Strengthening of concrete beams by monolayer prepreg composites with and without graphene reinforcement

Composite materials are widely used in different engineering fields and they are very efficient for engineering applications. Several composite materials are in use along with the technological innovations in materials and construction techniques. This study focuses on the monolayer prepreg (MP) composites and graphene-reinforced monolayer prepreg (GMP) composites and their structural contribution to the structural performance of concrete beams. The main objectives of the study are (1) to understand the mechanical properties of the MP and GMP composites, (2) to investigate the influence of graphene on the mechanical characterizations of the MP composites and (3) to compare the strengthening effectiveness and configurations of the MP and GMP composites applied to plain concrete (PC) beams. For this purpose, the MP and GMP composites are produced as continuous sheets and concrete beams are strengthened with these sheets considering four different internal and external strengthening configurations. The flexural behavior of the PC beams is compared to reinforced beams with MP and GMP composites through experiments, numerical simulations and statistical tests. The results indicate that the tensile strength of the MP composite increases by addition of graphene leading to more effective strengthening by the GMP composites, especially with external configuration, than the MP composites.