EFFECT OF BINDER COURSE ON OVERLAY PERFORMANCE

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College of Engineering Research Symposium,
2006 The Pennsylvania State University
EFFECT OF BINDER COURSE ON OVERLAY PERFORMANCE A
CASE STUDY ON I 79 (Project funded by
Pennsylvania Department of Transportation,
District 10)
Tanmay Kumar Graduate Student and Dr. Ghassan
Chehab Assistant Professor Department of Civil
and Environmental Engineering
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In this presentation

• Introduction
• Pavements
• Pavement distresses
• I 79 in Butler county, PA
• Existing pavement
• Rehabilitation techniques
• Experimental evaluation
• Continuing work
• Questions

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What is a Pavement?

• A multi layer system that distributes the
  vehicular loads over a larger area

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Pavement Distresses

• Due to loading and / or structure
• Rutting or Permanent deformation
• Fatigue cracking (Bottom-up cracking)
• Edge-of-wheel cracking (Top-down cracking)

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Interstate 79 in Butler County

• AC over PCC pavement
• Wheel-path (top-down) cracking

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Rehabilitation Techniques

• Typical Place 1.5 in. AC overlay over existing
  AC
• Experimental Place 2 in. binder layer between
  existing AC and new 1.5 in. AC

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Objectives and Methodology

• Objective
• Evaluate effectiveness of binder layer in
  preventing or controlling pavement distresses
• Methodology
• Full scale field testing
• Accelerated laboratory testing
• Analytical tools
• Finite Element Analysis
• M-E Design Guide
• Linear Elastic Multi-layer Analysis

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Accelerated Pavement TestingModel Mobile Load
Simulator at 1/3rd Scale (MMLS3)
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MMLS3
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MMLS3
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But I thought thicker members were always
stronger
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MMLS3

• Why does inclusion of binder layer reduce rutting
  resistance?
• Higher edge-of-wheel shear stresses
• Edge-of-wheel top-down cracking
• Material deficiencies

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Finite Element Analysis
No binder layer
4 in. binder layer
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Performance Prediction

• Models provided in the M-E Design Guide
• Increase in binder layer thickness
• Marginal increases rutting
• Negligible effect on Fatigue cracking
• Top-down cracking highly sensitive

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Continuing Work

• Additional tests using MMLS3 at moderate
  temperatures to simulate wheel-edge cracking
  without rutting
• Advanced 3D FE models incorporating
  viscoplasticity to simulate growth of rutting
• Evaluate alternate mix designs for binder layer
• Relate MMLS3 axles to actual traffic
• Indirect tension (IDT) tests to evaluate thermal
  cracking potential of both mixes

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Questions