Field Evaluation of Warm Mix Asphalt - A technology that allowed the producers of Hot-Mix Asphalt (HMA) pavement material to lower the temperatures at which the material is mixed and placed on the road.
2. Presentation Outline
• Warm Mix Asphalt Introduction
• WMA Field Trial
• Laboratory Evaluation
• Summary and Conclusion
3. Hot Mix Asphalt
• What is Warm Mix Asphalt (WMA)?
– A technology that allowed the producers of Hot-Mix
Asphalt (HMA) pavement material to lower the
temperatures at which the material is mixed and
placed on the road.
• Available Technologies:
– RH-WMA®, Aspha-min®, Advera WMA, Sasobit®,
Evotherm®,etc.
Warm
The wave of Future?
4. Why Warm Mix Asphalt?
• Reduce Production and Laydown Temperature
• Reduce Emissions
• Reduce Fuel Costs
• Reduce Aging of Binder
• Decrease Wear and Tear of Equipment
• Increase Production Rates
• Better Compaction
• Maximization of Asphalt Recycling Rate
While achieving the same or better density
6. Project Information
• Project Location: Spread Eagle, Wisconsin, USA
• Asphalt Binder used: PG58-34
• Design Traffic level: 3 millions ESALs
• HMA
– Compaction Temp: 150˚C
• WMA made with 1.5% Sasobit® (5E3)
– Compaction Temp: 127˚C
7. Project Location
Description Value
Ambient Air
Temperature (ºC)
7.66
Surface Temp.
(ºC)
11.61
Average Wind
Speed (km/h)
8.05
Latitude (Deg.
North)
88.08
Travel Distance: ~8-10km
8. Mixture Cooling time
120
130
140
150
160
170
180
0 5 10 15 20 25 30 35 40 45
Temperature(Celsius)
Time (minute)
HMA, approximate 7 minutes
traveling time
WMA, approximate 7
minutes traveling time
Calculated using MultiCool Program
9. WMA Construction at Iron Mountain, MI
Warm Mix Asphalt Hot Mix Asphalt
Reference: Goh, S. W., and You, Z. (2008). "Warm Mix Asphalt using Sasobit®: A Brief Field and
Laboratory Experience." Mid-Continent Transportation Research Forum 2008, Wisconsin, Madison.
10. Stack Emission Results
-40%
-30%
-20%
-10%
0%
10%
20%
NOX VOC CO2 Fuel Usage
PercentIncrease/Reduction(%)
Reference: Graham C. Hurley, Brian D. Prowell and Andrea N. Kvasnak (2009), Michigan Field Trial of
Warm Mix Asphalt Technology: Construction Summary. NCAT Report No. 09-10, Auburn University
14. Material Preparation:
Asphalt Mixture Performance Testing
• Testing Sample (Collected from Asphalt Plant at Iron
Mt., MI):
– Asphalt Binder used: PG58-34
– SuperpaveTM Gyratory Compactor: 86 gyrations
– HMA (5E3) – Compacted at 150◦C
– WMA made with 1.5% Sasobit® (5E3) - Compacted at
127◦C
Sieve Size (mm) 12.5 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075
Percent Pass, % 100 99.1 75 55.9 41.3 27.5 14.5 7.5 5.5
AC, % 5.5
15. Volumetric Properties
Description HMA WMA
Maximum Specific Gravity, Gmm 2.573 2.569
Bulk Specific Gravity (Gmb) at the
end of Compaction
2.441 2.455
Air Void Level 5.13% 4.45%
Asphalt Binder Content 5.52% 5.52%
16. APA Rutting Test
• Asphalt Pavement Analyzer:
– The purpose of this test is to
evaluate the rut resistance of the
asphalt mixture and the rut depth
was measured using the Asphalt
Pavement Analyzer machine.
• Testing Parameters:
– 8000 Cycles
– 58C (136 ˚F)
– 100 lbs
18. Dynamic Modulus Test
• Determined by applying
sinusoidal vertical loads to
cylindrical samples while
measuring the deformation
• Tested ranged from 0.1 to 25
HZ
• Temperature tested:
– -5C
– 4C
– 13C
– 21.3C
– 39.2C
23. Sasobit® and Control Test Sections
after Two Years of Traffic
Reference: Graham C. Hurley, Brian D. Prowell and Andrea N. Kvasnak (2009), Michigan Field Trial of
Warm Mix Asphalt Technology: Construction Summary. NCAT Report No. 09-10, Auburn University
Description HMA Sasobit®
Rut Depth (mm) 1.4 0
Total Length of Crack (ft.) 3 46
Density (% Gmm) 97.3 95.7
24. Conclusions
• Emissions from WMA were significantly reduced
compared to HMA production.
• Early performance indicates that Sasobit® WMA can
be successfully used in cold weather climates.
• Based on emission stack testing, a decrease in asphalt
stack emissions and fuel usage was determined during
the production of WMA. An increase in CO and
VOCs for the WMA indicates the need for additional
burner tuning to fully combust the burner fuel
25. Conclusions
• WMA has a higher E* throughout all the
temperatures and frequencies. Mixtures with higher
E* generally have a lower rutting potential and this
concluded that WMA has more resistance to rutting.
• Based on the tensile strength ratio result, it was found
the moisture susceptibility of WMA was compatible
with HMA. However, it was found that the tensile
strength of WMA is lower than HMA.
26. Conclusions
• Based on the APA testing, the field produced WMA
made with 1.5% Sasobit® (compact at 23 ˚C lower
than HMA) has similar rutting potential compared to
control HMA.
• Based on the field evaluation (after 2 years of
serviceability), it was found that WMA made with
Sasobit® has better rutting resistant. However, it was
found the additional Sasobit® decreased the crack
resistance of pavement.
27. Acknowledgements
The research work was partially sponsored by the Federal
Highway Administration (FHWA) through Michigan
Department of Transportation (MDOT).
The authors also acknowledge the funding support from the
United States Department of Transportation through the
University Transportation Center for Materials in Sustainable
Transportation Infrastructure at Michigan Technological
University.
29. Asphalt Research Laboratory Testing
Rutting, fatigue cracking, and low
temperature cracking; moisture damage and
reflective cracking; binder’s creep stiffness
and rheological properties