1. Warm-Mix Asphalt: A Window to a Better Road Phase 1
Hosin “David” Lee, P.E. Ph.D., Professor
Public Policy Center,
Department of Civil and Environmental Engineering,
University of Iowa
President of Korean-American Scientists and Engineers Association (KSEA)

2. Disclaimer
The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

3. University of Iowa in Iowa City

4. Global Warming Grinnell Glacier, Glacier National Park, Montana 1911
2000

5. Since 1979, more than 20% of the polar icecap has melted!

6. Climate Change is Real!

7. First Modern Asphalt Facility
Built in 1901 by Warren Brothers in East Cambridge, Massachusetts
RAP Summit held on October 9, 2008 Maximizing RAP Use - Brock NAPA website

8. Current Asphalt Plants in United States
About 4,000 asphalt mixing plants
Mostly drum mix plants
Produces 500 million tons of HMA
Iowa Plant

9. Mixing Temperatures of HMA
Grade
HMA Plant Mixing Temperature, °C
Range
Midpoint
PG 58-28
127 ~ 154
140
PG 64-22
129 ~ 160
144
PG 70-22
138 ~ 165
152
PG 76-22
140 ~ 168
154

10. Too High Temperature of Asphalt Mix
During the past century, the asphalt industry has been concerned about keeping the temperature of asphalt mix high enough for adequate coating, placement, and compaction.
An answer to the problems in coating and compaction has been to raise the temperature of asphalt mix.
Now, for better performance and the environment, a new approach is to lower the temperature of asphalt mix: Warm-Mix Asphalt (WMA), a window to the future.
One of the most important factors is the mat temperature.
Too cold and the mix cannot be compacted - too hot and the mix will not support the rollers.

11. Worker’s Exposure to Asphalt Fumes
About 4,000 asphalt plants and 7,000 paving contractors employ nearly 300,000 workers in the United States.
In 1977, the National Institute for Occupational Safety and Health (NIOSH) recommended that workers should not be exposed to airborne particulates at a concentration greater than 5mg/m3 during any 15-minute period.
NIOSH concluded that the collective data currently available from studies on paving asphalt provided insufficient evidence for an association between lung cancer and exposure to asphalt fumes during paving.
다핵방향족탄화수소
Asphalt fumes and PAHs at the HMA job site were below the current acceptable exposure limits.

12. Exposure of Workers to Emissions Working at HMA and WMA Job Sites
(Ruhl 2004)

13. Which Picture Represent WMA Construction Sites in Iowa?

14. WMA Plants Reduce Greenhouse Gas
The U.S. Environmental Protection Agency (EPA) issued a rule that was designed to reduce SO2 by 70% and NOx emissions by 60% by 2015.
Some state and local governments require that HMA plants in some ozone sensitive areas limit asphalt production to a certain number of hours per week.
WMA plants would reduce CO2 and SO2 by 30% to 40%, volatile organic compounds (VOC) by 50 percent, CO by 10% to 30%, NOx by 60% to 70% and dust by 20% to 25%.
EAP (2006); Newcomb (2007); Ruhl (2004); D’Angelo (2008)

15. WMA Saves Energy Cost Compared with HMA
Iceland
Honolulu, HI
Joliet, IL
Fuel source
No. 2 Fuel oil
Diesel
Natural gas
Fuel to make 1 ton
of HMA
2-3 gallons
therms
Fuel Cost
$2.50/gal
$ /gal
$ /therm
Fuel Cost to make
1 ton of HMA
$5.00-$7.50
$4.40-$9.00
$1.75-$2.80
Electricity to make
8-14 kWh
Electricity Cost
$0.02/kWh
$0.1805/kWh
$0.0445/kWh
Average energy
cost for 1 ton of HMA
$5.15-$7.78
$5.84-$11.53
$2.11-$3.44
20% savings with WMA
$1.00-$1.50
$0.88-$1.80
$0.35-$0.56
50% savings with WMA
$2.50-$3.75
$2.20-$4.50
$0.88-$1.40
Ólöf Kristjánsdóttir (2007)

16. WMA Technology Category WMA Additive Company U.S. Project Organic
Sasobit®
Asphaltan®
Licomont BS-100
Cecabase RT®
LeadCap
Sasobit
Romonta
Clariant
Ceca
Kumho
Yes
N/A
Foaming
Advera®
Aspha-Min®
Low Energy Asphalt
Double-Barrel®Green
Ultrafoam GX
Terex®WMA System
Aquablack Warm Mix Asphalt
WAM-Foam
Eurovia
PQ Corporation
McConnaughay Tech.
Astec
Gencor
Terex
Maxam Equipment Inc
Kolo Veidekke, Shall
Chemical
Evotherm J1
RedisetTM WMA
MeadWestVaco/Mathy
Akzo Nobel

17. WMA Additives Selected for Laboratory Evaluation at the University of Iowa
Organic Additives:
CECABASE RT®, Sasobit®
Foaming Additives:
Asphalt-min®, Advera WMA
Chemical Additives:
Evotherm J1, RedisetTM WMX

18. Evaluation of WMA Products in Laboratory
Six WMA Mixtures:
CECABASE RT®, Sasobit®, Asphalt-min®, Advera WMA, Evotherm J1, and RedisetTM WMX.
Control WMA Mixture and HMA Mixture
Temperature
Maximum Specific Gravity
Bulk Specific Gravity
Air Void
Indirect
Tensile Strength
Test
Moisture Sensitivity
Test
Dynamic Modulus
Test
Repeated
Load
Test

19. Mixing Method and Dosage Rate of WMA Additive
Process
Dosage Rate
CECABASE RT®
Wet
0.40% of binder weight
Sasobit®
Dry
1.50% of binder weight
Asphalt-min®
0.30% of mixture weight
Advera WMA®
0.25% of mixture weight
Evotherm J1®
0.50% of binder weight
RedisetTM WMX
2.00% of binder weight

20. Mix Design Parameters Aggregates
Nominal Maximum Aggregate Size of 19.0 mm
Ndesign
86 gyrations (for 3 million ESAL)
Asphalt Content
5.5% using PG 64-34
Aggregate Heating Temp.
125°C for WMA
135°C for HMA
Asphalt Heating Temp.
149°C for both WMA and HMA

21. Mixing and Compaction Temperatures of WMA Mixtures

22. Density of WMA Mixtures

23. Air Voids of WMA Mixtures

24. Moisture Sensitivity of WMA Mixtures

25. Asphalt Material Performance Testing (AMPT) Equipment was used to Measure Dynamic Modulus and Flow Number

26. Dynamic 4.4° C

27. Dynamic 21.1° C

28. Dynamic 37.8° C

29. Master Curves of WMA Mixtures

30. Flow Number of WMA Mixtures at 45° C 138 kPa

31. Ranking of ITS, TSR, Dynamic Modulus, and Flow Number of WMA Mixtures
Type of Mix
Ranking
Average
Score
Indirect Tensile Strength
Tensile Strength Ratio
Dynamic Modulus
Flow Number
CECABASE RT® 9 5 8
7.75
Sasobit®
(wet process) 3 6 1 2
(dry process) 4
2.75
Aspha-min® (powder) 10 -
9.5
Aspha-min® (granular) 7
7.25
Advera WMA
Evotherm J1
3.75
RedisetTM WMX
3.25
Control WMA
Control HMA
3.5

32. Summary and Conclusions
Pavement is expected to perform better because the asphalt is not aged.
Working environment will be better for construction workers with a lower amount of asphalt fumes.
Based on the limited test results, Sasobit®, Evotherm J1, and RedisetTM WMX additives are effective in producing WMA mixtures in the laboratory that are comparable to HMA mixtures.
In the future, the majority of asphalt mixtures will be produced at a lower temperature than today.

33. Better Performance
WMA
Happier Workers
Better Environment

34. Future Research
Lime and Anti-stripping Additives should be considered for WMA to improve the moisture susceptibility.
To predict the rutting performance under moisture, Hamburg Wheel Tracking test should be performed.
More test sections using WMA should be constructed adjacent to HMA.

35. Cool-Mix Asphalt: A Door to a Better Road Phase 2
Coming in Fall 2012 near You from MATC
Application of CMA with LEADCAP at 115°C in Iowa City

36. Questions
Why should WMA be used instead of HMA?
How can WMA be adopted quickly in practice?
How to evaluate WMA for implementation?

37. Dr. Yongjoo Kim, Anand Sampath
CREDITS
Dr. Yongjoo Kim, Anand Sampath
Nishant Sheth, Jeremy Purvis, David Blanco
Korea Institute of Construction Technology (KICT)
Kumho Petrochemical Ltd.
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