A comparative flexural performance of an over-reinforced high strength concrete beam with normal strength beam

Abstract

This research work compared the flexural behavior of an over-reinforced High strength concrete beam with normal strength concrete beam. Totally 26 beams are casted in which 13beams for high strength concrete and remaining 13 are designed for normal strength concrete. Out of 13 one beam was kept as reference and remaining 12 beams are casted with varying volume fractions of steel and polypropylene fibers. All the beams are provided with more than the required percentage of steel which is slightly more than the balanced percentage. Providing a reinforcement in the tensile region itself behaves as an over-reinforced one. In general concrete fails by brittle manner hence forth in this study an attempt has been made to prove that even an over-reinforced beam offers resistance against the load applied and to ensure that the beam was casted by adding hybrid fibers along with proper confinement (stirrups with closed spacing) at the maximum moment section which enhances the flexural performance of the beam. As per ASTM C 78 all the beams were tested under third point loading and the deflections were measured using dial gauges at the respective places. Based on the experimental results it was proved that ductile behavior of the beams was improved just because of adding fibers in hybrid form along with stirrup confinement at the possible hinging region. Also, it was ensured that load carrying capacity of the beams was in turn improved not just in high strength concrete beam but also performs well with normal strength concrete beam.