08 jay behnke
DESCRIPTION
Presenation by Jay Behnke of STATE Testing on RAP and RAS at the California Asphalt Pavement Association Spring Conference April 25, 2013 in Ontario, CA.TRANSCRIPT
Hey Buddy,What’ll you
have?
Jay Behnke, P.E.President
S.T.A.T.E. Testing, LLC
Dundee and Chicago, IL
Behnke Materials Engineering
Beloit, WI
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An HMA Perspective from the Land of Gangsters and Cheese
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Our Sand Box
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Pick a Good Team
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Our Team:
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Our Team:The photogenic ones…
Agencies we work for:
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1. Interest2. Initiative3.Courage 4.Available Projects5.Short Decision Tree6.Funding
Class Outline
Mix Design Basics Sustainable Technologies Performance Testing Project Examples
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Gyratory Compactor
6 in.
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% Density
Gyrations90NDESIGN
96%
(4% voids)
Gyratory Compaction
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How to Change NDESIGN
1. Aggregate Structure• More Coarse Aggregate• More Manufactured Sand• Less Natural Sand• Less dust
2. Asphalt Binder Content.
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VMA – Voids in Mineral Aggregate
“Space between the Rocks filled with Asphalt Binder and Air Voids”
Excludes Binder Absorbed into the Aggregate
Sets Minimum Binder Content for Durability
Varies with Aggregate Size.
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VMAVoids in Mineral Aggregate
11%
4%15% VMA
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Aggregate Surface Area
One inch dia. rock makes 64 - ¼ in. rocks
Sum of the ¼ in. rocks have 4X surface area.
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VMA Spec by Aggregate Size
Nom. Max.Agg. Size
Minimum VMA
AirVoids
Effective Binder
9.5 mm 15 % - 4% = 11%
12.5 mm 14 % - 4% = 10%
19.0 mm 13 % - 4% = 9%
25.0 mm 12 % - 4% = 8%
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Field VMA
Gmb Dust to AC ratio Contractor is
allowed to remove dust during production
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Field VMA: (f) % AC and Voids
Just a calculation – Uses existing values = 100 – (GMB * PS / GSB)
GMB: “d” from plant test
PS: % Stone = 100- %AC
GSB: Stone Specific Gravity from Design
e.g. = 100 – (2.415 * 0.94 / 2.687) = 15.5Watch: If AC & Voids drop below mix design
values.
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Dust Silos
IDOT requires “Positive Dust Control”
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Mel Pod – Positive Dust COntrol
Weighs Dust In and Out
Start-ups Illustrated
Test strip required for all new mixes.
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Performance Graded Binder
“PG Binder”(Asphalt Cement)
NOT “Polymer Graded”
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PG Binder Nomenclature
PG64-22Performance Grade
Average 7-day max pavement design temp C
Min pavement design temp C
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….without binder grade jumping.
2010
2012
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When to Modify?
Extreme Temperatures• Hot or Cold
Heavy Traffic• Especially Slow or Stopped
Rutting or Shoving Problem Areas Concern re: Reflective Cracking Improve Film Thickness.
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Permeability Factors Increased Density Lower Permeability Smaller NMAS aggregate Lower
Permeability (fewer interconnected voids)
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Permeability can be measured
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Permeability vs.Density and Nom. Max. Agg. Size
(NCAT)
Sustainable Options for HMA
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RAP FRAP GTR WMA RAS
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Recycled Asphalt Pavement(RAP)
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RAP Can Be Our Friend
Quality Green Economical.
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RAP Works Processed Reasonable
Proportions Designed into the
mix < 20% - Acts as
“Black Rock.”
- Superpave Research
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Binder Grade for RAP Mixes
RAP% Binder Grade≤ 20% Use Same PG Grade> 20% Use Softer Grade
e.g. PG 58-28 for PG 64-22.
FRAP - Fractionated RAP
Old – RAP was bad Then – RAP is OK Now – FRAP is great
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IL FRAP Sizes (typical)
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< #4 (0.2 in.)
#4 to 1/2 in.
> 1/2 in.
Observations - FRAP
High Quality Grindings Higher RAP % does not affect production P#4 Material useful in SMA
• Angular• Higher AC Content
Bids reflect overall savings Less segregation
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GTR - Ground Tire Rubber Modified Asphalt
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GTR-Modified Asphalt
AC modified with recycled Ground Tire Rubber (12-15%)
Substitute for polymer-modified AC
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Vestenamer Stabilizer
Why GTR?
Improved performance• Rutting• Resistance to oxidation
Green - 2,000 tires per lane mile (2 in.) $$ ≈ Polymer-modified AC Replaces anti-draindown fibers
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No Draindown
Replacement for Fibers. Open Graded Pervious SMA
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GTR is Versatile
Since 2006: Green Alleys City Streets (low
ESAL) County Roads
(medium ESAL) Tollway mainline
(high ESAL) Bridge Decks Michigan Avenue
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WMA - Warm Mix Asphalt
Lowered emissions Less fuel consumption Worker health benefits Lower temps = Reduced
oxidation Extended paving season
• Haul time• Compaction time
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Warm Mix Technologies
Chemical additives, e.g. Evotherm
Organic additives “wax”, e.g. Sasobit
Foaming –Astec Double Barrel® Green
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CDOT Warm Mix Asphalt
6000+/- tons Produced @ 230˚ F Placed down to 180˚ F Same rolling pattern No difference in
workability Reduced odor, fumes
WMA Warm Mix Asphalt + RASon the Interstate
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RASRecycled Asphalt Shingles
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2012 - RAS is the Law in Illinois
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RAS = Quality HMA Ingredient
Consistent gradation:• 100% < 3/8 in.• 93% < #4
30+% High Quality Fine Aggregate 26.4% High Quality AC 27.8% Mineral Filler
• Shoot for 1:1 ratio (dust to AC) Mineral/Organic Fibers
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High ESAL RAS
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Field Performance
No time for TRB WMA GTR High ABR FRAP RAS
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Illinois’ Performance TestHamburg Wheel
Torture Test for Stability Moisture
Resistance
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Chicagoland Hamburg Criteria
All WMA, RAS, & High-ABR mixes
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Binder # Repetitions (Chicago)
Max. Rut Depth
PG76-XX, PG70-XX 20,000
0.5 in.PG64-XX, PG58-XX, PG52-XX, PG46-XX 10,000
SMA 20,000 0.25 in
Passing the Hamburg Test
GTR RAS Manufactured Sand Harder Rock (not
Limestone) Anti-strip additive
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Direct Compact Tester
Performance Testing
Field Demonstration Projects
Research Lab Verification
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PROJECT EXAMPLES
Tollway - Warm Mix CDOT – N30 LC IL 4.75 – Friction
Course Michigan Ave
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Jane Addams Tollway WMA, HMA, FRAP, RAS
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Tollway Warm Mix Asphalt
In 2012 the Tollway was the first agency in the country to mandate Warm Mix Asphalt!!!
Tollway WMA - 2012 762,000+ total tons (Magnificent Green 56
Miles) SMA mainline
• 304,000 tons
N50 Shoulder Binder• 204,000 tons
N70 Shoulder Surface• 210,000 tons
Stabilized Subbase• 8,400 tons
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Akzo Nobel• “REDISET LQ”
MeadWestVaco• “EVOTHERM M1”
Astec, Inc.• “ASTEC WARM MIX
SYSTEMS”
AQUABlack Solutions• “MAXAM
AQUABLACK” Stansteel Asphalt
Plant Products• “STANSTEEL ACCU-
SHEAR”
CDOT manages a lot of Asphalt Paving…in a variety of locations
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CDOT by the Numbers
$600-800 Million Annual Budget(More than half from state or federal grants)
262 bridges and viaducts4,091 miles of streets (excluding Expressways)26,658 intersections (2,935 signalized)10,646,110 feet of lane striping12,145 bike racks10,997 trees planted/year59 stations and 50 miles of track owned by CDOT but operated by CTA
CDOT Typical In-House Program
2 Block increments 4 Paving crews
• 2 street / 2 alley +/- 150,000 tons / year
placed Innovative mixture(s) Purchased from local
plants Rented equipment
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9.5mm N30 LC Surface Mix(Low ESAL)
Evolving over the years Increased % FRAP Added recycled PCC Added GTR Lowered PG grades Added WMA technology Added RAS % ABR Hamburg Tested
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9.5mm N30 LC Surface Mix(Low ESAL)
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ABR PG Binder
0-22% PG 64-22
23-45% PG 58-28
46-67% PG 46-34
Recycled Material Max%
Crushed PCC &/or Coarse Aggregate
50% Total Aggregate
Fractionated RAP 40%
RAS 7.5%
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4.75mm Friction Surface
Not a “sand mix” Historically a
polymer-modified mix
RAS used as modifier.
Can be laid ¾” thick!!
HMA version of Micro Surfacing
Recycled Friction AggregateChicago Expressways: Most
surfaced with slag friction mixes and high quality AC binder.
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4.75mm Friction Surface New Specification
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AGGREGATES PERCENTAGE
Natural Sand 40% Maximum
Manufactured Sand 15% Minimum
combinedManufactured Sand from Gravel; or Steel Slag
Passing #4 portion of FRAP from Steel Slag RAP; or Steel Slag 35% Minimum
combinedFine Aggregate from Steel Slag RAP; or Steel SlagRAS 7.5% Maximum
4.75mm Friction Surface New Specification
VOLUMETRICS NDES = 50 Voids = 3.5% VMA = 18.5%
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ABR PG Binder Max. RAS0-22% PG 64-22 2.5%
23-45% PG 58-28 5.0%46-67% PG 46-34 7.5%
High ABR
4.75mm High ABR Surface 2011 Demonstration
% MIX
AC Content ABR
FRAP (1) 8% 4.8% 0.4%
FRAP (2) 30% 5.8% 1.7%
RAS 7.0% 26% 1.8%
3.9%
Design AC 8.0%
New AC 4.1%
AC Savings $28 / Ton
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50% ABR
Pulling it TogetherMichigan Avenue SMA
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Environmental Leadership Award2012 NAPA
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Examination
Given: Location Variable
Base/Subbase 300 Structures to
work around Time Constraints Green Objectives
Solve for:
1. Milling Thickness
2. Lift Thickness
3. Binder Mix
4. Surface Mix
5. Tack Coat
6. Paving Width
7. Maximum ABR
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Factors favoring Single SMA Lift
Uncertainty of Base Time Cost SMA Characteristics
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Michigan Ave SMA Mix Design
MIXTURE OIL
Quartzite 12.5mm 50%
Quartzite 9.5mm 24%
FA & Mineral Filler 3.5%
RAP < 3/8 in. 15% 0.8%
RAS 7.5% 2.0%
PG 58-28 GTR+12 6.1% 3.3%
6.1%
VOLUMETRICS NDES = 80 Voids = 3.5% VMA = 16.3% VFA = 78.5%
Torture Tested (cores)
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< 4mm rut
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Test Strip at Plant
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Paving
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Logistics & Traffic Control
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Sweeping for Prime was an Art in Itself
+ Trackless Tack/Prime Coat
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Completed in 6 consecutive nights of Paving
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Daily Temperatures
Oct-201116 17 18 19 20 21 22
High 52°Low 27°
53° 27°
57° 30°
61° 27°
62°40°
54° 31°
60° 36°
Historic Averages54°/30° 53°/29° 52°/29° 52°/28° 51°/28° 50°/27° 50°/27°
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Compaction – 3 static 3-wheeled; Large Tandem Finish
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Street Returns
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Hand Workable
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Quality Control
Std. Dev.
Tolerance
GMM 0.003 +/-.030
GMB 0.006 +/- .026
Voids 0.25 +/- 1.00
VMA 0.150 +/- 0.70
AC 0.16 +/- 0.03
Dust:AC 0.07 +/-1.20
4 Samples 1 set per night > 700 Tons per
night
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Finished Product
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Details
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The End – Thank You