Impact of Warm Mix Asphalt in Nebraska

Matt Beran, P.E.Assistant Flexible Pavements Engineer

Nebraska Department of Roads

Overview

What is Warm Mix Asphalt? (WMA) • Hot Mix Asphalt designs that are modified to be produced, placed and

compacted at 20-100°F less than typical Hot Mix Asphalt (HMA).

What is Warm Mix Asphalt?

Types of Additives

Warm Mix Asphalt Benefits

• Fuel Savings

Fuel Savings

• Fuel prices almost 3 times higher than last year• 10-20% potential fuel savings• Potential savings of $1 million each year

Warm Mix Asphalt Benefits

• Fuel Savings• Improved Workability

– Allows for longer haul distances– Extended paving season

Longer Haul Distances

Extended Paving Season

• December Paving (1 hour haul)

Warm Mix Asphalt Benefits

• Fuel Savings• Improved Workability

– Allows for longer haul distances– Extended paving season

• Reduced Emissions (Greenhouse Gases)– Will be key with continuing environmental

regulations

Reduced Emissions

Reduced Emissions

Reduced Emissions

Warm Mix Asphalt Benefits

• Fuel Savings• Improved Workability

– Allows for longer haul distances– Extended paving season

• Reduced Emissions (Greenhouse Gases)– Will be key with continuing environmental

regulations• Improved Work Environment

Improved Work Environment

Warm Mix Asphalt Benefits

• Fuel Savings• Improved Workability

– Allows for longer haul distances– Extended paving season

• Reduced Emissions (Greenhouse Gases)– Will be key with continuing environmental

regulations• Improved Work Environment • Possible Less Aging of Asphalt Binder• Improved Plant Performance

– Reduced wear on plant

Warm Mix Asphalt History

• 1997: First pavements constructed in Europe• 2004: First U.S. field trails in Florida and North

Carolina• 2006: Numerous field trails around U.S.• 2007: First field trail in Nebraska• 2008: Second field trial in Nebraska

– Over 200 WMA test sections across U.S.

Overview

Research Need

• Verify national findings• Testing WMA with local conditions

– Both laboratory and field testing– Evaluate if there is a superior type

• See if WMA can perform as good or better than HMA

UNL Research Project Plan

Warm Mix Project Locations

• STILL NEED TO GET CORRECT GRAPHIC

Warm Mix Project Locations

Highway 12: Monowi to Verdel • Sasobit able to give 80°drop in temperature• No problems when switching to Sasobit• No blue smoke with Sasobit• 15% fuel savings

Highway 14: Elgin to US-20

• 50°drop in temperature• More viscous feeling than HMA• No smoke with both Zeolite and Evothern• Minimal fuel savings

Visual Evaluation (‘09 & ‘11)

Research Needs

• Verify National Findings• Testing WMA with local conditions

– Both laboratory and field testing– Evaluate if there is a superior type

• See if WMA can perform as good or better than HMA

Overview

Benefits for Nebraska

• Accelerated timeline for implementation• Increased NDOR confidence in WMA• Increased contractor’s awareness• Met FHWA goals for WMA• WMA specification adopted January 2012• Will be utilizing on at least 4-6 projects this year

– Also on 2-3 Country Projects

Warm Mix Asphalt Benefits

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