Housing and Building National Research Center HBRC Journal

KEYWORDSPartially prestressed;Fully prestressed;T-shaped;Steel fibers;Polypropylene fibers;Cracks-width;Flexural strength;Ductility;Energy absorptionAbstract This paper presents an experimental and analytical study on the behavior of post-ten-sioned concrete beams with variable discontinuous fibers’ content. Eleven half scale T-shapedpost-tensioned simple beams were cast and tested in four points bending under the effect of arepeated load using a displacement control system up to failure. The test parameters were the fibers’type (steel and polypropylene) and content, as well as the prestressing ratio (partially or fully). Keytest results showed considerable enhancement in the crack distribution, crack width and spacing,concrete tensile strength and flexural stiffness in all beams with steel fibrous concrete. The latteraspects were directly proportional to the steel fibers’ contents. On the other hand, beams containingpolypropylene fibers demonstrated a slight decrease in the flexural strength and a slight increase inflexural stiffness. In addition, the tensile steel strains decreased in all fibrous concrete beams, withlowest values in steel fibrous concrete specimens when compared to those of the polypropylenefibers. Furthermore, fibrous concrete beams also demonstrated enhanced ductility and energyabsorption, which reached the highest values for steel fibrous concrete specimens. Generally, itcan be concluded that steel fibers proved to have higher structural efficiency than polypropylenefibers, when used in the tested specimens.a 2013 Housing and Building National Research Center. Production and hosting by Elsevier B.V.All rights reserved.