Behavior of reinforced concrete beam strengthened by HPFRCC material

High performance fiber reinforced cementitious composites (HPFRCC) are cement matrices with strain hardening behavior under tension loading. In these composites, the cement mortar with only fine aggregates is reinforced by random distributed fibers. In this material, multiple cracking in the HPFRCC occurs due to bridging mechanism of the fibers and subsequently, the strain hardening behavior is observed. In this paper, based on an experimental work, HPFRCC layers with different thicknesses and different lengths are used in lieu of normal concrete. Compressive and tensile strengths of the HPFRCC material are variable in these analytical models too. Finite element approach is used to investigate the effect of these parameters on the capacity of the reinforced concrete beam. Results show that increasing the compressive and tensile strength of the HPFRCC layers concludes to more final load and more ductility of the analytical beams. But this increasing effect is not significant. Moreover, increasing the thickness and length of the HPFRCC material concludes to more final load and more ductility in the retrofitted models. The ductility of the full HPFRCC beam is about 1.39 times more than that of the reinforced concrete beam.