WMAWMAKenneth Ray Hobson, P.E.

Bituminous Engineer

OverviewOverview

• State Perspective

• Qualified Sources

• Specifications

• Lab Sampling & Testing

• Review

• Acronyms

State PerspectiveState Perspective

• Improve Quality– Air Emissions– Density– Longevity

• Decrease Cost– Burner Fuel Savings

• Implementation

Qualified SourcesQualified Sources

• Approved Technologies:http://v.gd/nBTKiI

–Foaming–Chemical–Organic

Qualified SourcesQualified Sources

SpecificationsSpecifications

• WMA Special Provisions– 411-13 http://v.gd/ljMfSQ

• Behind Paver Min. 215°F [102°C]• HMA - 250°F [121°C]

– 708-22 http://v.gd/ohpb4Y• Reheat from 100°F [38°C]• Heat 4 hours at 300°F [149°C]

– AASHTO T 283 Moisture Sensitivity– OHD L-55 Hamburg Rut Test

SpecificationsSpecifications

• Roadway Compaction Temperature Trends– WMA Chemical 230°F– WMA Foaming 260°F– HMA w/ PG 64-22: 290°F– HMA w/ PG 70-28: 305°F– HMA w/ PG 76-28: 305°F

SpecificationsSpecifications

• Designs http://v.gd/eWi4Vg

SpecificationsSpecifications

Lab Sampling & TestingLab Sampling & Testing

• Similar to HMA except for Reheat

• WMA Chemical & Organic Technologies– Lab Compaction Temperatures Vary

Automatic Marshall Hammers

Superpave Gyratory Compactor (SGC)

ReviewReview

• State Perspective– Improve Quality– Decrease Cost– Implementation• Qualified Sources - http://v.gd/nBTKiI

ReviewReview

• Specifications– 411-13 http://v.gd/ljMfSQ– 708-22 http://v.gd/ohpb4Y

• Lab Sampling & Testing– Similar to HMA except for Reheat– WMA Chemical & Organic Technologies

• Lab Compaction Temperatures Vary

AcronymsAcronyms

• Ndes – Number of SGC Gyrations at JMF Binder

• Nini – Number of SGC Gyrations backcalculated from Ndes Specimens– Density Similar to That Behind Paver

• Nmax – Number of SGC Gyrations at End of Pavement Life (mix design only)

AcronymsAcronyms

• WMA – Warm-Mix Asphalt

• HMA – Hot-Mix Asphalt

• RAP – Recycled Asphalt Pavement

• RAS – Recycled Asphalt Shingles

• ODOT – Oklahoma Department of Transportation

• ASA – Anti-Strip Additive