Nanotechnology in cement-based materials: A state-of-the-art review on performance enhancement, sustainability challenges, and future prospects

The cement industry faces urgent demands for innovative solutions to mitigate its significant environmental footprint. Nanotechnology offers a promising pathway to develop high-performance and multifunctional cement-based materials, addressing both performance enhancement and sustainability challenges. This review critically examines the mechanisms by which key nanomaterials, including nano-SiO 2 , nano-CaCO 3 , carbon nanotubes, and graphene oxide, regulate cement hydration and refine microstructure, leading to notable improvements in compressive strength, fracture energy, and chloride permeability reduction. Beyond mechanical and durability gains, emerging functionalities such as self-cleaning and sensing capabilities are highlighted. The discussion extends to environmental implications, analyzing carbon emission reduction potential through cement minimization and waste valorization, while addressing unresolved issues like nanomaterial ecotoxicity and the need for comprehensive life-cycle assessments. Despite progress, key challenges remain, including dispersion difficulties, long-term stability in alkaline environments, and high costs. Future advances hinge on the development of low-cost waste-derived nanomaterials, intelligent dispersion techniques, and multifunctional composites, supported by multiscale modeling and machine learning for rational design. This work outlines a comprehensive roadmap toward intelligent, sustainable, and eco-efficient cementitious composites for next-generation infrastructure. • The influence of nanomaterials on cement properties and microstructure is summarized. • The advantages and challenges of nanomaterials application in cement are analyzed. • Future research and development directions for nanomaterials in cement are discussed.