Rice husk Ash-Based Self-Compacting geopolymer concrete: a systematic and scientometric review

Rice husk ash (RHA), a silica-rich agricultural by-product, is a promising reactive precursor in alkali-activated systems, supporting circular economy goals and reducing construction’s carbon footprint. This study delivers a systematic scientometric review of RHA-based self-compacting geopolymer concrete (SCGC), combining bibliometric mapping with mechanistic analysis to identify knowledge gaps. Bibliometric trends show accelerating global interest dominated by compressive strength and sustainability, while rheological optimisation, ambient curing, and durability modelling remain comparatively underexplored. RHA enhances geopolymerization by improving silica availability, regulating the Si/Al ratio, and refining pore structure at 5–15% replacement, with higher dosages aiding durability in calcium-rich blends; however, its high surface area raises water demand and viscosity, complicating self-compacting flowability. Because RHA quality varies with source and processing, replacement level alone cannot reliably compare mixtures across studies, and the coupling between RHA reactivity, rheology, and self-compaction remains insufficiently synthesised. This review addresses these gaps by proposing a performance-based mix-design framework and a preliminary RHA quality-classification approach, and by identifying where durability, ambient-curing, and techno-economic evidence remain incomplete. RHA-based SCGC holds strong promise as a biomass-valorized material, yet multidisciplinary integration of materials science, rheology, durability engineering, and life-cycle assessment remains essential for reliable large-scale deployment.