CRACK-ARREST TECHNIQUES IN REINFORCED CONCRETE STRUCTURAL ELEMENTS; REPORT 1, LABORATORY TESTS

In this study, tests were conducted to develop improved methods of arresting or preventing undesired flexural cracking within the tensile zones of conventionally reinforced concrete beams. Specimens representing several potential crack-arrest techniques including (a) fiber-reinforced concrete, (b) concrete with wire mesh, and (c) epoxy-resin concrete were tested under either short- or long-term static loading. The principal conclusions of the investigation are as follows: (a) randomly mixed steel fibers incorporated in concrete can increase the precracking load over that of conventionally reinforced concrete; (b) 0.5-in.-long fibers will produce better results in certain mixtures than will 1-in.-long fibers; (c) steel fibers do not significantly increase the flexural capacity of conventionally reinforced beams; (d) properly constructed and positioned wire cages can increase the precracking loads of flexural members; (e) epoxy-resin concrete layers provided within the tensile zones of small conventionally reinforced composite beams can increase precracking loads by as much as 300 percent over those of conventionally reinforced concrete beams; (f) the size of cross section, length of member, etc., may influence the initial cracking load and resulting crack pattern as much as the size and spacing of the reinforcement; (g) although sustained loading does not appear to affect the ultimate loads of members using any of the tentatively recommended crack-arrest techniques, it does significantly affect crack patterns; (h) neglecting cost, placing steel fibers throughout the entire cross section appears to be the best technique, but the desired results can also be obtained using epoxy-resin concrete or concrete with wire mesh; and (i) design according to the tentative recommendations outlined herein can be expected to have maximum crack widths smaller than those of conventionally reinforced members by factors of 1.4 to 2.5; however, it is emphasized that these designs are based on a limited number of tests and could be subject to change as additional test results become available.

  • Corporate Authors:

    U.S. Army Waterways Experiment Station

    3909 Halls Ferry Road
    Vicksburg, MS  USA  39180-6199
  • Authors:
    • Cox, F B
  • Publication Date: 1974-11

Media Info

  • Pagination: 161 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00080811
  • Record Type: Publication
  • Report/Paper Numbers: C74-7 Tech. Rpt.
  • Files: TRIS
  • Created Date: Sep 27 1978 12:00AM