Structural lightweight concrete for seismic-resistant and sustainable construction: a state-of-the-art review of material innovations and performance evolution

Abstract Structural lightweight concrete (SLWC) has gained increasing attention as a sustainable and earthquake-resilient construction material due to its optimal balance between reduced density and satisfactory mechanical performance. Compared with normal-weight concrete, SLWC generally achieves a 25–35 % reduction in density, typically 1,600–2000 kg/m 3 , while maintaining compressive strengths of approximately 17–60 MPa in well-designed systems. This reduction in self-weight leads to lower dead loads, enhanced structural efficiency, and a 20–30 % decrease in seismic base shear demand, thereby improving overall seismic performance. Recent developments highlight the synergistic use of lightweight aggregates with supplementary cementitious materials (SCMs), including metakaolin (MK), ground granulated blast-furnace slag (GGBFS), and limestone calcined clay (LC 3 ), commonly replacing 10–50 % of ordinary Portland cement. When combined with polymeric or natural fibers, these systems demonstrate improved strength development, durability, and post-cracking ductility, resulting in superior energy dissipation capacity under seismic loading. This review critically examines advances in SLWC by focusing on material innovations and microstructural characteristics and their influence on mechanical and seismic behavior. Sustainability performance is evaluated through embodied carbon and life cycle assessment (LCA) studies, reporting CO 2 emission reductions of approximately 15–40 % relative to conventional concrete.