Basalt Fiber‐Reinforced Thermosetting Polymer Composites: A Critical Review of Fiber Properties, Interfacial Engineering, Hybridisation, Durability, and Applications

ABSTRACT Basalt fiber‐reinforced polymer (BFRP) composites have emerged as a promising, environmentally responsible alternative to conventional glass fiber (GF) and carbon fiber (CF) composite systems. Produced from natural volcanic basalt rock without chemical additives or toxic by‐products, basalt fiber combines good mechanical properties, strong chemical resistance, and a wide thermal service range with a substantially lower environmental production footprint than conventional synthetic reinforcement fibers. When combined with thermosetting polymer matrices, such as unsaturated polyester (UPR), vinyl ester (VER), or epoxy systems, BFRP composites offer structural performance competitive with glass fiber‐reinforced polymer composites, alongside meaningful sustainability and cost advantages, making them attractive across a broad range of engineering sectors. This review critically evaluates the current state of knowledge on BFRP composites with thermosetting matrices, emphasising mechanistic interpretation of structure–property relationships rather than compiling descriptive data. This review critically analyses thermosetting matrix formulation, fiber surface treatment, hybridisation architectures, and multi‐scale morphological characterisation. A key finding is the identification of hybrid UPR/VER matrix systems as a scientifically important but largely unexplored research direction. Engineering applications across the aerospace, automotive, civil infrastructure, marine, and renewable energy sectors are examined with direct linkage to material properties and performance advantages. Future research priorities, including artificial intelligence‐assisted materials design, bio‐based thermosetting matrices, recyclable thermoset systems, in situ structural health monitoring, and multi‐scale computational modeling, are identified and discussed. This review is intended as a comprehensive and accessible reference for researchers and engineers advancing the fundamental science and practical deployment of next‐generation BFRP composite systems.