Post-cracking behaviour of basalt and macro polypropylene hybrid fibre reinforced concrete with different compressive strengths

•New hybrid fibre reinforced concrete is introduced with significantly difference in young modulus.•A new failure mode was observed and a new behaviour classification was introduced for hybrid fibre reinforced concrete (FRC).•FRC with different concrete strengths (30 MPa and 60 MPa) were investigated. This study experimentally investigated the mechanical properties of basalt-macro polypropylene hybrid fibre reinforced concrete. Three macro polypropylene fibre volume fractions (0.3%, 0.7% and 1%), two concrete compressive strengths (30 MPa and 60 MPa) and basalt fibre volume fraction 0.1%, were used to study their influences on the slump, compressive strength and flexural capacity of fibre reinforced concrete. A new failure mode was observed and a new behaviour classification was introduced for hybrid fibre reinforced concrete. The hybrid fibre reinforced concrete containing 0.1% basalt fibres and 1% macro polypropylene fibres showed excellent flexural strength, initial post-cracking strength and energy absorption as compared to plain concrete. The fracture energy of concrete had a significant influence on the post-cracking response of fibre reinforced concrete and thus concrete with different strengths showed distinguished behaviours. Both the C30 and C60 grade concrete showed that using hybrid basalt and macro polypropylene fibres could achieve approximately 10% and 20% improvement of the compressive strength and flexural strength, respectively.