Compressive performance of polyurethane bonded basalt-plastic-rubber porous composite paving material

This study presents the development and optimisation of a sustainable polyurethane (PU)-bonded basalt-plastic-rubber composite for paving applications, addressing the ecological concerns associated with traditional asphalt and concrete. By integrating basalt aggregates with recycled plastic and rubber in a PU binder, the research aims to deliver an eco-friendly alternative that balances mechanical performance with environmental sustainability. Quasi-static compression testing was used to characterise the elastic modulus, yield strength, and ultimate strength of the composite material, while X-ray computed tomography (XCT) analysis confirmed a porosity range of 24.21 %–25.83 %, ensuring adequate permeability for water drainage. The influence of the proportion of basalt, plastic and rubber was characterised through the development of a mixture-model capable of predicting the mechanical performance of the composite sample representing a novel contribution to the field. The mixture-model also revealed the influence of basalt, plastic and rubber distribution within the PU matrix on the stiffness and strength of the composite. This approach enables the development of composite material with targeted performance simply by varying the material composition within the PU matrix. The optimal composite formulation of 60 vol % basalt, 20 vol % plastic, and 20 vol % rubber, derived from mixture modelling and ANOVA analysis, yielded superior mechanical properties achieving an elastic modulus of 37.84 MPa and strength of 1.01 MPa, offering a sustainable paving material. This work offers insights into the mechanical interplay of sustainable composite mixture materials for various paving applications.