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  • 1.  Suggestions for Hairline Crack?

    Posted 10-09-2018 10:48 PM
    Edited by Tirza Austin 10-09-2018 11:37 PM
    Hi all,

    Any suggestion on how to repair concrete hair or hairline crack?

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    Sayed Maqsood S.M.ASCE

    Oakland CA
    (510)395-4361
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  • 2.  RE: Suggestions for Hairline Crack?

    Posted 10-10-2018 10:02 AM
    If indoors, don't worry about them, except for pure appearance, in which case apply a coating system appropriate for the location.

    Outdoors, same answer, but different products. Obviously, all coatings should have some degree of lifetime elastomeric properties for the full range of exposure.

    If a hairline crack evolves to be a non-hairline crack over time and is revealed through the coating, go to Plan B.

    Next time avoid the crack hassle. Use a non-shrink mix design (e. g., a Type K cement or similar via an admixture and non-shrink aggregates), even if your concrete element may be a column or prestressed.  (If you are wondering about the column, do a stress/elastic deformation allocation analysis between the rebar and the concrete, then throw in what drying shrinkage stresses may contribute to the steel stress/deformation over the lifetime.)

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    Robert Bullard P.E., M.ASCE
    President
    Ahimsa Technic Inc
    Ponce Inlet FL
    (386)256-3050
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  • 3.  RE: Suggestions for Hairline Crack?
    Best Answer

    Posted 10-10-2018 10:03 AM
    Edited by Sayed Maqsood 10-10-2018 04:18 PM
    ​Sayed -

    The Florida Department of Transportation has a comprehensive procedure for classifying cracks in concrete and specifying appropriate repair methods for different situations.  This can be found in Section 400-21, Disposition of Cracked Concrete, in the FDOT Standard Specifications for Road and Bridge Construction (see link below).  I suspect that Caltrans and other agencies would have similar specifications.

    http://www.fdot.gov/programmanagement/Implemented/SpecBooks/January2019/Files/119eBook.pdf
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    View this on Fdot >


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    Robert Smith P.E., M.ASCE
    Senior Project Engineer
    Stantec
    West Palm Beach FL
    (561)209-7460
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  • 4.  RE: Suggestions for Hairline Crack?

    Posted 10-10-2018 12:19 PM
    Edited by Tirza Austin 10-10-2018 12:18 PM
      |   view attached
    Concrete International had a brief discussion of acceptable cracking (although not how to repair them) in the Concrete Q&A section (attached) of the March 2018 issue based on guidance from ACI 224-01.

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    Robert Yates P.E., M.ASCE
    Applications Engineer
    FiberForce by ABC Polymer Industries, LLC
    Roseville, CA

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    Attachment(s)



  • 5.  RE: Suggestions for Hairline Crack?

    Posted 10-11-2018 08:04 AM
    Edited by Tirza Austin 10-11-2018 08:04 AM
    Here is an article that was emailed to me today about this very issue. Hope it helps!

    Hairline Cracks Cured with PENETRON's Crystalline Technology
    PRWeb remove preview
    Hairline Cracks Cured with PENETRON's Crystalline Technology
    EAST SETAUKET, N.Y. (PRWEB) October 09, 2018 -- When the new cooling tower basin at the Praxair industrial gas production facility in Louisiana started to leak water through hairline shrinkage cracks during tests, PENETRON ADMIX - with its crystalline technology - turned out to be the optimal solution to an inherent issue with new concrete.
    View this on PRWeb >



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    Gregory Nault P.E., S.E., M.ASCE
    Project Manager
    LafargeHolcim
    Chicago IL
    (773)372-1027
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  • 6.  RE: Suggestions for Hairline Crack?

    Posted 10-11-2018 12:40 PM
    Edited by Tirza Austin 10-11-2018 12:40 PM
    Thanks for sharing, it's an impressive article. 

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    Sayed Maqsood S.M.ASCE

    Oakland CA
    (510)395-4361
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  • 7.  RE: Suggestions for Hairline Crack?

    Posted 10-12-2018 11:53 AM
    Edited by Tirza Austin 10-12-2018 11:52 AM
    ​The following references discuss causes, evaluation, prevention, and repair of cracks in concrete and may be a good source of information for what you are looking for:

    • Portland Cement Association:
      • PCA R&D Serial No. 2155 (ISBN No. 0-89312-212-Z)
    • American Concrete Institute:
      • ACI 201.1R
      • ACI 224R
      • ACI RAP-1


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    Gustavo Escorcia P.E., Ing., M.ASCE
    Structural Engineer
    STV / Ralph Whitehead and Associates
    North Chesterfield VA
    (804)794-1185
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