2014 PAPA Asphalt Paving Conference

1. 2014 PAPA Asphalt Paving Conference 2012 Gmm Verification Pilot Projects and Round Robin Lab Study

2. History – How We Got Here • October 2006 FHWA Stewardship Review • July 17, 2007 Reported HMA Findings: • “The only State verification of the maximum theoretical density is performed at the mix verification of the mix design which is performed once a year. At the laboratories that were visited it was noted that the laboratories did not have the equipment for mechanically shaking the sample during the test as now required by AASHTO T-209” • July 17, 2007 Reported HMA Recommendations: • “The State should validate the maximum specific gravity (Gmm) value during production that is used for determining density. The AASHTO test procedure T-209 now require mechanical agitators and field labs visited did not have mechanical agitators on site.”

3. History – How We Got Here • March 31, 2008 – Bulletin 27, Change 3 • Revisions to Appendix I: • Clarify and delete certain equipment options • Clarify sample size • Clarify and revise mixture conditioning procedures in T 209 • April 4, 2008 – SOL# 421-08-01 • Implement Bulletin 27, Change 3, Appendix I Revisions immediately for all Producers. • April 23, 2008 – SOL# 421-08-03 • Apparatus & Procedures Checklist • Based on Bulletin 27, Change 3, Appendix I Revisions • Photos of Gmm Setup at PennDOT Lab

5. History – How We Got Here • June-August 2009 – Gmm IA Pilots • LTS test loose box samples collected at Plant • Retest exact sample as Producer (plastic bag samples) • July 2009 - AASHTO T 209-09 • Revised minimum sample sizes • Required Mechanical Agitation Device • January 2010 - PASIN LSOP Committee • Decision/supporting data to allow metal vacuum bowls • Decision/supporting data to allow mass in water method • July 2010 - AASHTO T 209-10 • Method A – Mechanical Agitation • Method B – Manual Agitation

6. History – How We Got Here • November 15, 2010 – Bulletin 27, Change 4 • T 209, Test Method A – Mechanical Agitation • Allowed vacuum bowls and mass in water • Referenced revised T 209 Min. Sample Sizes • Clarified conditioning for mix designs with absorptive CA • September/October 2010 – 2010 Gmm Verification Pilots – Plant Samples • 135 Plant Samples Collected and Tested by LTS • January-June 2011 – Consultant John A. D’Angelo • Gmm Data Analysis and Proposed Verification Procedure • Jun2012-Jan2013– Gmm Verification Pilot & RR Study

7. D’Angelo’s Proposed Verification Process • Systematic Approach – i.e., by JMF and can include multiple ECMS projects • Field Samples for both Producer QC and PennDOT Samples • IA Samples • Independent Verification (F&t tests) • Third-Party Dispute Resolution =Contr. Box =DOT Box =Dispute Box X or O = IA = Independent Assurance = Tested by Third Party if IA not ± 0.024 = Independent Field Verification O = Not Tested unless IA or F&tdoes not compare

8. 2012 Gmm Verification Pilot Projects

9. 2012 Gmm Study Plan & Round Robin

10. 2012 Gmm Data Analysis • 1130 Total Gmm Test Results • Missing Data • Plant QC Gmm – Filled missing dates using ESB data • Only 22 of 30 mix designs had LTS FV Samples • Only 11 of the 22 mix designs had more than 2 LTS FV Samples • Only 15 of 30 mix designs had Producer IF Samples • 9 of the 15 mix designs had more than 2 Producer IF Samples • Paired t-test • Causes for differences.

11. Missing Plant QC Data Filled from ESB

12. P-Value for Two-Tailed Paired t-Test Difference is statistically significant if P-value is <.05. "Red" indicates that there is a statistical difference in the specific gravity values for the two corresponding comparison groups. The darker the red color the more statistically significant the differences are. "Green" indicates the two groups of values are similar; with dark green indicating that the two groups of data are very similar.

13. P-Value for Two-Tailed Paired t-Test Difference is statistically significant if P-value is <.05. "Red" indicates that there is a statistical difference in the specific gravity values for the two corresponding comparison groups. The darker the red color the more statistically significant the differences are. "Green" indicates the two groups of values are similar; with dark green indicating that the two groups of data are very similar.

14. P-Value for Two-Tailed Paired t-Test by JMF Producer PV vs. LTS FV 10 of 30 Mix Designs with enough data 2 of 10 significant difference Producer IF vs. LTS FV 5 of 30 Mix Designs with enough data 3 of 5 significant difference

15. Differences – LTS IA vs. Producer IA (Field) +0.024 -0.024

16. Differences – LTS PV vs. Producer PV +0.024 -0.024

17. Differences – Hanson PV vs. Producer PV +0.024 -0.024

18. Differences – LTS IF vs. Producer IF +0.024 -0.024

19. Difference – Hanson IF vs. Producer IF +0.024 -0.024

20. Difference – Producer PV vs Producer IF +0.024 -0.024

21. Differences – LTS FV vs. Producer PV +0.024 -0.024

22. Differences – LTS FV vs. Producer IF +0.024 -0.024

23. Test Method Options & Procedures • Agitation • Mechanical = 20 of 21 (1 unknown) • Manual = 0 of 21 (1 unknown) • Variable Frequency= 11 of 21 (11=High) (1 unknown) • Container • Metal Bowl = 12 of 21 (1 unknown) • Metal Pycnometer = 8 of 21 (1 unknown) • Glass Pycnometer = 0 of 21 (1 unknown) • Mass Determination • Mass in Air = 5 of 21 (2 unknown) • Mass in Water = 14 of 21 (2 unknown)

24. Test Method Options & Procedures • Sample Size • 100% Met Min. = 10 of 21 (3 unknown) • <100% Met Min. = 8 of 21 (3 unknown) • Absorptive CA • Non-Absorptive = 20 of 26 (4 unknown) • Absorptive = 6 of 26 (4 unknown) • Conditioning Time • Non-Absorptive = Still being analyzed • Absorptive = Still being analyzed • Conditioning Temp • 58-28 = 5 of 5 (2=WMA, 3=RAP) • 64-22 = 5 of 17 (3=WMA, 2=RAP) • 76-22 =4 of 8 (all low)

25. Questions