KUKU

KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Engineering
    • Infrastructure Research Institute Scholarly Works
    • View Item
    •   KU ScholarWorks
    • Engineering
    • Infrastructure Research Institute Scholarly Works
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Bond of Epoxy-Coated Reinforcement: Cover, Casting Position, Slump, and Consolidation

    Thumbnail
    View/Open
    Darwin_1994.pdf (1.903Mb)
    Issue Date
    1994
    Author
    Hadje-Ghaffari, Hossain
    Choi, Oan Chul
    Darwin, David
    McCabe, Steven L.
    Publisher
    American Concrete Institute
    Type
    Article
    Article Version
    Scholarly/refereed, publisher version
    Published Version
    https://iri.ku.edu/reports
    Metadata
    Show full item record
    Abstract
    The effects of concrete cover, casting position, concrete slump, and degree of consolidation on the reduction in bond strength between reinforcing bars and concrete caused by epoxy coating are described. Tests include beam-end specimens containing No. 5, No. 6, No. 8 and No. 11 (16, 19, 25, and 46 mm) bars. Bottom-cast and top-cast bars with 1, 2, or 3 bar diameters of cover are evaluated. Concrete slump ranges from 2 1/4 to 8 in. (55 to 205 mm). some specimens containing high slump concrete are not vibrated. The results of the study are used to develop improved development length modification facts for epoxy-coated bars. Epoxy coatings significantly reduce bond strength. However, the extent of the reduction is less than used to select the development length modification factors in the 1989 ACI Building Code and the 1989 AASHTO Bridge Specifications for bars with cover < 3 bar diameters (db) or a clear spacing < 6 db. The development length modification factor can be reduced from 1.5 to 1.35 for these bars. The relative bond strength of epoxy-coated reinforcement increases as cover increases. As a result, the development length modification factor of 1.2 in ACI 318-89 is realistic for epoxy-coated bars with a cover > 3 db and a clear space > 5 db (ACI) or a center-to-center spacing > 6 in. (AASHTO). However, the modification factor of 1.15 in the 1989 AASHTO Bridge Specifications is slightly unconservative for these bars and should be modified. The ratio of the bond strength of bottom-cast bars to the bond strength of top-cast bars, B/T, is about the same for coated and uncoated bars and decreases slightly for coated bars as slump increases. As a result, the upper limit on the product of the epoxy-coating factor and the top-bar factor can be reduced from 1.7 to 1.5. A lack of vibration has a negative effect on the bond strength of both coated and uncoated reinforcement in high slump concrete. This is the third in a series of papers describing research at the University of Kansas on epoxy-coated reinforcement. The research is aimed at gaining a better understanding of the bond of epoxy-coated reinforcement to concrete and developing design procedures that accurately reflect the changes in bond strength caused by epoxy coating.
    URI
    http://hdl.handle.net/1808/23418
    Collections
    • Infrastructure Research Institute Scholarly Works [332]
    Citation
    Hadje-Ghaffari, H., Choi, O. C., and McCabe, S. L., "Bond of Epoxy-Coated Reinforcement: Cover, Casting Position, Slump, and Consolidation," ACI Structural Journal Vol. 83, No. 7, January-February 1994, pp. 59-68.

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    Login

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    The University of Kansas
      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps