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FLORIDA APT UPDATE

FLORIDA APT UPDATE. Topics. APT facility HVS enhancements Major research projects Recently completed APT research Current APT research Concrete test road Benefits. Topics. APT facility HVS enhancements Major research projects Recently completed research Current research

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FLORIDA APT UPDATE

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  1. FLORIDA APT UPDATE

  2. Topics • APT facility • HVS enhancements • Major research projects • Recently completed APT research • Current APT research • Concrete test road • Benefits

  3. Topics • APT facility • HVS enhancements • Major research projects • Recently completed research • Current research • Concrete test road

  4. Accelerated Pavement Testing • Initiated in 2000 • Housed at the State Materials Office in Gainesville • Test site consists of eight 12 ft. linear tracks • Originally 150 ft. long • Seven tracks extended additional 300 ft. in 2011 • Two additional tracks include water table control • Loading performed using a Heavy Vehicle Simulator (HVS)

  5. Test Track Aerial View Original tracks Test Pits Extension

  6. Heavy Vehicle Simulator • Heavy Vehicle Simulator, Mark IV • Wheel speed up to 8 mph • Loading: 7 to 45 kips • Dual or single tires • Wander from 0 to 30 inches • Goodyear Unisteel G149 RSA, 11R22.5 (Dual Tire) • Goodyear G286 A SS, 425/65R22.5 (Super Single) • Michelin X One XDA-HT Plus, 445/50R22.5 Michelin X One XDA-HT Plus, 455/55R22.5

  7. Accelerated Pavement Aging System (APAS) 10 ft by 24 ft • Developed in 2005 • Simulate aging • 12 -10ft long heaters • Maintain 90⁰C at 2 in. depth • Water system • 65 nozzles • 90⁰C to 30⁰C in 7 minutes

  8. Binder Absolute Viscosity (Test Pits)

  9. Nondestructive Characterization

  10. Instrumentation Surface strain gauge Embedded asphalt strain gauge Soil pressure gauge Concrete strain gauge LVDT – joint movement

  11. Topics • APT facility • HVS enhancements • Recently completed research • Current research • Concrete test road

  12. Heating System (2001) • Six 9 ft. long elements attached to HVS test beam • Independently controlled to provide six heating zones • Thermocouples monitor asphalt temperature to a depth of 2 in.

  13. Insulated Panels • 2 inch Styrofoam panels with aluminum sheeting • Redesigned in 2006 • Replaced aluminum panels • Scaled down panel size • No forklift needed

  14. Automated Rut Measurements (2001) • FDOT Laser Profiling System • Fully automated • Entire surface profile is obtained • One set of profiles is taken in less than 15 minutes • Highly accurate • Does not tie up personnel

  15. Laser Sensors Right Laser Left Laser Laser Profiling System • Two 16 kHz Lasers, mounted 762mm (30 in) apart • Wheel carriage travels at 4 kph during data collection • Carriage is ‘unloaded’ Dual Selcom SLS 5200-300-RO

  16. Rut Depth Analysis

  17. Condition-Based Monitoring (2003) • Monitor HVS health • Prevent failures • Minimize downtime

  18. Semi-Automated Crack Analysis (2010) • Document crack development • Semi-automated analysis

  19. Topics • APT facility • HVS enhancements • Major research projects • Recently completed research • Current research • Concrete test road

  20. Research Project Selection • Planning, development and execution of research projects performed on an annual basis • Projects selected with support from FDOT’s Central & District offices, FHWA, industry, & Florida universities • Sustainable pavements • Long life pavements • Real-time monitoring of pavements • Techniques to expedite construction/maintenance and project acceptance • Methods to predict pavement performance (models, lab tests, etc.) • Techniques to prolong pavement life (innovative maintenance techniques and materials)

  21. Major Research Projects • 2001 - Evaluation of Superpave mixtures with and without polymer modified binders • 2003 - Assessment of the appropriate APT loading condition • 2004 -Evaluation of early strength requirement of concrete for slab replacement • 2005 - Evaluation of coarse and fine graded Superpave mixtures • 2006 - Evaluation of a thin concrete overlay of an asphalt pavement

  22. Major Research Projects • 2007 - Development of methodologies to assess cracking potential of asphalt mixtures • 2008 - Evaluation of asphalt strain gauge repeatability • 2009 - Impact of wide-base tires on pavement damage • 2010 - Validation of a gradation based performance evaluation method, Dominant Aggregate Size Range (DASR) Porosity

  23. Topics • APT facility • HVS enhancements • Major research projects • Recently completed research • Current research • Concrete test road

  24. Effect of ARMI on Instability Rutting • Asphalt Rubber Membrane Interlayer (ARMI) • Florida’s primary reflection crack mitigation technique • Districts suspect ARMI may contribute to rutting

  25. Pavement Structure Experimental Sections Control Sections 4-inch SP-12.5 4-inch SP-12.5 3-inch SP-12.5 2-inch SP-12.5 0.75-inch ARMI 0.75-inch ARMI 0.75-inch ARMI 2-inch SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 10.5-inch limerock base 10.5-inch limerock base 10.5-inch limerock base 10.5-inch limerock base 10.5-inch limerock base 12-inch granular subbase 12-inch granular subbase 12-inch granular subbase 12-inch granular subbase 12-inch granular subbase

  26. Rut History Lane slices indicated rutting confined to layers above the ARMI. Ignition tests on cores showed that ARMI had not migrated into structural layer.

  27. Summary – ARMI Contribution to Instability Rutting • An ARMI as deep as 4 inches contributed to instability rutting • Pavements with an ARMI rutted 20 to 50 times faster than those without an ARMI • FEA and lane slices indicated critical stress states above ARMI and at the tire edge • Contracted research effort initiated to evaluate ARMI alternatives

  28. Rut Resistance of Heavy Polymer Asphalt Binders • Localized rutting failures still occur at some intersections and other facilities with low speed and concentrated truck traffic • Recent studies have indicated a PG 82-22 asphalt binder could improve rut resistance • Cost of adding polymer vs. PG 67-22 (Fall 2011): • PG 76-22 is approximately $250/liquid ton more • PG 82-22 is approximately $350/liquid ton more

  29. Experiment Design (Rutting) 2 inch HMA with PG 67 - 22, PG 76 - 22 or PG 82 - 22 • Rutting • Three test track sections: two 2 inch lifts w/ PG 67-22, PG 76-22 & PG 82-22 binders • Loading performed at 120⁰F (50⁰C) • Fatigue • Two test pit sections: two 1.5 inch lifts w/ PG 76-22 & PG 82-22 asphalt binders • Loading performed at ambient temperature 2 inch HMA with PG 67 - 22, PG 76 - 22 or PG 82 - 22 1 - inch existing SP - 12.5 10.5 - inch limerock base 12 - inch granular subbase 1.5 inch HMA with PG 76 - 22 or PG 82 - 22 1.5 inch HMA with PG 76 - 22 or PG 82 - 22 10.5 - inch limerock base 12 - inch granular subbase

  30. Rut History As the amount of polymer increases, rut accumulation decreases

  31. Shear Flow As the amount of polymer increases, resistance to shear flow increases

  32. Tensile Strain As the amount of polymer increases, tensile strain decreases Previous test with similar mixture Modified binders offer 20 times greater fatigue resistance than unmodified binder PG 82-22 binder offers 10 times greater fatigue resistance than PG 76-22 binder

  33. Summary & Conclusions • APT study showed that PG 82-22 binder increased rutting and fatigue resistance • To date, two projects have been constructed with PG 82-22 binder (planning a third) • All have a history of significant rutting

  34. Topics • APT facility • HVS enhancements • Major research projects • Recently completed research • Current research • Concrete test road

  35. Current APT Projects • Asphalt rubber (AR) binder • 4.75-mm mixture • Cooperative research projects • Tire study TPF-5(197) • Fiber Reinforced Polymer (FRP) bridge deck

  36. PG 76-22 Asphalt Rubber (AR) • Background: PG 76-22 binder required on final structural course of Traffic level D mixes and top two structural courses of Traffic Level E mixes • Objective: Extend use of ground tire rubber (GTR) to structural course and provide alternative to SBS polymer • Minimum 7% GTR (may contain SBS polymer)

  37. PG 76-22 AR Study Test Sections Blend of GTR and Polymer PG76-22 ARB PG76-22 ARB PG 76-22 PM (Control) ARB-5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1.5-inch SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 1-inch existing SP-12.5 10.5-inch limerock base 10.5-inch limerock base 10.5-inch limerock base 10.5-inch limerock base 12-inch granular subbase 12-inch granular subbase 12-inch granular subbase 12-inch granular subbase (two binder suppliers) (two binder suppliers)

  38. 4.75 mm Mixture • Objective: Study use of 4.75 mm mixture for preservation treatment on low-volume roadways and overbuild layer 4.75-mm w/ PG 67-22 4.75-mm w/ PG 76-22 4.75-mm mixture w/ PG 67-22 4.75-mm mixture w/ PG 76-22 1.5-inch SP-12.5 w/ PG 76-22 1.5-inch SP-12.5 w/ PG 76-22 1.5-inch SP-12.5 w/ PG 67-22 1.5-inch SP-12.5 w/ PG 67-22 10.5-inch limerock base 10.5-inch limerock base 12-inch granular subbase 12-inch granular subbase 4.75-mm thickness ranges from ½ to 1 inch

  39. Wide-Base Tire Study • TPF-5(197), The Impact of Wide-Base Tires on Pavement – A National Study • Objective: Quantify the impact of WBT on pavement damage utilizing advanced theoretical modeling and validate results using full-scale testing • Scope: • Tire Contact stress measurements (WBT & DTA) • APT of pavement sections • FEM modeling of pavement loading • Calculation of pavement damage

  40. Wide-Base Tire Study • University of Illinois, Principal Investigator • Contact stress measurements, CSIR • APT • FDOT • UC-Davis • Ohio University • Modeling effort • University of Illinois • Delft University of Technology

  41. FRP Bridge Deck • Objective: Investigate alternative to open grid steel decks • Must have a solid riding surface, weigh less than 25 lb/ft2, have a low profile (5 in depth), and low noise • Background: Florida has the largest inventory of movable bridges in the US, most of which use open grid steel decks • High noise & vibration levels, costly maintenance

  42. FRP Experimental Plan • 20 kip tire load with no wheel wander • Three strain gauges placed on the underside of each panel below the wheel path (edge & mid-panel) • Four 6 ft wide x 4 ft long x 5 inch thick panels joined by three different joint types • Joint 1 – Low stiffness butted epoxy joint • Joint 2 – High stiffness butted epoxy joint • Joint 3 – 45⁰ chevron epoxy joint

  43. FRP Bridge Deck 18 kips

  44. Preliminary Results • Applied more than 300,000 passes • Significant system deflection > 0.5 inches in center of deck • Surface cracks initiated after < 5000 passes • No catastrophic failures of joints or panels

  45. Topics • APT facility • Recently completed research • Current research • Concrete test road

  46. Why Build a Test Road? • Provide a real-word testing ground • New construction, rehabilitation, and maintenance techniques • New materials and design methods • Develop cost effective long-life concrete pavements specific for Florida environment • Will be the only full scale concrete pavement test facility in the Southeast

  47. Test Road Location • Northbound US 301 / SR 200 • Minimal side streets • Minimal impact • Large truck volume • 30% trucks • 1 million ESALs/year US-301, Clay County SMO

  48. US-301 (Looking South)

  49. What Will the Test Road Look Like? • 2.5 mainline miles, parallel to existing NB lanes • Individual test sections will be 225 ft long • Test sections will be used to evaluate various design and construction features • Live traffic will be diverted to the test road • Traffic will be classified & weighed • Construction planned for 2015/16

  50. Impact of APT Research • Revision of pavement design and construction methods and specifications • Implementation or discontinued use of researched materials and methods • Informed policy decision making • Furthering knowledge/education of pavement engineers

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