use of evotherm for asphalt rubber paving applications€¦ · use of evotherm for asphalt –...
TRANSCRIPT
Use of Evotherm for Asphalt – Rubber Paving Applications
RPA 2012 Annual Meeting
February 17th, 2012
2
Outline
• Current state of practice with WMA
• FHWA perspective
• What is Evotherm
• Benefits of using Evotherm with AR • Environmental benefits
• Constructability benefits
• Performance benefits
• Summary
3
Background
4
Why Warm-Mix ?
• Since the ’70’s, fuel costs have nagged the asphalt paving industry.
In 1997, the Kyoto Protocol (read international law) was adopted by most nations to reduce CO2 & other GHG’s.
For decades, the asphalt industry has been in a protracted controversy regarding the health effects of exposure to fumes.
5
Why Warm-Mix ?
• Since the ’70’s, fuel costs have nagged the asphalt paving industry.
• In 1997, the Kyoto Protocol (read international law) was adopted by most nations to reduce CO2 & other GHG’s.
For decades, the asphalt industry has been in a protracted controversy regarding the health effects of exposure to fumes.
Signatories in green.
Countries with 0% reduction targets for
2008-2012 in red.
6
Why Warm-Mix ?
• Since the ’70’s, fuel costs have nagged the asphalt paving industry.
• In 1997, the Kyoto Protocol (read international law) was adopted by most nations to reduce CO2 & other GHG’s.
• For decades, the asphalt industry has been in a protracted controversy regarding the health effects of exposure to fumes (blue smoke).
7
Why Warm-Mix ?
The IARC results were disseminated across the globe in the
industrial hygiene literature.
They stoked a fire in
the U.S. & EU asphalt
industries.
8
FHWA Perspective
9
FHWA Perspective
Implementation of warm-mix in the US is proceeding rapidly
10
What is Evotherm
• The specialty surfactants improve the lubricity of the binder
• Workability and compactability are enhanced
• Surfactants are also adhesion promoters, improve resistance to moisture damage
100
200
300
400
500
600
180 220 260 300
To
rqu
e (
in-lb
)
Temp. (F)
Workability of PG76-22 Dense-Graded Mix Containing 25% RAP
HMA
0.6% Evotherm
• Surfactant based, chemical additive package
• Added to the bitumen @ 0.3 – 0.7% w/w
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Evotherm Usage
In 2005, there
were only four
EVOTHERM
pavements in
the U.S.A.
12
Evotherm Usage
EVOTHERM Used
EVOTHERM Used & DOT Approved
No cited use of EVOTHERM
5 X 3 70 70 70
44
78
37
35
75
40
90
13
Benefits of Using Evotherm Warm Asphalt Additive
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Benefits of Evotherm
• Environmental benefits
• Reduced emissions
• Reduced fuel consumption
• Constructability benefits
• Improved compaction
• Extended haul / season
• Reduced thermal segregation
• Performance benefits
• Improved resistance to deformation – Rutting and cracking
• Improved resistance to moisture damage
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Environmental Benefits
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Lower Emissions
Hot Mix
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Reduced Emissions
HMA Control
EVOTHERM
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Reduced Plant Emissions
Hot Mix @ 155 °C Evotherm Warm-Mix @ 120 °C
19
Lower Stack Emissions with Evotherm compared to HMA
200 °F Evotherm, 310°F HMA control
-90%
-80%
-70%
-60%
-50%
-40%
-30%
-20%
-10%
0%
Fuel CO2 CO SO2 Nox TPM
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Reduced Emissions
Mexico City municipal government owns & operates two mix plants, which
now produce Evotherm mix 100% of the time (one of many measures in the city to reduce smog).
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Reduced Emissions
22
Constructability Benefits
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Constructability Benefits
• Improved compaction
• Long haul distances and extended paving seasons
• Quicker opening to traffic
• Compaction of stiffer mixes (more crumb rubber)
• Reduced thermal segregation of warm-mixes
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Improved Compaction
4
4.5
5
5.5
6
6.5
7
7.5
8
8.5
60 70 80 90 100 110 120 130 140 150 160
Compaction Temp (deg C)
Air
Void
s (
%)
Evotherm
HMA
Evotherm
HMA
Roughly 30ºC
difference is
maintained between
the Evotherm and
the HMA curves
across the range
of compaction
temperatures.
30ºC Difference
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Improved Compaction
12.5mm asphalt rubber gap graded mixes. HMA prepared @ 165C;
WMA prepared @ 135C
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Improved Compaction
Improved
Compactability Extended Haul Distances
Slower
Heat loss
Expanded Season /
Cold Weather Paving
Better in-place density
Improved Thin-Lift
Capabilities
Higher CRM Use
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Ability to Compact Stiffer Mixes
HMA
+ 20%RAP
EVO
+ 20%RAP
EVO
+ 28%RAP
EVO
+ 35%RAP
Penetration (mm)
Viscosity (cP)
Ductility (mm)
DSR @64C (kPa)
MSCR
DSR @ 70C (kPa)
BBR -12C
29
25920
38
7.35
26
3.48
0.394
39
16087
79
4.39
42
2.11
0.437
32
16738
54
5.74
37
2.91
0.406
28
23470
42
7.56
32
3.59
0.393
Possibility of adding more crumb rubber ??
28
Thermal Segregation
Associated with poor pavement performance.
Resists adequate compaction even after aggressive rolling
Higher permeabilities due to lower density
Lower shear strength
Increased binder oxidation
Reduced life of the road
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62 Deg Difference
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24 Deg Difference
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Constructability Benefits - Examples
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Constructability Benefits - Examples
33
Constructability Benefits - Examples
• January 2011
• Low ambient temperatures (4 – 6 ̊C)
• 12.5mm rubberized dense graded mix
• 2” thick lift
• ~130 ̊C Production temperatures
• ~90 ̊C breakdown temperature
National Highway – 10; Delhi – Rohtak, India
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NH – 10; India
WMA
HMA
35
Performance Benefits of Evotherm Warm-mixes
36
Performance Benefits
• Resistance to rutting
• Resistance to moisture damage
• Reduced cracking potential and increased fatigue life
• Extended binder life
37
Tandem-wheel truck tire,
40kN (9000 lb) load;
Pavement temperature is
50 ± 4°C at 50 mm below surface
Research conducted by David Jones, University of California Pavement
Research Center, Davis, California, for California Transportation Dept.
CalTrans – HVS Study
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CalTrans Heavy Vehicle Simulator
0
2
4
6
8
10
12
14
0 50,000 100,000 150,000 200,000 250,000 300,000
Tota
l R
ut
(mm
)
Number of Load Repetitions
600FD
602FD
39
TTI Overlay Tester Results - Granite
29 54108
41 58
841
634593
321
597
0
100
200
300
400
500
600
700
800
900
Cycle
s t
o F
ail
ure
Hot Mix
Evotherm
* Test stopped
*
*
40
TTI Overlay Tester Results - Limestone
31 21 20 30 26
419
490
345 334
397
0
100
200
300
400
500
600
Cycle
s t
o F
ail
ure
Hot Mix
Evotherm
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Longer Lasting Roads
Hundreds of projects; > 10,000 miles
10+ independent studies
More than 20 DOT Evaluations
Projects in 40 states, 8 provinces, 10 countries
20+ million ESAL’s on NCAT Test Track with less than 2 mm of rutting
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Resistance to Moisture Damage
Evotherm has been approved as a liquid anti-strip
• Alabama • Florida • Illinois
• Iowa • Missouri • North Carolina
• Tennessee • Virginia • Washington
Enables replacement of lime or liquid anti-strip in the mix design while achieving best-in-class warm mix asphalt
performance.
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Resistance to Moisture Damage
44
Conclusions
45
Evotherm Difference
Easy to Use
• Any mix plant
• No equipment to purchase or maintain
• Drop-in laboratory evaluations
Lowest Temperatures
Proven Performance
46
Evotherm Difference
Easy to Use
Lowest Temperatures • Reduced thermal segregation
• Lower emissions
• Reduced fuel consumption
• Long hauls
• Extended season
Proven Performance
47
Evotherm Difference
Easy to Use
Lowest Temperatures
Proven Performance • Improved Compaction
• Increased RAP Content
• Longer binder life
