WMA TWG December 2007 1

NCAT WMA Research 2007

Andrea Kvasnak

WMA TWG December 2007 2

WMA Field Projects

• Chattanooga, TN

• Silverthorne, CO

• Birmingham, AL

• Nashville, TN

• Rock Hill, SC

WMA TWG December 2007 3

Chattanooga

• Two site visits

• Both using Astec Green System

• Visit 1:– Parking lots at Astec Plant

• Visit 2:– North Terrace Road

WMA TWG December 2007 4

Chattanooga Site 1

• Foamed Asphalt– Moisture added was 0.1% by wt of total mix

• Compaction Temperatures– 245°F for Virgin– 265°F for RAP

• Haul, place and compact using normal procedures

WMA TWG December 2007 5

Placement of Foamed Asphalt at Astec Plant

• 30% RAP base placed first

• Some issues with poor base support

• Material was workable

• Reduced odor

WMA TWG December 2007 6

Placement of Virgin Mix

• Outside bay doors• Target compaction

temperature of 245°F

• Compaction was same

• Some issues with handwork

WMA TWG December 2007 7

Placement of 30% RAP Surface

• Atop 30% base course

• Compacted at lower temperature than target

• No issues with compacting

WMA TWG December 2007 8

Chattanooga Site 1: Laboratory Testing

• Mobile lab compacted specimens at location• Moisture Susceptibility

– 30% RAP base and virgin surface > 0.9 TSR– 30% RAP surface ~ 0.58 TSR

• Asphalt Pavement Analyzer– RAP mixes performed better than virgin

• Hamburg Wheel Tracking Device– Stripping inflection points < 10,000– RAP mixes passed, virgin did not

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Chattanooga TN Site 2

• Astec Double Barrel Green

• 2” overlay

• 50% RAP

• Place at 270°F

WMA TWG December 2007 10

Chattanooga Site 2:Laboratory Testing

• Moisture Susceptibility– Average TSR of 0.8

• Asphalt Pavement Analyzer– Average rut depths < 4 mm

• Hamburg Wheel Tracking Device– Ruts < 5 mm– Stripping inflection < 10,000

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Silverthorne, CO

• Three WMA technologies– Advera WMA– Sasobit– Evotherm DAT

• Night time paving

• Mountain terrain with heavy truck traffic

WMA TWG December 2007 12

Birmingham, AL

• Evotherm DAT

• State Rd 79

• Night time paving

• WMA and HMA produced and placed– WMA: 15% RAP– HMA: 10% RAP and 5% shingles– Originally considered RAS for both

WMA TWG December 2007 13

Birmingham, AL cont.

• PG 67-22 binder

• HMA and WMA placed in the same lane

• About 2050 tons of each mix

• 1.5 nights of paving for each mix– Test strips (500 tons) and full paving stretch

WMA TWG December 2007 14

Birmingham, AL:Laboratory Testing

• Moisture susceptibility– 3 out of 4 nights passed (2nd WMA 0.7)

• APA– APA: WMA > 5 mm, HMA > 3 mm

• IDT creep compliance– Not completed

• Dynamic modulus– Not completed

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Shingles

• ALDOT and others interested in trying shingles

• Concern: Temperature not high enough to get shingle binder activated

• Looking into doing some at the NCAT test track– Specimens will be compacted on site

WMA TWG December 2007 16

Nashville, TN

• SR 46 in Nashville • 4 WMA Technologies and 2 controls

– Astec Green System – Advera WMA – Evotherm DAT – Sasobit

• 3 Plants– 2 different aggregate sources– Furthest haul 45-60 minutes

WMA TWG December 2007 17

Nashville, TN cont

• PG 70-22

• Marshall mix

WMA TWG December 2007 18

Nashville, TN Field Information

• Astec Green System– 775 tons– Compaction: 230°F– Density: 91.6%

• Advera WMA– 1150 tons– Compaction: 235°F– Density: 92.7%

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Nashville, TNField Information Cont.

• Evotherm DAT– 750 tons– Compaction: 230°F-250°F– Density: 91%

• Sasobit– 705 tons– Compaction: 245°F– Density: 91.7%

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Nashville, TN:Laboratory Testing

• Moisture Susceptibility– All failed except Astec Green (0.83)

• APA – Average rut depths for all less than 8mm

• Hamburg– Not completed

• IDT Creep Compliance– Not completed

• Dynamic Modulus– Not completed

WMA TWG December 2007 21

Rock Hill, SC

• 4 mixes– Fractionated RAP– 30% RAP Intermediate and Surface– 50% RAP Intermediate and Surface

• PG 64-22

• Testing has not been initiated

WMA TWG December 2007 22

Questions?