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    Crack Control in Concrete Bridges: Presented by M. Myint Lwin, Director FHWA Office of Bridge Technology

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    EmilioLimberArredondoOyola
    The document summarizes a workshop on concrete cracking that took place in August 2005 at Northwestern University. It discusses causes of cracking such as materials, design, and construction practices. It also covers constituent materials of concrete, structural design practices, ultra-high performance concrete, and construction practices that can lead to cracking. The document concludes by discussing challenges in eliminating cracking, the goal of crack-free concrete, and the need for collaboration between different fields to advance technologies and research towards this goal.

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    Crack Control in Concrete Bridges: Presented by M. Myint Lwin, Director FHWA Office of Bridge Technology

    Uploaded by

    EmilioLimberArredondoOyola
    28 views22 pages
    The document summarizes a workshop on concrete cracking that took place in August 2005 at Northwestern University. It discusses causes of cracking such as materials, design, and construction practices. It also covers constituent materials of concrete, structural design practices, ultra-high performance concrete, and construction practices that can lead to cracking. The document concludes by discussing challenges in eliminating cracking, the goal of crack-free concrete, and the need for collaboration between different fields to advance technologies and research towards this goal.

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    CCW_I_B.pdf

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    The document summarizes a workshop on concrete cracking that took place in August 2005 at Northwestern University. It discusses causes of cracking such as materials, design, and construction practices. It also covers constituent materials of concrete, structural design practices, ultra-high performance concrete, and construction practices that can lead to cracking. The document concludes by discussing challenges in eliminating cracking, the goal of crack-free concrete, and the need for collaboration between different fields to advance technologies and research towards this goal.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    28 views22 pages

    Crack Control in Concrete Bridges: Presented by M. Myint Lwin, Director FHWA Office of Bridge Technology

    Uploaded by

    EmilioLimberArredondoOyola
    The document summarizes a workshop on concrete cracking that took place in August 2005 at Northwestern University. It discusses causes of cracking such as materials, design, and construction practices. It also covers constituent materials of concrete, structural design practices, ultra-high performance concrete, and construction practices that can lead to cracking. The document concludes by discussing challenges in eliminating cracking, the goal of crack-free concrete, and the need for collaboration between different fields to advance technologies and research towards this goal.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 22

    Concrete Cracking Workshop

    August 18 & 19, 2005


    Northwestern University, Evanston, IL

    Crack Control in Concrete Bridges

    Presented By
    M. Myint Lwin, Director
    FHWA Office of Bridge Technology
    Crack-free Structures
    Concrete Cracking
    Concrete Repair
    What Cause Cracking

    ) Materials?

    ) Structural/Architectural Design?

    ) Construction Practices?
    Constituent Materials of Concrete

    ) Cement
    – Fly Ash
    – Silica Fume
    – Slag
    ) Fineand Coarse Aggregates
    ) Admixtures
    ) Corrosion Inhibitors
    Contituent Materials of Concrete
    (Contd)

    ) Water-Cementitious Materials Ratios


    ) Permeability
    ) Compressive Strength
    ) Reinforcement
    Structural Design Practices

    ) Stressintensity
    ) Member size
    ) Reinforcement details
    ) Cover to reinforcement
    Ultra High-Performance Concrete
    (UHPC)
    ) Cost = 10 times more!

    ) Challenge = Optimize Section; Minimize Structure


    Construction Practices

    ) Concrete Temperature
    ) Weather Conditions
    ) Concrete Placement
    – Consolidation
    ) Curing
    Crack Widths

    Reinforced Concrete Prestressed Concrete


    English (in.) Metric (mm) English (in.) Metric (mm)

    Hairline < 1/16 < 1.6 <0.004 < 0.1


    < 0.0625
    1/16 to 1/8 1.6 to 3.2 0.004 to 0.009 0.1 to 0.23
    Narrow
    0.0625 – 0.125
    1/8 to 3/16 3.2 to 4.8 0.010 to 0.030 0.25 to 0.76
    Medium
    0.125 – 0.1875
    3/16 > 4.8 > 0.030 > 0.76
    Wide
    > 0.1875
    Challenges

    ) Eliminate Time-Dependent Factors


    ) Eliminate Corrosion
    ) Produce Self-Healing Concrete
    ) Improve tensile strength significantly.
    ) Develop effective crack sealing materials
    ) Develop crack control methods
    Closing Remark
    ) Ourlofty goal = crack-free concrete.
    ) Working together
    – Materials scientists/engineers
    – Structural engineers
    – Admixture suppliers
    – Contractors
    ) Integratingknowledge and skills,
    research, technologies and innovations
    Closing Remark

    Let the ideas from this workshop:


    Plant the seeds
    For research that
    Lights the way
    To Crack Free Concrete!!!
    Research Funds
    ) Research, Deployment and Education
    – HPC = $4.1M/Year
    – LTBP = $7.75M/Year
    – IBRD = $13.1M/Year
    – UHPC Demo = $0.625M/Year
    ) Exploratory Advanced Research = $14.0M/Year
    ) Highway for Life
    – $15.0M/Year
    – For Market-Ready Technology

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