Dynamic compressive behaviour of hybrid basalt-polypropylene fibre-reinforced concrete under confining pressure: Experimental characterisation and strength criterion

Abstract The dynamic compressive behaviour of hybrid basalt-polypropylene fibre-reinforced concrete (HBPRC) under confining pressure was investigated using a Hopkinson compression bar device with active confining pressure. The relationship between the pore structure and the dynamic compressive behaviour of HBPRC was discussed. The results indicate that the dynamic compressive behaviour of HBPRC under confining pressure shows evidently the strain rate dependence and the confining pressure dependence. The addition of basalt fibre (BF) and polypropylene fibre (PF) reduces the failure degree of concrete and improves the shear failure feature. The relationship between the pore surface fractal dimension and the strain rate effect of HBPRC indicates that the dynamic mechanical properties of HBPRC are affected not only by the fibre itself but also by the effect of fibre on the pore structure. In view of strengthening and toughening, BF is conducive to increasing the strength of HBPRC, whereas the PF is conducive to improving the toughness. Finally, based on the Hoek-Brown strength criterion, an empirical dynamic strength criterion for HBPRC accounting for the effect of fibre and pore structure is established and verified.