BEHAVIOUR OF POLYPROPYLENE FIBRE REINFORCED FLY ASH CONCRETE DEEP BEAMS IN FLEXURE AND SHEAR

The behaviour of deep beams is different from that of shallow beams in which the bending stress distribution is linear across the depth and the shear failure is ductile. This paper addresses the flexure and shear behaviour of polypropylene fibre reinforced fly ash concrete (PFRFAC) deep beams. The shear span to depth ratio of the beams used in these investigations was maintained as 2.0. The variables of study include the Characteristic strength of concrete, fck (15.0 MPa, 20.0 MPa, and 25.0 MPa) and polypropylene fibre (Recron 3s) content (0%, 0.5% and 1%). The polypropylene fibre and 20% of Fly ash as cement replacement are incorporated in all the concrete mix proportions considered in this study. The test results indicate that compressive strength of concrete increases with the increasing percentage of fibre. There has been a significant increase in flexural and shear strengths of PFRFAC, in all the mix proportions, as fibre content increased from 0% to 1.0%. However, the ultimate failure was observed to be gradual in all the beams.