1. Use of Hamburg Loaded Wheel Track in Specifications & Research December 9-10, 2014 – Kenneth Ray Hobson, P.E. Havener Center, Campus of Missouri S&T 57 th Annual Asphalt Conference

2. To the Point Test Parameters Various Equipment Suppliers Test Methods Agency Specifications Reducing Variability –National Research –Local Research

3. Hamburg Test Parameters Reciprocating Rolling-Wheel Device –8” Diameter x 1.85” [203 x 47 mm] –158 ± 1.0 lbs. [705 ± 4.5N] –52 ± 2 passes / minute Measures –Rut Depth (mm) –Number of Passes

4. PMW WheelTracker

5. Troxler PMW WheelTracker

6. SmartTracker

7. James COX & Sons

8. Cooper Technology

9. GCTS HWTT - 100

10. Test Methods AASHTO T 334 –OHD L-55 Tex-242F

11. OHD L-55 Water Temperature –122 ± 2°F [50 ± 1°C] Number of Passes –Equivalent Single Axle Loads (ESALs) 18,000 lbs. / axle –Binder Type Rut Depth Measurement Location(s)

12. OHD L-55 Maximum Rut Depth –½ in. [12.50 mm] Stripping Inflection Point (SIP)

13. Louisiana Specifications

14. Oklahoma Specifications

15. PMW Rut Locations

16. PMW Mid-Point Locations

17. PMW Rut Sensor Locations 56 71 11

18. SOM TS2c Task Force Additional Investigation Needed –Specimen Preparation –SIP Analysis

19. NCHRP 20-07/Task 361 Revise AASHTO T 324 http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=3741

20. Reducing Variability NCHRP 20-07 Rut Depth Calibration

22. Draft Finding – NCHRP 20-07

23. Reducing Variability – 10-87-2B http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP10-87_FinalReport-PrecisionEstimatesofT324.pdf

24. Reducing Variability – 10-87-2B Wheel & Measurement Locations Manufacturer Verification Confinement of Molds Middle and Ends Eliminate Cutting of Specimens Increase Specimen Length

25. Reducing Variability NCHRP 10-87-2B Confine Joint (Plaster of Paris) Retighten Tray Bolts (30 minutes) Change Mold Material Use Reference Samples Average All Rut Measurements

26. NCHRP 10-87-2B Table 4-28 PropertyRepeatability %COV Reproducibility %COV Rut (mm)14.226.0

27. Reducing Variability ODOT Round Robin – Exp. 3 7 Wheels – Report July 11, 2012

28. Reducing Variability ODOT Round Robin – Exp. 4-5 ExperimentRut (10k) %COVN Rut (10k) %COVR 443.225.8 577.931.5

29. Final Reducing Variability Prevent Segregation –Specimen Preparation Mechanical Test Aging %Air Voids Grouping Specimen Orientation (top vs. bottom)

30. Questions? khobson@odot.org (405) 522-4986 khobson@odot.org (405) 522-4986