Transcript Industry Perspective—Polymer Modified Asphalts

Benefits of Modified Asphalts
John Duval, P.E.
Oregon Asphalt Conference
March 8, 2006
Modified Binder Use to Increase
It is likely that modified binders
represent as much as 15% of the total
annual tonnage of asphalt binder used
in the United States; this percentage is
expected to increase in the coming
decade
NCHRP Report 9-10 (2001)
AI Member Companies
Overview
•
•
•
•
Commonly used asphalt modifiers?
What is the benefit of asphalt modifiers?
PG PLUS Specifications
The Path to PG PLUS Specifications
– How did other states arrive there?
• Finally—A way to Quantify the Benefit of
Modified Asphalt Binders
• Summary/Recommendations
Types of Asphalt Modifiers
Extenders
• Sulfur
• Lignin
Sulfur
Extended
Asphalt?
Extenders are typically
cheaper than asphalt and
replace asphalt binder
Fibers
• Natural
– Rock Wool
– Cellulose
• Man-Made
– Polypropylene
– Polyester
– Fiberglass
Fibers can be used to increase
asphalt stiffness, but are
primarily used to control
“drain-down” in open-graded
mixtures
Polymers
poly  mer
“many parts”
Image courtesy Infrapave
• Elastomers
• Plastomers
• Combinations
Elastomers
• Natural Latex Rubber
• Synthetic Latex
• Block Copolymer
– Styrene-butadienestyrene (SBS)
• Reclaimed Rubber
Image courtesy Injectec.com
– Styrene-butadiene
(SB)
PVC Pipe
Image courtesy slpipe.com
Plastomers
• Polyethylene
• Polypropylene
• Ethyl-vinyl-acetate
(EVA)
• Polyvinyl-chloride
(PVC)
EVA is a plastic that is
used to create stiffer
insoles for your shoes
Image courtesy cyclingfitness.com
Others
• Oxidants / Antioxidants
• Hydrocarbons
– Asphalt Blending (from
different Crude Oils)
– Lake Asphalt
– Recycling/Rejuvenating Oils
• Antistrip Agents
– Lime
– Liquid (Amines)
Polyphoshoric Acid (PPA)
• PPA is a liquid mineral
polymer
• PPA be used alone or in
conjunction with polymers
• PPA can improve high
temperature stiffness
• PPA modification does not
oxidize the asphalt binder
• Care should be taken to
avoid neutralization of
amine-based liquid
antistrip chemicals
IS-220
Why are Asphalt Modifiers
being used?
SR2 near Wenatchee, WA
Plastic Deformation
(Rutting)
SR2 near Davenport, WA
Low Temperature
Cracking
Performance Graded Asphalt
Grading System Based on Climate
PG 70-22
Performance
Grade
Average 7-day
max pavement
design temp
Min pavement
design temp
PG Binder Grades
PG 64-22 Probably Unmodified
PG 70-28 Probably Modified
This is
the
benefit
of the
modifier
The Rule of 90
PG 70-28
PG 64-22
-40 -30 -20 -10
0 10 20 30 40
TEMPERATURE ºC
50
60
70
80
PG PLUS Specifications
Agency Perspective
Many Highway Agencies have
developed PG PLUS specifications
The intent is to ensure that the
preferred modifier is used
Industry Perspective
Encourage Agencies to use
performance specifications
This allows suppliers to innovate
and compete in the marketplace to
earn a profit
States with PG PLUS Specs
Ductility
ER
PA
ER
ER
Ductility,
TT & ER
TT & DT ER & TT
ER
& FD
ER
ER
ER
PG + modifier
PG
Source: Asphalt Institute ER 215 (2005)
ER &
TT
ER &
PA
ER
SB/SBS
Required
FD &
ER
ER
ER
SB/SBS
Required
ER
FD
ER
ER & PA
PA
PA
ER-Elastic Recovery
FD-Force Ductility
TT-Toughness &
Tenacity
PA-Phase Angle
Research on Modified Binders
•
•
•
•
•
NCHRP 9-10 (Prof. H. Bahia)
FHWA Accelerated Loading Facility
European Studies
Industry Research
State DOT research
– Nevada DOT I-80 Study (Prof. P. Sebaaly)
– Nevada DOT Construction Variability Study
(Prof. P. Sebaaly)
Source:Sebaaly et al. RR 1393-5, (2003)
Nevada DOT (2003)
The Path to PG PLUS
(Its shorter than you might think)
Courtesy of Tennessee DOT
Courtesy of Tennessee DOT
Mississippi DOT
“PG 76-22 or PG82-22 and shall be made by adding a polymer
modifier to a PG 67-22 or lower grade asphalt. Polymer shall
be SBS, SBR, or equal approved by Engineer.”
Mississippi DOT Std Spec Section 702.02
“We make the suppliers start with the PG 67-22, then modify
that to get the PG 76-22.”
Jimmy Brumfield, Mississippi DOT
Polymer adds between $3 to $5 per ton of mix, which
increases the cost of mix to about $38 to $42 per ton.
“Working with Polymers,“ Better Roads, 2004
Finally—A way to
Quantify the Benefit
of Modified Asphalt Binders
Quantifying the Effects
of PMA for Reducing Pavement Distress
IS 215
ER 215
This study (published in
Feb 2005) uses national
field data to determine
enhanced service life of
pavements containing
polymer modified binders
versus conventional
binders. The data is from
a variety of climates and
traffic volumes within
North America.
Study Objectives
• Quantify the effect of using PMA as
compared to conventional-unmodified
HMA mixtures in terms of:
– Increasing pavement life
– Reducing occurrence of distresses
• Identify conditions that maximize effect of
PMA to increase HMA pavement & overlay
life.
Field Test Sections
• FHWA’s LTPP
– SPS-1; SPS-5; SPS-6; SPS-9
– GPS-1; GPS-2; GPS-6; GPS-7
• M.T.Ontario Modifier Study
• Accelerated Pavement Tests
–
–
–
–
–
FHWA ALF
NCAT Test Track
California HVS Studies
Ohio Test Road
Corp of Engineers
Locations of Test Sections
- PMA and Unmodified Companion
Not all sites
located on map.
Companion Sections—Montana
HMA Overlay (w/ PMA)
HMA Overlay
HMA
HMA
Soil-Aggregate Base
Soil-Aggregrate Base
Soil-Aggregate Base
Soil-Aggregate Base
Companion Sections—Montana
HMA Overlay (w/PMA)
HMA
HMA Overlay
Soil-Aggregrate Base
HMA
Soil-Aggregate Base
Soil-Aggregate Base
Soil-Aggregate Base
Rut Depths on Companion
Sections, inches
Direct Comparisons – Rutting
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
Rut Depths on PMA Sections, inches
1
1.2
Transverse Cracking - Companion
Sections, ft.
Distress Comparisons –
Transverse Cracking
500.0
450.0
400.0
350.0
300.0
250.0
200.0
150.0
100.0
50.0
0.0
0.0
100.0
200.0
300.0
400.0
Transverse Cracking - PMA Sections, ft.
500.0
Distress Comparisons –
Fatigue Cracking
Fatigue Cracking - Companion
Sections, %
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0.00
20.00
40.00
60.00
Fatigue Cracking - PMA Sections, %
80.00
Mechanistic-Empirical Analysis
• Use M-E distress prediction models from
new 200x Pavement Design Guide for:
– Fatigue Cracking
– Rutting
• Damage indices computed using factorial
cell specific calibration
• Compare damage indices to actual
distress measurements for both PMA and
unmodified sections
Summary of Expected Increase in Service Life,
Years, Based on M-E Damage Based Analysis
Site Factor
Condition Description
Added Life
Non-expansive, coarse soils
5-10
Expansive and plastic soils (PI>35)
2-5
Frost Susceptible in cold climate
2-5
Deep
5-10
Water Table
Shallow; adequate
& Drainage
Shallow; inadequate
5-8
Foundation
Existing
Pavement
Condition
HMA
PCC
0-2
Good
5-10
Poor-extensive cracking
1-3
Good
3-6
Poor-faulting & cracking
0-2
Summary of Expected Increase in Service Life,
Years, Based on M-E Damage Based Analysis
Site Factor
Condition Description
Climate; Temp. Hot
Fluctuations
Mild
Cold
Traffic, Truck
Volumes
Low
Moderate
High
Hot Extremes
Added Life
Cold Extremes
5-10
2-5
3-6
Intersections
Thoroughfares
Heavy Loads
5-10
3-6
5-10
5-10
5-10
Generic LCCA Strategy/ Timeline and
Revised PMA Timelines Based on Results
Years
Conv.
Struct.
PMA
Surface
2-4 in.
PMA
Full
Depth
5
10
15
RM
20
RM
MillFill
HMA
OL
RM
25
30
35
RM
MillFill
RM
HMA
OL
RM
HMA
OL
RM
RM
HMA
OL
RM
MillFill
40
RM
MillFill
Life Cycle Cost Analysis
Initial Construction
Net
Present
Value
Rehabilitation
Maintenance
0
Time
Salvage
Assumptions for Following Examples
14.5" HMA Pavement
Prices
Wearing (PG 64-22)
Wearing (PG 76-22)
Binder (PG 64-22)
Binder (PG 76-22)
Base (PG 64-22)
Base (PG 76-22)
Milling
HMA Patching
Interest Rate: 4%
Analysis Period = 40 yrs.
$36/ton
$41/ton
$35/ton
$40/ton
$35/ton
$40/ton
Quantities (per mile)
Mainline: 2-lanes @ 12 ft ea.
Shoulders: 1 @ 10 ft and 1 @ 4 ft
No User Costs Considered
$1.97/sy-in
$2.24/sy-in
$1.91/sy-in
$2.19/sy-in
$1.91/sy-in
$2.19/sy-in
$1.40/sy
$36/sy
14,080sy
8,212sy
References
Prices from Maryland's "Pavement Selection Process"
Maintenance from "Pa DOT Pub. 242, Pavement Policy Manual"
Performance Scenarios are Examples from "Quantifying Effects of PMA ..."
EXAMPLE 1, Unmodified All Layers
Present Worth Analysis (ln/mi) for --
LCC Unmodified)
14.5-inch section
Construction Item and/or Material
Quantity
Interest
4
Year
Unit
Cost/Unit
0
0
0
0
0
0
0
0
10" HMA Base ( 3 - 10 EAL)
2.5" HMA Binder (3 - 10 EAL)
2" HMA Wearing (3 - 10 EAL)
10" HMA Base (0.3 - 3 EAL)
2.5" HMA Binder (0.3 - 3 EAL)
2" HMA Wearing (0.3 - 3 EAL)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
14080
14080
14080
8212
8212
8212
1
1
sy
sy
sy
sy
sy
sy
ls
ls
$
$
$
$
$
$
19.10
4.78
3.94
19.10
4.78
3.94
$14,264
$34,109
10
10
10
10
10
Deep Patch 1% (mainline)
Mill 2" (mainline)
2" hma overlay (mainline)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
141
14080
14080
1
1
sy
sy
sy
ls
ls
$
$
$
$
$
36.00
1.40
3.94
1,846.05
4,414.48
18
18
18
18
18
18
18
18
18
18
Mill 2"
Deep Patch 3% (mainline)
#60 scratch course
2.5" hma overlay (binder)
2" hma overlay (wearing)
#60 scratch course
2.5" hma overlay (binder)
2" hma overlay (wearing)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
22292
422
422
14080
14080
246
8212
8212
1
1
sy
sy
ton
sy
sy
ton
sy
sy
ls
ls
$
$
$
$
$
$
$
$
1.40
36.00
36.00
4.78
3.94
36.00
4.78
3.94
$6,091
$14,566
28 Same Scenario as Year 10
1 ls
$86,524
34 SameScenario as Year 18
1 ls
$285,492
20 Total Annual Maintenance ($1825/yr)
40 yr
$
1,825.00
Total
Current Price
Yr.$268,928
$67,302
0 $55,475
$156,849
$39,253
$32,355
$14,264
$34,109
10 $5,076
$19,712
$55,475
$1,846
$4,414
$0
$31,209
$15,192
$15,192
$67,302
$55,475
$8,856
$39,253
$32,355
$6,091
$14,566
$0
$86,524
$0
$285,492
$0
$73,000
$0
Present Worth
18
28
34
PW
$268,928
Activity
$67,302
10”
Base
$55,475
$156,849
2.5”
Binder
$39,253
$32,355
2”
Wearing
Cost,$ NPW,$
668K
668K
$14,264
$34,109
2”$3,429
mill/fill
87K
$13,317
1%
patching
$37,477
$1,247on shoulders)
(not
$2,982
2” mill
285K
$0
$15,406
3%
patching
$7,499
$7,499
scratch
$33,222
2.5”
$27,384Binder
$4,372
2”
Wearing
$19,377
$15,971 shoulders)
(incl.
$3,007
$7,190 as yr.10
Same
87K
$0
$28,854
$0
$75,242
$0
$33,316
$0
$1,005,328
Same as yr.18
285K
Annual Maint ($1.8K/yr) 73K
Total NPW:
58K
141K
29K
75K
33K
1,005K
EXAMPLE 2, Modified Wearing Course
(top 2”, including shoulders)
Present Worth Analysis (ln/mi) for --LCC Modified Surface)
14.5-inch section
Interest
4
Year
Yr.
Construction Item and/or Material Quantity
Unit
Cost/Unit
0
0
0
0
0
0
0
0
10" HMA Base ( 3 - 10 EAL)
2.5" HMA Binder (3 - 10 EAL)
2" HMA Wearing (3 - 10 EAL)
10" HMA Base (0.3 - 3 EAL)
2.5" HMA Binder (0.3 - 3 EAL)
2" HMA Wearing (0.3 - 3 EAL)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
14080
14080
14080
8212
8212
8212
1
1
sy
sy
sy
sy
sy
sy
ls
ls
$
$
$
$
$
$
19.10
4.78
4.48
19.10
4.78
4.48
$14,541
$34,771
18
18
18
18
18
18
18
18
18
18
Mill 2"
Deep Patch 3% (mainline)
#60 scratch course
2.5" hma overlay (binder)
2" hma overlay (wearing)
#60 scratch course
2.5" hma overlay (binder)
2" hma overlay (wearing)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
22292
422
422
14080
14080
246
8212
8212
1
1
sy
sy
ton
sy
sy
ton
sy
sy
ls
ls
$
$
$
$
$
$
$
$
1.40
36.00
36.00
4.78
4.48
36.00
4.78
4.48
$6,368
$15,228
34 SameScenario as Year 18
20 Total Annual Maintenance ($1825/yr)
1 ls
40 yr
$298,469
$
1,825.00
Total
Current Price
$268,928
$67,302
$63,078
$156,849
$39,253
$36,790
$14,541
$34,771
$0
$31,209
$15,192
$15,192
$67,302
$63,078
$8,856
$39,253
$36,790
$6,368
$15,228
$0
$298,469
$0
$73,000
$0
Present Worth
0
Activity
Cost,$ NPW,$
PW
$268,928
10”
Base
$67,302
$63,078
2.5”
Binder
$156,849
2” $39,253
Wearing
682K
682K
18
2” mill
298K
3% patching
scratch
2.5” Binder
2” Wearing
(incl. shoulders)
147K
34
Same as yr.18
79K
$36,790
$14,541
$34,771
$0
$15,406
$7,499
$7,499
$33,222
$31,137
$4,372
$19,377
$18,160
$3,143
$7,517
$0
$78,662
$0
$33,316
$0
$940,824
298K
Annual Maint ($1.8K/yr) 73K
Total NPW:
33K
941K
EXAMPLE 3, Perpetual Pavement: Modified Wearing
Course (top 2”) and Bottom 4” of Base (incl. shoulders)
Present Worth Analysis (ln/mi) for --LCC Modified Surface & 4"Base)
14.5-inch section
Interest
4
Year
Yr.
Construction Item and/or Material Quantity
Unit
Cost/Unit
0
0
0
0
0
0
0
0
0
0
4" HMA Modified Base ( 3 - 10 EAL)
6" HMA Base ( 3 - 10 EAL)
2.5" HMA Binder (3 - 10 EAL)
2" HMA Wearing (3 - 10 EAL)
4" HMA Base (0.3 - 3 EAL)
6" HMA Base ( 3 - 10 EAL)
2.5" HMA Binder (0.3 - 3 EAL)
2" HMA Wearing (0.3 - 3 EAL)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
14080
14080
14080
14080
8212
8212
8212
8212
1
1
sy
sy
sy
sy
sy
sy
sy
sy
ls
ls
$
$
$
$
$
$
$
$
8.76
11.46
4.78
4.48
8.76
11.46
4.78
4.48
$15,115
$36,144
18
18
18
18
18
Mill 2"
2" hma overlay (wearing)
2" hma overlay (wearing)
Maint. & Protection of Traffic @2.3%
Mobilization @5.5%
22292
14080
8212
1
1
sy
sy
sy
ls
ls
$
$
$
1.40
4.48
4.48
$3,015
$7,209
34 SameScenario as Year 18
20 Total Annual Maintenance ($1825/yr)
1 ls
40 yr
$141,301
$
1,825.00
Total
Current Price
$123,341
$161,357
$67,302
$63,078
$71,937
$94,110
$39,253
$36,790
$15,115
$36,144
$0
$31,209
$63,078
$36,790
$3,015
$7,209
$0
$141,301
$0
$73,000
$0
Present Worth
0
Activity
Cost,$ NPW,$
PW
$123,341
10”
Base
$161,357
$67,302
2.5”
Binder
$63,078
2” $71,937
Wearing
$94,110
$39,253
$36,790
$15,115
$36,144
$0
$15,406
$31,137
$18,160
$1,488
$3,559
$0
$37,240
$0
$33,316
$0
$848,734
709K
709K
18
2” mill/fill
141K
(incl. shoulders)
70K
34
Same as yr.18
37K
141K
Annual Maint ($1.8K/yr) 73K
Total NPW:
33K
849K
Quantifying the Benefit
Pavement Type
Initial Cost Change#
-
NPV
Savings
1,005K
-
1) Unmodified
(resurface yr.10 and 28,
structural overlay yr.18 and 34)
669K
2) Modified Wearing
682K
+ 2.0%
941K
6.5%
709K
+ 6.0%
849K
15.5%
(structural overlay yr.18 and 34)
3) Modified Wearing & Base
(Perpetual Pavement:
resurface yr. 18 and 34)
Cost to use PMA equates to approx.
1% of initial cost per inch modified
Summary/Recommendations
• Modifiers can improve high and low
temperature properties of asphalt binders
• We are still waiting for a PG PLUS test
that is “blind” to the modifier
• AI ER 215 provides a sound method to
measure the benefit of modified asphalts in
order to make decisions based on lowest
lifecycle cost.
Summary/Recommendations
• ODOT should study the cost
and benefit of modified
asphalt mixes in Oregon
– Laboratory assessment of rut
susceptibility using Asphalt
Pavement Analyzer
– Field studies of full-scale
modified asphalt sections
subjected to actual traffic
Thank you