This document discusses warm mix asphalt (WMA), which can be produced at lower temperatures than traditional hot mix asphalt (HMA). WMA uses additives to reduce production temperatures by 20-100°F. Benefits include potential fuel savings of 10-20%, extended paving seasons, reduced emissions, and improved working conditions. The Nebraska Department of Roads has conducted research on WMA, finding potential 15% fuel savings and no issues with performance compared to HMA. Based on successful research, Nebraska adopted a WMA specification in 2012 and plans to use it on several state and county road projects.

1. Impact of Warm Mix Asphalt
in Nebraska
Matt Beran, P.E.
Assistant Flexible Pavements Engineer
Nebraska Department of Roads

2. Overview

3. What is Warm Mix Asphalt?
(WMA)
• Hot Mix Asphalt designs that are modified to be produced, placed and
compacted at 20-100°F less than typical Hot Mix Asphalt (HMA).

4. What is Warm Mix Asphalt?

5. Types of Additives

6. Warm Mix Asphalt Benefits
• Fuel Savings

7. Fuel Savings
• Fuel prices almost 3 times higher than last year
• 10-20% potential fuel savings
• Potential savings of $1 million each year

8. Warm Mix Asphalt Benefits
• Fuel Savings
• Improved Workability
– Allows for longer haul distances
– Extended paving season

9. Longer Haul Distances

10. Extended Paving Season
• December Paving (1 hour haul)

11. Warm Mix Asphalt Benefits
• Fuel Savings
• Improved Workability
– Allows for longer haul distances
– Extended paving season
• Reduced Emissions (Greenhouse Gases)
– Will be key with continuing environmental
regulations

12. Reduced Emissions

13. Reduced Emissions

14. Reduced Emissions

15. Warm Mix Asphalt Benefits
• Fuel Savings
• Improved Workability
– Allows for longer haul distances
– Extended paving season
• Reduced Emissions (Greenhouse Gases)
– Will be key with continuing environmental
regulations
• Improved Work Environment

16. Improved Work Environment

17. Warm Mix Asphalt Benefits
• Fuel Savings
• Improved Workability
– Allows for longer haul distances
– Extended paving season
• Reduced Emissions (Greenhouse Gases)
– Will be key with continuing environmental
regulations
• Improved Work Environment
• Possible Less Aging of Asphalt Binder
• Improved Plant Performance
– Reduced wear on plant

18. Warm Mix Asphalt History
• 1997: First pavements constructed in Europe
• 2004: First U.S. field trails in Florida and North
Carolina
• 2006: Numerous field trails around U.S.
• 2007: First field trail in Nebraska
• 2008: Second field trial in Nebraska
– Over 200 WMA test sections across U.S.

19. Overview

20. Research Need
• Verify national findings
• Testing WMA with local conditions
– Both laboratory and field testing
– Evaluate if there is a superior type
• See if WMA can perform as good or better than
HMA

21. UNL Research Project Plan

22. Warm Mix Project Locations
• STILL NEED TO GET CORRECT GRAPHIC

23. Warm Mix Project Locations

24. Highway 12: Monowi to
Verdel
• Sasobit able to give 80°drop in temperature
• No problems when switching to Sasobit
• No blue smoke with Sasobit
• 15% fuel savings

25. Highway 14: Elgin to US-20
• 50°drop in temperature
• More viscous feeling than HMA
• No smoke with both Zeolite and Evothern
• Minimal fuel savings

27. Visual Evaluation (‘09 & ‘11)

28. Research Needs
• Verify National Findings
• Testing WMA with local conditions
– Both laboratory and field testing
– Evaluate if there is a superior type
• See if WMA can perform as good or better than
HMA

29. Overview

30. Benefits for Nebraska
• Accelerated timeline for implementation
• Increased NDOR confidence in WMA
• Increased contractor’s awareness
• Met FHWA goals for WMA
• WMA specification adopted January 2012
• Will be utilizing on at least 4-6 projects this year
– Also on 2-3 Country Projects

31. Warm Mix Asphalt Benefits

32. CREDITS
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