Constitutive behaviour and modelling of hybrid basalt-polypropylene fibre-reinforced concrete considering coupling effect of fibre reinforcement and mechanical damage

The uniaxial compressive stress-strain behaviour of hybrid basalt-polypropylene fibre-reinforced concrete (HBPRC) having different matrix strengths was investigated. The results showed that basalt fibre (BF) and polypropylene fibre (PF) reduce the damage degree of concrete and gradually change the concrete failure mode from shear failure to longitudinal splitting failure. BF and PF improve the critical strain and peak stress of concrete, and the improvement effect of BF is greater than that of PF. However, addition of an excessive amount of hybrid fibre reduces the peak stress of concrete. BF addition increases the elastic modulus of concrete, whereas PF addition decreases it. Addition of an appropriate amount of hybrid fibre has a positive effect on the elastic modulus of concrete. The toughness of concrete increases with the addition of BF and PF and the increase in the matrix strength. When HBPRC is destroyed, BF mainly shows tensile failure, whereas PF mainly shows pull-out failure and undergoes extrusion and torsion deformation. BF and PF mainly improve the strength and deformation performance of concrete, respectively. A constitutive model for HBPRC that considers the effects of both mechanical damage and fibre reinforcement is established.

Automated summary

The uniaxial compressive stress-strain behavior of hybrid basalt-polypropylene fiber-reinforced concrete (HBPRC) with different matrix strengths was investigated in this study. The results showed that basalt fiber (BF) and polypropylene fiber (PF) reduced the damage extent of concrete and changed the failure mode from shear failure to longitudinal splitting failure. Both BF and PF improved the critical strain and peak stress of concrete, with BF having a greater improvement effect than PF. However, excessive addition of hybrid fiber decreased the peak stress of concrete. BF addition increased the concrete's elastic modulus, while PF addition decreased it. The addition of an appropriate amount of hybrid fiber had a positive effect on the concrete's elastic modulus. The toughness of concrete increased with the addition of BF and PF, as well as the increase in matrix strength. When HBPRC was destroyed, BF mainly exhibited tensile failure, while PF mainly exhibited pull-out failure and underwent extrusion and torsion deformation. BF and PF mainly improved the strength and deformation performance of concrete, respectively. A constitutive model considering the effects of both mechanical damage and fiber reinforcement was established for HBPRC.