 36 Vertical Displacement 18 Thermistors 18 Relative Humidity 6 Embedment 10 Total 88 3

  4. Typical slab center sensors 4

  5. Finished Indoor Slab 5

  6. Finished Outdoor Slab 6

  7. Results from Twin Slab Experiment • Instrumentation showed slabs corners separating from stabilized base • Indoor slab curled approximately 200 mils at peak • Outdoor slab curled approximately 90 mils at peak • Seasonal variations and daily variations observed in both slabs • Multi year monitoring continues 7

  8. Results from Twin Slab • Moisture gradient is the primary factor creating slab curl • Temperature gradient was a minor secondary effect • Developed system for wet curing indoor slabs of test items to prevent early age curling • Developed a system to periodically apply water to indoor concrete test items to control long term curling and reduce corner cracking • Effectively reduced curling to 20 mils or less 8

  9. Curling Monitoring Atlanta Hartsfield-Jackson International Airport 9

  10. Curling Monitoring at Atlanta Hartsfield-Jackson International Airport • Objectives: • to measure slab curling stresses and vertical slab/base separation in the field • compare slab behavior recorded at the NAPTF to behavior of actual airfield slabs • Eventually include slab curling effects in failure models 10

  11. Atlanta Taxiway E Instrumented Pavement Project • Three PCC slabs were instrumented during the reconstruction of RWY 8R-26L and parallel TWY E • Sensors were installed Oct. 16-18, 2006; Concrete was placed Oct. 18, 2006 • Instrumentation had to be more robust than those used at NAPTF 11

  12. Atlanta - Project Location RWY 8L – 26R RWY 8R – 26L ACCESS ROAD TWY E 12

  13. Atlanta Taxiway E –Instrumented Slabs Location 13

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  24. Atlanta Taxiway E Sensor Installation Sept./Oct. 2006 24

  25. Automated Data Acquisition System • Initial data acquired manually. Permanent data acquisition system will be installed late March. • System trialed at FAA Tech Center • Panasonic Tough Book laptop • Cellular modem IO Tech Data Acquisition System Mitsubishi Programmable Logic Controller 25

  26. Remote Power Supply • Power supply trial set up at FAA • Tech Center • 4 – 120 Watt solar panels • 400 Watt wind generator • Power to be mounted near data collection cabinet 26

  27. Concrete Research 27

  28. Innovative Pavement Research Foundation (IPRF) • FAA has partnered with industry to focus on Concrete research for airfields Program established 2001. • Cooperative Agreement with FAA. • P.I.: Gerald Voigt, ACPA • IPRF Program Manager: Jim Lafrenz • FAA Program Manager: David Brill • Research is funded 100% through FAA grants. • Projects are monitored by IPRF Technical Panels. Panel members include FAA and outside experts. • More information: http://www.iprf.org 28

  29. IPRF Projects 04-2 and 06-3:Concrete Overlay Parameters • NAPTF Construction Cycle 4 (CC4). • Project performed at NAPTF by Quality Engineering Solutions (QES) under contract to IPRF. • QES designed & constructed 3 test items on nominal 8 CBR subgrade (300 LF total). QES is responsible for monitoring the tests, does all analysis & prepares the final report. • Under terms of the Cooperative Agreement with IPRF, the FAA prepared the subgrade, performed plate load tests & operated test vehicle per QES plans.. • Final trafficking of CC4 test items took place on 10/3/06. • Plan for 2007-8 is for QES to perform Phase B testing on reconstructed overlays using IPRF FY06 funds. • Funds: • Phase A (04-2): $900K • Phase B (06-3): $900K 29

  30. CC4 Test Item Profiles WEST EAST 30

  31. IPRF Project 02-04:Airfield Pavement Smoothness Criteria • Comparative analysis of "off-the-shelf" pavement smoothness measurement equipment, technology and indices. • Define appropriate smoothness criteria to be used for acceptance, rehabilitation. • Limited to PCC pavements. • Contractor: APR Consultants, Inc. • Funds: $262K • Final report available 2007. 31

  32. IPRF Project 03-01:Design and Construction Guide for in Pavement Lighting • Best Practices document. • Addresses conflicting requirements between civil engineering and electrical engineering details. • Summary of practices that result in satisfactory installations resulting in minimal maintenance requirements. • Contractor: Burns Engineering • Funds: $106K • Final report available 2007 32

  33. IPRF Project 04-01:Develop a New Airfield Concrete Pavement Specification • IPRF will make recommendations to FAA for update to Item P-501, Portland Cement Concrete Pavement. • Address all areas of current spec, including concrete mix design; equipment; concrete placement; opening requirements, etc. • Emphasis on end product requirements. • Contractor: CTL Group • Funds: $411K • Final IPRF report & proposed specification: 2007 33

  34. Alkali-Silica Reactivity (ASR)Research Program • What is ASR? • A chemical reaction that occurs when silica in the aggregate and alkali in the cement react in the presence of water. • The reaction product is a gel that absorbs water and swells, causing cracking. • Potential distresses include cracked and misaligned slabs. There may also be an increased FOD hazard. • ASR is becoming increasingly recognized as a problem at airports. 34

  35. IPRF Project 04-6: Lithium Admixtures and Properties of Early Age Concrete • Project studied properties of plastic and early-age hardened production concrete treated with lithium nitrate (LiNO3) as an admixture. • Combined field testing with laboratory investigations. • Looked at concrete properties including: Air content and unit weight, workability, strength (compressive and flexural), shrinkage, maturity. • Conclusions: • No significant effects on early-age properties at the recommended dosage. • Some statistically significant effects (e.g., reduction in 28-day compressive strength) found at 2 – 4 times recommended dosage. • Based on results, keep 100% dosage as recommended maximum. 35

  36. IPRF Project 03-10:Topical Application of Lithium • 5-year field study, $630,000. • Contractor is Vector Corrosion Technologies. • 3 U.S. Airports studied: • Cheyenne, Wyoming • Phoenix, Arizona • Atlanta, Georgia • Investigating use of topical lithium treatment to mitigate/retard ASR damage. Test Area at Cheyenne Regional Airport (TWY B) Lithium Application at Cheyenne Airport 36

  37. IPRF Projects 03-9 and 04-8:ASR and De-Icing Chemicals • Alkali-bearing chemicals are commonly used as anti-icing and ice melting agents at airports: • Potassium acetate (KAc) and sodium acetate (NaAc) • Sodium formate (Used in Europe but not common on the U.S.) • U.S. airports observed that deicers seemed to contribute to a rapid increase in ASR activity. • FAA sponsored an IPRF project to • determine the severity of this phenomenon. • evaluate procedures for mitigation. • Interim test procedure • Modified ASTM 1260 (mortar bar) test. 37

  38. Guidance on Mitigating ASR • FAA Guidance(http://www.faa.gov/airports_airtraffic/airports/construction/): • Advisory Circular 150/5380-8, Handbook for Identification of Alkali-Silica Reactivity in Airfield Pavements • Engineering Brief No. 70, Accelerated Alkali-Silica Reactivity in Portland cement concrete pavements exposed to runway deicing chemicals. Interim recommendations from IPRF deicer study. • IPRF Reports (www.iprf.org): • Test Method to Assess Potential Reactivity of Aggregates in Presence of Airfield Deicing Chemicals (Mortar Bar Test) • Lithium Admixtures (LiNO3) And Properties of Early Age Concrete. 38

  39. Hot Mix Asphalt Research 39

  40. Bridging the Gap • FAA study underway to bring Superpave methodology into large commercial airport HMA • Goal: Develop a specification that will produce equivalent or better HMA than current P-401 Marshall mixes • Marshall mixes have been performing well • Currently use PG binders • FAA P-401 gradations match closely to Superpave requirements 40

  41. Current FAA HMA Specifications • ENGINEERING BRIEF NO. 59A “ITEM P‑401 PLANT MIX BITUMINOUS PAVEMENTS (SUPERPAVE)” • Purpose : provide guidance on using asphaltic concrete mixtures designed with Superpave (gyratory) techniques. • Available online at: http://www.faa.gov/airports_airtraffic/airports/ construction/engineering_briefs/ 41

  42. Engineering Brief 59A • Currently allows the use of Superpave mixes on airports with gross aircraft weights of 100,000 lbs. or less • Requires mix to be developed using 100 gyrations for Ndes • Use PG binder recommended by local Department of Transportation 42

  43. FAA Study Phase I • Phase I: Study will produce a matrix of mixes using both Marshall mix design and Superpave mix design • Matrix will encompass: • Various aggregate geologies • Limestone • Basalt • Granite • Etc. 43

  44. FAA Study Phase I • Matrix will encompass: • Various asphalt binders • PG 64-22 • PG 70-22 • PG 76-22 (Polymer Modified Binders) 44

  45. FAA Study Phase I • Compare volumetrics of mixes • Measure volumetrics at 75 blow Marshall hammer (current FAA spec.) • Measure volumetrics at various compaction levels using Superpave gyratory compactor • Ndes gyrations 65, 75 and 100 • Identify appropriate Ndes level to match volumetrics of P-401 Marshall mixes 45

  46. FAA Study Phase I • Collect history and performance of existing projects • Identify airfields paved using EB 59 standards • EB 59 requires projects using Superpave to collect Marshall Stability and air voids of the Job Mix Formula. • Evaluate performance of pavement compared to design life. 46

  47. FAA Study Phase II • Performance Testing • Produce a select number Marshall mixes and Surperpave mixes • Superpave mixes will be produced at Ndes developed in Phase I volumetric testing • Proposed Performance tests • Repeated Shear at Constant Height using Superpave Shear Tester • (AASHTO T320 Method C) 47

  48. FAA Study Phase II • Proposed Performance tests • Rutting Susceptibility Using the Asphalt Pavement Analyzer • (AASHTO TP63) • Simple Performance Test, Repeated Load Testing in Uniaxial Compression • (NCHRP Report 465, appendix B) • Dynamic Modulus Test (E*) • (AASHTO TP62) 48

  49. AAPTP • The AAPTP was established in 2004 through a cooperative agreement between the Federal Aviation Administration and Auburn University • Funded through FAA grants • Projects are monitored by AAPTP Technical Panels. Panel members include FAA and outside experts. • More at http://www.aaptp.us/ 49

  50. AAPTP Superpave Projects • Project 04-03, Implementation of Superpave Mix Design for Airfield Pavements - $470,000: • Goal is to produce fully documented guidance on the procedures and processes needed to incorporate Superpave technologies into FAA standard airfield mix design practice. 50