Drying shrinkage, when restrained, contributes to nearly all the cracking observed in concrete members before loading. A free shrinkage test cannot therefore give the true potential of fiber reinforcement to resist restrained shrinkage stresses and to control shrinkage cracking. A ring type of restrained shrinkage test is reported to demonstrate the ability of short, discrete fibers such as polypropylene, glass, and steel to control cracking and resist tensile stresses arising from restrained shrinkage. Three series of free and restrained shrinkage tests are reported with different matrices, types of fibers, and fiber contents. It is shown that the presence of fibers exercises a clear but small restraint to free shrinkage, and reduces drying shrinkage by up to 20 percent. When shrinkage is restrained, fiber reinforcement delays the formation of the first crack, prevents sudden failure observed with unreinforced matrices, enables the composite to suffer multiple cracking without failure, and reduces crack widths substantially. The fiber reinforced specimens were able to resist 50 to 100 percent more tensile stresses, and continued to resist the shrinkage stresses even after 8 to 12 months. /Author/

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  • Corporate Authors:

    American Concrete Institute

    P.O. Box 19150, Redford Station, 22400 Seven Mile Road
    Detroit, MI  United States  48219
  • Authors:
    • Swamy, R N
    • Stavrides, H
  • Publication Date: 1979-3

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Filing Info

  • Accession Number: 00193572
  • Record Type: Publication
  • Report/Paper Numbers: Tech Paper
  • Files: TRIS
  • Created Date: May 26 1979 12:00AM