Hybrid use of supplementary cementitious materials, industrial byproducts, and fillers for sustainable high-performance concrete

The growing need to reduce the environmental footprint of concrete has intensified research on supplementary cementitious materials, fillers, and industrial by-products. While the benefits of individual admixtures are well recognised, their synergistic integration offers a more powerful pathway for sustainable and high-performance concretes. This review consolidates advances in hybrid binder-aggregate-fibre systems, examining their mechanical behaviour, durability, microstructural features, and lifecycle performance. Synergistic use of pumice and silica fume delivers compressive strengths above 100 MPa with improved stiffness, while rubber-steel fibre concretes enhance fracture toughness by about 40% and improve impact resistance. Perlite-fibre composites reduce density by more than one-third while retaining structural-grade strength, and limestone-calcined clay cements lower carbon dioxide emissions by around 40% with superior chloride and sulphate resistance. Fly ash-steel fibre systems improve tensile strength, shrinkage control, and freeze-thaw durability, while polypropylene fibre-silica fume combinations limit plastic shrinkage cracking and refine the matrix. Hybrid binders also show resilience against combined chemical and mechanical degradation, such as acid-abrasion exposure. Lifecycle assessments confirm reductions in global warming potential of 30 to 60% in ternary and quaternary systems, with strength-normalised analyses reporting up to 75% reductions in rubberised concretes. Recycling-oriented pathways, including water treatment sludge, recycled aggregates, and construction and demolition waste, further strengthen the sustainability case while preserving mechanical efficiency. Microstructural investigations consistently highlight densification of the interfacial transition zone, refinement of pore structure, and improved crack bridging. Collectively, the synthesis shows that hybrid systems overcome the shortcomings of single-component materials while enabling circularity and decarbonisation, with future adoption requiring codal inclusion, standardised mix designs, and performance-based life cycle assessments.