Warm Mix Asphalt - Paving the Green Way
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Transcript of Warm Mix Asphalt - Paving the Green Way
WARM MIX ASPHALT PAVING THE GREEN WAY
Shu Wei GohZhanping You
Meor Othman Hamzah
Presentation Outline
• Warm Mix Asphalt Introduction• WMA Field Trial• Laboratory Evaluation• Summary and Conclusion
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?
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
WMA Field Trial
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
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
Mixture Cooling time
0 5 10 15 20 25 30 35 40 45120
130
140
150
160
170
180
Time (minute)
Tem
per
atu
re (
Cel
siu
s) HMA, approximate 7 minutes traveling time
WMA, approximate 7 minutes traveling time
Calculated using MultiCool Program
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.
Stack Emission Results
NOX VOC CO2 Fuel Usage-40%
-30%
-20%
-10%
0%
10%
20%
Per
cen
t In
crea
se/ R
edu
ctio
n (
%)
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
WMA Construction at Iron Mountain, MI
WMA Laboratory Testing
Laboratory Evaluation
• Volumetric Properties• APA Rutting• Dynamic Modulus Testing• Tensile Strength Ratio (TSR)
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
Volumetric Properties
Description HMA WMA
Maximum Specific Gravity, Gmm 2.573 2.569
Bulk Specific Gravity (Gmb) at the
end of Compaction2.441 2.455
Air Void Level 5.13% 4.45%
Asphalt Binder Content 5.52% 5.52%
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
APA Rutting Results
0 1000 2000 3000 4000 5000 6000 7000 8000 90000
2
4
6
8
10
12
14
HMAWMA
Cycle Number
Per
man
ent
Def
orm
atio
n (m
m)
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
Dynamic Modulus Test Results
0.00000001 0.000001 0.0001 0.01 1 1000
5000
10000
15000
20000
25000
Reduced Frequency
Dyn
amic
Mod
ulu
s (M
Pa) WMA
HMA
-10 0 10 20 30 40 50-6
-5
-4
-3
-2
-1
0
1HMA Shift Fac-tor
Temperature (Celsius)
Sh
ift
Fac
tor
Tensile Strength Ratio (TSR)
16.4 21.4 26.4 31.4 36.4 41.4 46.4 51.4 56.40
100
200
300
400
500
600
Time (Sec)
Ten
sile
Str
ess
(KP
a)
Tensile Strength Ratio
1.5% Sasobit (WMA) Control (HMA)0
100
200
300
400
500
600
700
520
609
442
532
Dry Moist
Ten
sile
Str
engt
h (K
Pa)
Ratio: 0.85±0.05
Ratio: 0.87±0.05
HMA vs WMAAfter 2 years of Serviceability
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
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
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.
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.
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.
Question?Shu Wei Goh, PhD.
Asphalt Research Laboratory Testing
Dynamic Modulus Four Point Beam Fatigue
APA Rutting Indirect Tension
Flow Number
Gyratory Compactor
Direct Tension TestModified Asphalt BBR
Rotational Viscometer
Dynamic Shear Rheometer
Rutting, fatigue cracking, and low temperature cracking; moisture damage and reflective cracking; binder’s creep stiffness and rheological properties