Technical and Eco-Efficiency Implications of the Use of Basalt Fibre in Hybrid Composites

The use of hybrid composites can be environmentally friendlier than the traditional materials since renewable resources, both natural and synthetic fibres can be incorporated into the composites, resulting in lighter weight, enhanced resource efficiency, durability, and biodegradability, which could potentially make them sustainable materials for structural applications. Basalt fibre being treated with hydrochloric acid exhibits superior adhesion with the epoxy matrix, improving overall strength and stiffness. Thus, the aim of this paper is to determine the eco-efficiency of two types of hybrid composites: glass/basalt and carbon/basalt fibre-reinforced under flexural loading. The flexural strengths of these composites were obtained through a Finite Element Analysis (FEA) model using Ansys workbench. These simulation-based flexural strengths form the basis for the quadratic regression model to establish a relationship between the different flexural strengths and fibre volume fractions combinations. Given the required flexural strength between 900 and 1300 MPa, the optimal candidates/layups were identified with the aid of the model. An environmental study following a life cycle assessment (LCA) and eco-efficiency framework of unidirectional glass/basalt and carbon/basalt fibre-reinforced hybrid composites with varying fibre volume fractions is presented in this paper to select the eco-efficient composites. In the case of glass/basalt fibre-reinforced hybrid composites, the designs with the highest eco-efficiency for 900 and 1200 MPa are [BG3]S with more glass fibre and [G7B] with more glass fibre, respectively, due to having lower costs and environmental impacts. For carbon/basalt fibre-reinforced composites, the stacking sequence [B8] was deemed to be the most eco-efficient. Finally, epoxy has the highest economic and environmental cost. Therefore, composite designs with high glass fibre content are considered eco-efficient since they have a lower epoxy content.