FHWA-IDOTPaver Segregation Process Review

Preliminary Findings

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What is Paver Segregation?

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Paver Segregation Schematic

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Augers

Slat Conveyors

Edge of Pavement

Edge of Pavement

Gear Box

Segregation Cracks

Direction of Paving

B B

Paver Segregation Schematic – Section B-B

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B B

Core 1 Core 2

Slat Conveyor Edge

Slat Conveyor Edge

Gear Box

Opened in 1997IL-4 / Veterans Parkway Ext.

Crack Sealed in 1999

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Trepanier, J. (2018) History of Paver Induced Longitudinal Cracking in Illinois. Presented at the Illinois Department of Transportation Spring

2018 Hot-Mix Asphalt Technical Working Group Meeting, Springfield, IL.

Paver Segregation History in Illinois

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Background

• 1993 Crack Investigation of I-72 & I-155

– Full Depth HMA Pavements (1989-1991 Construction)

• I-72 - 35 miles

• I-155 - 29 miles

– Extensive Cracking on Both Routes

– Longitudinal Cracking Attributed to Paver Induced Segregation Especially on I-72

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Trepanier, J. (2018) History of Paver Induced Longitudinal Cracking in Illinois. Presented at the Illinois Department of Transportation Spring

2018 Hot-Mix Asphalt Technical Working Group Meeting, Springfield, IL.

Early 2000’s Paver Modifications

• Paver Segregation Kit Installation

• Paver Manufacturer Check Sheets

• Modified Standard Specifications (Art. 1102.03)

– Contractor submit cert. kit installed & operational

– Contractor/RE perform paver inspection prior to paving using manuf. checklist

– Completed checklist provided to RE

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Trepanier, J. (2018) History of Paver Induced Longitudinal Cracking in Illinois. Presented at the Illinois Department of Transportation Spring

2018 Hot-Mix Asphalt Technical Working Group Meeting, Springfield, IL.

No Paver Modifications

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Chain Curtain

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Chain Curtain

Chain Curtain Example

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Reverse Augers

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Pushing Material Under Gear Box

Sweeping Material Under Gear Box

Deflector Plates – Top View

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Augers

Slat Conveyors

Gear Box

Deflector Plates

Deflector Plates – Side View

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Deflector Plate

Deflector Plates

Deflector Plates – Side View

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Deflector Plates

Deflector Plate

Paver Segregation Recurrence in Illinois

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Paver Segregation ExampleI-72/US-36

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Google Maps

Paver Segregation ExampleI-74

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Google Maps

FHWA-IDOT Paver Segregation Process Review

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Process Review Members

• Dennis Bachman (FHWA)

• Craig Cassem (FHWA)

• Kevin Burke III (IAPA)

• Ryan Sheley (IDOT)

• Jim Trepanier (IDOT)

• Tom Zehr (IDOT)

• Brian Hill (IDOT)

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Process Review

• What is it?

– Evaluation of processes comprising an element of a program

• What are the goals?

– Evaluate Level of Compliance

– Recognize Best Practices

– Pinpoint Areas for Improvement

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National Highway Institute Training Course. Conducting Effective Program Reviews.

Scope and Methodology

• Review Existing Cases of Paver Segregation

• Inspect Pavers, MTD’s, and Paver Hopper Inserts at Contractors & Dealerships

• Collect Current Anti-Segregation Part Documents

• Evaluate Existing Specs & Special Provisions

• Identify Best Practices & Recommend Changes

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Scope and Methodology

• Review Existing Cases of Paver Segregation

• Inspect Pavers, MTD’s, and Paver Hopper Inserts at Contractors & Dealerships

• Collect Current Anti-Segregation Part Documents

• Evaluate Existing Specs & Special Provisions

• Identify Best Practices & Recommend Changes

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Core Testing

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Google Maps

Core Testing

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Google MapsSegregation Area Cores

Non-Segregation Area Cores

Core Locations

• District 2 - US-30

• District 3 - US-24

• District 4 - I-74

• District 5 - US-36

• District 6 - IL-29

• District 9 - US-51

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Average Core Air Voids

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Area Air Voids (%)

Segregation 6.7

Non-Segregation 5.1

Average Core Asphalt Contents

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Area AB Content (%)

Segregation 5.2

Non-Segregation 5.4

Paver Hopper Inserts

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Conical Pile in Paver Hopper Insert

Coarse Particles

Coarse Particles

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Coarse Particle Movement in Paver Hopper Insert

Paver Hopper Insert

Slat Conveyors

Coarse Particles

Coarse Particles

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Best Practices

• Winter Paver Evaluations/Meetings

– Equipment Suppliers/Contractors/Department

• Contractor Modifications

• Use of Thermal Measurement Technology

– Paver Mounted or Handheld Thermal Cameras

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Paver Mounted Thermal Camera Example

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VETA

Areas of Thermal Segregation

Areas for Future Improvement

• Communication– Equipment Suppliers/Contractors/Department

• Electronic Storage of Equipment Use– Daily Paving Records

• Paver Segregation Distress Identification

• Paver Hopper Insert and Paver Anti-Segregation Technology

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Thank You for Your Attention!

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