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OPTIMIZING ASPHALTMIX DESIGNS

MIX DEVELOPMENT, AGENCY APPROVAL, MATERIALMANAGEMENT, FIELD ADJUSTMENTS

Rocky Mountain Asphalt Conference and Equipment ShowFebruary 25, 2010

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DEFINE OPTIMIZING

Whos Perspective

Producer

Paving Contractor

General Contractor

Owner

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MIX DEVELOPMENT

Project Specifications

Asphalt Binder Selection

Recycled Materials Recycled Asphalt Pavement (RAP)

Recycled Asphalt Shingles (RAS)

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MIX DEVELOPMENT

Aggregate Source / Characteristics

Aggregate Production Stationary or Mobile Plant

Hot Mix Asphalt Production Stationary or Mobile Plant

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Design Considerations

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Design Considerations

Quality

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Design Considerations

Availability

Quality

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Design Considerations

Availability

Quality

Balance

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Design Considerations

Availability

Quality

Balance

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Design Considerations

Availability

Quality

Economics

Balance

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AGENCY APPROVAL Conformance to contract requirements

Selection of JMF Durability considerations

Appropriate binder content for location

Strength (stability) considerations

Avoid fat side of VMA

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MATERIAL MANAGEMENT

Aggregate Quality Control Tests

Gradation, Specific Gravity, Angularity

Frequency

Stockpiling / Handling

Recycled Product(s) Quality Control Tests

Asphalt Binder Content, Gradation, Binder Grade

Frequency

Stockpiling / Handling

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MATERIAL MANAGEMENT

Asphalt Binder Tests

Binder Grading AASHTO M320, PG 64-28 add Toughness andTenacity

Frequency

Storage and Handling

Hot Mix Asphalt Production Control Tests

Gradation, Asphalt Binder Content, Theoretical MaximumSpecific Gravity, % Voids, Calculate % Voids in MineralAggregate

Frequency

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FIELD ADJUSTMENTS

Typical Production Results versus Laboratory DesignData for the Same Gradation and Asphalt Bindercontent:

Increased Bulk Specific Gravity of Mixture

Lower % Voids in Mix

Lower Calculated % VMA

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FIELD ADJUSTMENTS

Adjusting to Meet Volumetric Targets DuringProduction

Acceptance Criteria Gradation Acceptance or VoidsAcceptance?

Analyze Trends

Binder content in comparison with Rice Binder content in comparison with air voids

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FIELD ADJUSTMENTS

Gradation Acceptance / Voids Acceptance

Reduce Asphalt Binder Content if %VMA is OK

Change Gradation For a mix above the Maximum Density Line target the

Fine Side of the Targets without increasing -#200

Reject Baghouse Fines if Necessary to Reduce -#200

Request Target Changes to Asphalt Binder Content andGradation / Request Target Change to Asphalt BinderContent

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