Experimental research on mechanical performance of reactive powder concrete beams reinforced with GFRP bars

To study the mechanical properties of GFRP bars reinforced RPC beams, tests of eight GFRP bars reinforced RPC beams were carried out. The mechanical properties such as cracking moment, ultimate moment, stiffness and cracks were studied by the one-third point loading tests. The test results show that the favorable influence of longitudinal GFRP reinforcement on cracking moment and plastic coefficient should be considered. The cracking strain (750 × 10^-6) at the pure bending section of RPC beams is seven times of that of the ordinary concrete beams. There are three types of cross-sectional failure patterns of GFRP bars reinforced RPC beams. The tension failure is that the longitudinal GFRP reinforcement fractures while the concrete at compressive edge of the PRC is not crushed. The compression failure is that the concrete at compressive edge of the PRC is crushed (5500 × 10^-6) while the longitudinal GFRP reinforcement does not fracture. The limit failure is that the rupture of the longitudinal GFRP reinforcement and the crushing of the concrete at compressive edge of the PRC occur at the same time. Under compression failure, the contribution of tensile stress to the flexural strength may be considered based on 0.25 times the RPC tensile strength. For tension failure, the flexural strength can be calculated by numerical iterative procedure based on the stress-strain relationship of materials. The key to the calculation of stiffness and crack width is the calculation of GFRP reinforcement tensile stress at service stage. The moment used in the calculation of GFRP reinforcement tensile stress should be the external moment minus the moment of resultant tensile stress of RPC tensile stress in tensile region to resultant point of compression region.