Dynamic mechanical properties, interface structure evolution and deformation behaviors of PVA-carbon fiber reinforced concrete with negative Poisson’s ratio design

Based on the advantages of negative Poisson's ratio (NPR) materials in controlling deformation and absorbing energy, this paper combines NPR design with the preparation of fiber reinforced concrete (FRC) to optimize the anti-dynamic load performance of FRC. In this paper, a helical auxetic yarn (Hay) with NPR effect is obtained by wrapping carbon fiber (CF) on polyvinyl alcohol fiber (PVAF) at a certain angle, and it is mixed into concrete in different forms to obtain auxetic fiber concrete. In order to explore the influence of auxetic fiber on the anti-dynamic load performance of concrete, split Hopkinson pressure bar (SHPB) test and dropping ball impact test are carried out on different FRC. The impact resistance of FRC under different impact velocities is tested, and the impact resistance behavior of FRC is analyzed by digital speckle correlation method (DSCM). The results show that in SHPB test, the anti-impact strength of the layered auxetic fiber concrete is 19.1 % higher than that of the plain concrete (PC), and its fracture energy is increased by 25.8 %. In the dropping ball impact test, its fracture energy is 5 ∼ 9 times that of PC. In addition, the results of scanning electron microscopy (SEM) and DSCM test show that the incorporation of auxetic fiber has a positive effect on improving the generation and development of internal cracks in concrete, which is expected to provide a reference for the application of NPR materials in explosion resistance, penetration resistance and impact resistance of building structures.