08 jay behnke

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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Fractionating FRAP Plant

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