1. NCAT Pavement Test Track
2018 Track Alabama Test Sections

3. Content
2018 research cycle
Alabama sections
Practical takeaways

4. 2018 Track Research Focus Balanced (performance optimized) mix designs
Which tests work, construction, aging protocols
Smaller, finer mixes for cracking, durability
Higher RAP, richer mixes, “green” rejuvenators

5. Alabama Sponsorship Enhanced durability of OGFC surfaces (E9, E10)
Life extension from preservation (PG)
Asphalt mix performance testing (CG)
Dense graded 50 PSY (<1/2 inch) thinlay (N11)
SMA 4.75 NMAS 80 PSY (3/4 inch) thinlay (N10)

6. Alabama OGFC Sections (E9, E10)
APAI – 12/2/08 6

7. Full Depth Rapid Rebuild (S9)

8. Dense Graded Thinlay (N11)
Developed from W62003 (16 years, >51M ESALs)
ALDOT’s desire to implement MDOT finding
History of success with other thinlays variants
60 gyration Superpave mix design (LMS waiver)
6.1% AC67-22, 58% LMS, 22% Sand, 20% F-RAP
EAP’s experience with City of Opelika overlay.

9. Low Cost Opelika Overlay

10. Dense Graded 50 PSY Thinlay (N11)

11. Mat Texture

12. SMA Thinlay (N10) Developed from W32017 (2 years, 4.7M ESALs)
ALDOT’s desire to implement W3 finding (w/o Bauxite)
50 blow Marshall mix design (LMS waiver)
6.0% AC76-22, 62% LMS, 13% GRN, 5% Flyash, 20% F-RAP
Difficulty locating local materials for 4.75 NMAS mix.

13. Pelletized Cellulose Fibers

14. Surface Friction 80# SMA (59G,40B,1F) Epoxy Bauxite
50# DGA (58L,22S,20R)
80# SMA (62L,13G,20R,5F)
Overall Track Average

15. NCAT Three Wheel Polishing Device

16. Wheel Tracked Path

17. Dynamic Friction Tester

18. Quest for a Practical Cracking Test(s)

19. Marshall Press IDT (TSR)

20. Indirect Tension Testing (TSR)
Peak Load
Index = Energy / Rate
Crack Rate
Fracture
Energy

21. https://automeris.io/WebPlotDigitizer/

22. Construction Quality TestingBennert 2018
77°F
122°F

23. Takeaways www.pavetrack.com (asphaltresearch, 2018Track)
OGFC enhancement w/ smaller NMAS, admixtures
High performance thinlay preservation options
Bauxite blends for enhanced friction surfaces
Potential for laboratory friction assessments
Marshall press for performance optimized mixes.

24. We may need to do more research on how much friction is enough and what are the most economical ways to develop tire-pavement friction.
23-25, 2021

25. Dr. R. Buzz Powell, PE 277 Technology Parkway Auburn, AL 36830
Assistant Director
277 Technology Parkway
Auburn, AL
Phone: (334)
Cell: (334)
Web:
Twitter: 25