1. Kenneth Ray Hobson, P.E. – Bituminous Engineer khobson@odot.org
Superpave Today
City of Tulsa
May 13, 2011
Kenneth Ray Hobson, P.E. – Bituminous Engineer

2. Overview Asphalt Mix Design Methods Laboratory Mixture Compactors
Asphalt Binders
Aggregate Tests
Mix Design Proof Testing
Design by Traffic Volume

3. Overview Mix Design Notes Future Items of Note 2009 Std. Spec. 411
Links Of Note

5. Automatic Marshall Hammers

6. Texas Gyratory Hveem Compactor

7. Superpave Gyratory Compactor (SGC)

8. Limitations of Traditional Binder Specifications
Penetration & ductility tests are purely empirical
Tests are conducted at one standard temp (i.e ºF), despite different climatic conditions
Entire range of pavement temperatures (esp. low temp’s) not considered

9. Limitations of Traditional Binder Specifications
Asphalt cements can have different temperature and performance characteristics within same grade (Pen or Vis)
Not applicable to modified binders (more use in recent years)
E.g. Grades AC-20, PMAC-1C

10. Superpave Asphalt Binder Specification
The grading system is based on Climate PG
Min. pavement temperature
Performance Grade
Average 7-day max. pavement temperature

11. Performance Graded Binder Specifications
Based on Mechanical Properties
(DSR, BBR)
Modulus
Deflection
Load Response (Rate)
Other Tests Remain Unchanged
Mass Change, Flash Point, Elastic Recovery, etc. ER is known as PG+ Spec.
ODOT 2009 Std. Spec Table 708:2

12. Aggregate Tests Superpave similar to Hveem with added tests:
Fine Aggregate Angularity (FAA)
Bulk Specific Gravity (used for FAA and VMA computations)
Micro-Deval (30+ MESALs)

13. Mix Design Proof Testing
Marshall Cohesiometer
Hveem Stabilometer
Hamburg Rut Test

14. Design by Traffic Volume
Hveem – ADT
Lab Specimens (4” diameter) Compacted the Same (275oF)
Air Void Limits Adjusted by Traffic
Superpave –ESALs in 20 Years
Lab Specimens (6” diameter) Compacted More with More Traffic (300oF)
Air Void Limits Kept Constant

15. Mix Design Notes Ndes – Number of SGC Gyrations at JMF Binder
Nini – Number of SGC Gyrations backcalculated from Ndes Specimens
Density Similar to That Behind Paver
Nmax – Number of SGC Gyrations at End of Pavement Life (mix design only)

16. Future Items of Note WMA – The Future is here now!
Provides Many Benefits
Tack Coats – 0.15 gal/SY Diluted 1:1
Trackless Tack Emulsion – Near 100% Bonding
Pave Sprayer Applied PMCRS-1S – Near 100% Bonding

17. 2009 Std. Spec. 411
Table 411:2 – Calculate Density (RD) Based on Latest Gse at JMF Binder Content for Pay Factor
Table 411:4 – Binder Content (Pb) and Air Voids (AV) for Pay Factors
CPF = (4 x RD + (3 x AV) + (3 x Pb)) / 10

18. Future Items of Note Increased Binder Content by Special Provision
Possible Reduction in SGC Gyrations
Possible VMA Increase by 0.5%

19. Links of Note Construction Engineering Materials Division Contacts
Standards, Specifications, Materials and Testing
Materials Division Contacts
Materials & Testing e-Guide

20. Links of Note Guidelines (Binder Selection and Thickness by Type)
Approved Performance Graded Binders and Others
Approved Superpave Mix Designs
100 Years of Transportation 1911 – 2011

21. Links of Note
Approved List of Anti-Strip Additives and WMA Technologies
WMA Special Provisions
WMA – Information in Detail

22. Summary Asphalt Mix Design Methods Laboratory Mixture Compactors
Superpave Most Common in History
Laboratory Mixture Compactors
New SGC Compacts 6” Diameter Specimens
Asphalt Binders
Performance Graded Using Mechanical Properties
Aggregate Tests
Little Added
Mix Design Proof Testing
Rut Testing Prevents Premature Failure

23. Summary Design by Traffic Volume Mix Design Notes Future Items of Note
Based on ESALs for 20 Years
Mix Design Notes
SGC Gyrations Critical for Predictive Performance
Future Items of Note
WMA – Adopted Nationwide Faster than Superpave

24. Summary 2009 Std. Spec. 411 Links Of Note
Pay Factors – Increased for Density by 10% and Removed Gradation
Links Of Note
Sources for Additional Information
Updated Daily as Applicable

25. Special Thanks
Danny Gierhart, P.E. – Former Bituminous Engineer and Current Regional Asphalt Institute Engineer
Reynolds H. Toney, P.E., Materials Division Engineer
Audience
Especially Those with Questions

26. Questions?