Compressive strength and gel formation of enhanced geopolymer with addition of nanomaterials – a review

Abstract

Nanomaterial reinforcement has emerged as a pivotal strategy to overcome the mechanical and durability limitations of traditional geopolymer binders. This review systematically evaluates the integration of zero- to one-dimensional nanomaterials, like graphene oxide, carbon nanotubes, and nano silica, etc., into geopolymer matrices synthesized from diverse industrial precursors such as fly ash, slag, and red mud. The fundamental mechanisms of reinforcement, specifically nucleation, matrix densification, and micro-crack bridging, are analyzed to illustrate the transition from brittle to ductile behavior. Beyond mechanical enhancement, the critical roles of dispersion techniques, particle size, and optimal dosages in mitigating workability trade-offs and agglomeration are examined. This work delineates the relationship between microstructural evolution and crack-arrest mechanisms through a systematic evaluation of SEM, XRD, and Nanoindentation results reported in recent literature. Furthermore, the review explores innovative processing trends, such as the synergy between nano-additives and rapid microwave curing, which significantly reduces energy consumption compared to conventional thermal methods. Finally, industrial scaling challenges, cost-effectiveness, and the environmental life-cycle of nano-engineered composites are addressed. By identifying critical research gaps in multi-nanomaterial synergy and standardized durability testing, this paper provides a strategic roadmap for the development of high-performance, resilient, and sustainable geopolymer infrastructure.