Behaviour of Concrete Beams Reinforced with PP Fibres and GFRP Bars Exposed to Marine Environment Conditions

This work describes the experimental research activity executed to develop and evaluate the potential of new reinforcement solutions for concrete structures in marine environment conditions. For this purpose, four series of small-scale beams were tested in three-point loading configurations to determine the influence of polypropylene fibres (PP) on the shear capacity of these beams, and the flexural reinforcement efficiency of glass fibre reinforced polymer (GFRP) bars. The partial use of recycled aggregates, as well as the use of seawater on the production of the concrete was also explored in an attempt of developing a more sustainable material, by taking the advantage of the corrosion-immunity of the adopted reinforcements. Reinforced concrete (RC) beams were made by two types of concrete reinforced with PP fibres (PPFRC1 and PPFRC2), and one plain concrete (PC). The mechanical properties at different ages in the hardened state of the developed FRC and PC were determined to derive the fundamental information for modelling the structural behaviour of the tested RC beams. Besides the force mid-span deflection, the crack patterns and failures modes were registered. Reference beams flexurally reinforced with steel bars were also tested for comparing the efficiency of GFRP and steel bars in terms of stiffness, load carrying capacity and deflection performance. Additionally, the shear resistance of RC beams was estimated by using the formulations of RILEM TC 162-TDF and fib Model Code 2010. The relevant results are presented and discussed in this paper.