John A. D’AngeloUS Federal Highway Administration

CUPGA 2008Saskatoon, Saskatchewan

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How Many WMA Technologies are Available in the U.S.?

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Currently 12 Technologies Actively Marketed and Available in the U.S.

How Many WMA Technologies are Available in the U.S.?

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Warm Mix Trials and DemonstrationsWarm Mix Trials and Demonstrations

Trial completed

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There is a tremendous growth in interest in Warm Mix in the US

WHY?Fuel costs are up.

Bitumen cost have spiked.

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Change in Producer Prices for Construction Segments

Source: BLS (CPI, PPI)

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Change in Producer Price Indexes (PPI) for Highway Inputs

Source: BLS (CPI, PPI)

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Change in Producer Price Indexes (PPI) for Asphalt

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Economic Drivers for Using RAP

Growth in recycling occurs when it is economical to do so.

Warm Mix Technology can improve RAP workability.

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Fractionated RAP

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A review of some projects and what we have learned

Hall Street St. Louis

I70 Colorado

Entrance to Yellowstone

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Hall Street, St. Louis, MO

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St. Louis Paving ScheduleControl (12.5mm PG 70-22) – 5/17/06

Sasobit – 5/18/06

Sasobit – 5/19/06

Evotherm – 5/22/06

Evotherm – 5/23/06

Aspha-Min – 5/25/06

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Interstate 70, Dillon, CO

Dillon

70 miles West of Denver, CO

Elevation 8,800 – 11,100

Feet

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Mix Type

FieldProperty

Control 7-24-07AdveraWMA

Control 7-26-07Sasobit

Control 8-13-07Evotherm

Low AirTemp. (°F)

54 54 50 50 36 36

DeliveryTemp. (°F)

* 260 * 235 * 243

At ScreedTemp. (°F)

* 243 * 230 * 235

MatDensity

(% Rice)

93.8 93.3 95.7(single

data point)

93.2 93.7 94.7

* Minimum delivery temp for control HMA was 280 °F

Chart is Courtesy of CODOT

Interstate 70, Dillon, CO

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Construction Highlights Mix Type

Property

Control 7-24-07AdveraWMA

Control 7-26-07Sasobit

Control 8-13-07Evotherm

Results are from the CDOT QA lab – QC results were comparable FHWA’s mix flow number, dynamic modulus and binder test data are pending.

AC (%) 6.23 6.38 6.41 6.32 6.04 6.38

Voids (%) 3.1 1.8 3.0 2.4 3.6 2.2

VMA (%) 16.5 15.7 16.5 15.9 16.3 15.8

MatDensity

(% Rice)

~94 ~94 ~94 ~94 ~94 ~94

TSR (%) 100 83 *97 111 94 80

Stability 36 34 35 36 35 34

Hamburg(mm rut)

9.46 9.79 17.31 10.49 10.10 14.86

* Average of other control mix tested on the job.

Regardless of Hamburg Rut Depth, Moisture damage more prevalent in the WMA samples than the control samples – see following pictures

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ConclusionsWMA decreased voids in lab compaction

WMA field compaction comparable at lower temps

Hamburg moisture damage visibly more in WMA

Early WMA performance equal to HMA on the jobNo rutting, no early distresses

Confident that WMA facilitates cold temp. placement

Will use more WMA in this corridor if performance is comparable to HMA

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East Entrance, Yellowstone, WY

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Mixture Locations

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Control - 3.82 mm and 4.00 mm

Advera - 3.80 mm and 3.25 mm

Sasobit - 3.28 mm and 2.60 mm

*All the testing was performed at 40°C wet and reported at 20,000 passes.

Yellowstone Hamburg

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FLH-What Have We Learned

Field density achieved in all cases

Saved ≈ 20% in fuel at the plant

Temperature at plant hard to regulate

Mix handled similarly

Workers noted no handling difficulties

No smoke

Additives don’t seem to affect mix design

Sasobit stiffens binder

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Objective

Evaluate the effects of three Warm Mix process namely Sasobit, Aspha-Min and Evotherm on M320-Table 2 Performance Grade

To Compare the Performance Grades of Warm Mix processes with the base asphalt used in preparing warm mix asphalts

Binder Characterization

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Hall Street, St. Louis, MOM320 ContinuousPerformance Grade

M320, Table 2Performance Grade

Additive Rate, by wt of binder

Base 70.9 – 24.870.9 – 24.8 70 - 2270 - 22

w/ Sasobit 76.5 – 22.876.5 – 22.8 76 - 2276 - 22 1.5%

w/ Aspha-Min 72.4 – 24.672.4 – 24.6 70 - 2270 - 22 5.26%

Evotherm (recovered per ASTM D 6934)

66.6 – 26.766.6 – 26.7 64 - 2264 - 22

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FindingsSasobit – increase of one high temp. PG grade Aspha-Min - no effect on PG gradeEvotherm

recovered at BASF, no effect on the PG graderecovered from the stored emulsion, reduced by one high temp. PG grade

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Cost Example

Fuel usage2.12 gallons/ton of mix -- Control

1.62 gallons/ton of mix -- Advera

1.80 gallons/ton of mix -- Sasobit

• 20 to 25 % fuel savings ≈ $1/ton of mix

• Cost for Advera ≈ $3.30/ton of mix

• Cost for Sasobit ≈ $2.30/ton of mix• Cost occurred in August 2007

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WMA Technical Working Group (TWG)

Formed in 2005Formed in 2005Purpose:Purpose:

Promote Technology TransferPromote Technology TransferFacilitate Product Approval MethodsFacilitate Product Approval MethodsEncourage ResearchEncourage ResearchDevelop Quality and Environmental Testing Develop Quality and Environmental Testing ProtocolsProtocolsProvide Guidelines for Mix Design and Provide Guidelines for Mix Design and ConstructionConstructionIdentify Other Benefits of WMAIdentify Other Benefits of WMA

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www.warmmixasphalt.comMaterial Testing FrameworkEmission Testing FrameworkWMA Best Practices DocumentResearch Needs Identified

Developed three (3) research statementsSubmitted through AASHTO to NCHRP• All projects highly ranked by SCOR• Total $1.4 million

WMA TWG Accomplishments

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NCHRP Research ProjectsNCHRP Research Projects

NCHRP Project 09-43NCHRP Project 09-43““Mix Design Practices for Warm Mix Asphalt”Mix Design Practices for Warm Mix Asphalt”

$500,000.$500,000.0000

Advanced Asphalt Technologies, LLCAdvanced Asphalt Technologies, LLC

NCHRP Project 09-47NCHRP Project 09-47““Engineering Properties, Emissions, and Field Engineering Properties, Emissions, and Field Performance”Performance”$900,000.$900,000.0000

Principal Investigator: Asphalt InstitutePrincipal Investigator: Asphalt Institute

3434WMA SCAN 2007WMA SCAN 2007

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Warm Mix Asphalt: Best PracticesWarm Mix Asphalt: Best PracticesQuality Improvement Quality Improvement Series (QIP) 125Series (QIP) 125

Stockpile Moisture ManagementStockpile Moisture Management

Burner Adjustments and Burner Adjustments and EfficiencyEfficiency

Aggregate Drying and Baghouse Aggregate Drying and Baghouse TemperaturesTemperatures

Drum Slope and FlightingDrum Slope and Flighting

Combustion AirCombustion Air

RAP usageRAP usage

Placement ChangesPlacement Changes3535

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WMA US Implementation

To date trial projects have been place in over 50% of the US states.

The oldest projects are now 3 to 4 years old with no indication of poor performance.

Over 500,000 tons of WMA have been placed.

Two states want to use WMA as a alternative to Hot Mix now.

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WMA US Implementation

Major concernsPotential for moisture damage.

Long term durability.

Mix design changes.

Thank You

Questions