Tensile and flexural performance of concrete members reinforced with polypropylene fibers and GFRP bars

In the present study, an experimental program was carried out to evaluate the influence of the addition of 10 kg/m(3) of polypropylene (PP) fibers on the tensile and flexural behavior of concrete members internally reinforced with GFRP bars. Mechanical characterization and pullout tests were performed to determine the properties of the constituent materials and to characterize their interface. In a structural level, direct tensile and four-point bending tests were performed on prismatic specimens to investigate their mechanical response. Throughout the work, digital image correlation (DIC) was used to monitor deformations, crack openings and spacings. A considerable reduction in cracking width and an increased multiple cracking behavior was observed for specimens with fiber addition. The results show also a significant influence of tension-stiffening for specimens subject to tension and bending, whereas a slight increase in structural ductility was observed for the specimens tested in bending. The tests indicate possible influence of the shear lag effect to the bar stiffness.