Fracture characteristics of plain and steel fibre reinforced rubberized concrete

•Rubberized mixes prepared by inclusion of a blend of crumb rubber aggregate as a partial replacement of sand in plain and steel fibre concrete.•An instigation of the fracture toughness properties of steel fibre reinforced rubberized concrete is presented considering various ratios of crumb rubber aggregate blend.•The addition of the crumb rubber aggregates considerably develops the fracture energy of plain concrete up to 246%, particularly with the hooked-end steel fibre.•Furthermore, the elastic–plastic fracture toughness parameter significantly increases with the rubber increase.•Based on obtained results, the crumb rubber aggregate ratio should not be more than 20% by replacement of sand volume. This study investigates the effect of recycled crumb rubber aggregates on the fracture characteristics of both plain concrete (PC) and steel fibre concrete (SFC) as a potential solution of the problem of discarded tires and due to the capacity of rubber aggregates to absorb high fracture energy. The variables considered in the experimental work are the concrete type (i.e., plain and steel fibre concrete) and the crumb rubber aggregate content as replacement ratios (i.e., 5%, 10%, 15%, 20%, and 25%) by volume of sand. The steel fibre used is a hooked-end fibre with an aspect ratio of 80 and a diameter of 0.75mm with a constant volume of 0.5%. The mechanical properties, fracture energy, stress intensity factor, critical strain energy release rate, elasticplastic fracture toughness parameter, and characteristic length of plain and steel fibre reinforced rubberized concrete are considered herein. Results show enhanced fracture characteristics induced by the crumb rubber inclusion in plain concrete. Further enhancement was observed by combination of steel fibre and crumb rubber aggregate in concrete. In addition to promote healthy environment using recycling waste tires.