Toward Energy-Efficient Building Systems: A Comprehensive Review of Silica Aerogel–Cement Composites

Silica aerogels (SA) exhibit exceptional thermal insulation, extremely low density, and ultra-high porosity, making them promising additives for developing energy-efficient cementitious composites. However, incorporating SA into cement matrices often results in reduced mechanical performance, weakened interfacial bonding, and concerns about long-term durability. This review provides a structured and critical evaluation of research published between 2000 and 2025 on SA-enhanced cement-based materials. A systematic review methodology was adopted, using the Scopus, Web of Science, and ScienceDirect databases, to evaluate synthesis routes, incorporation methods, and performance outcomes. The paper provides a comprehensive overview of advances in SA-enhanced cementitious composites, with particular emphasis on their thermal insulation efficiency, fresh-state behavior, mechanical performance, and long-term durability. Despite considerable progress, current research remains fragmented in terms of structure–property relationships, performance optimization, and standardized evaluation protocols. This work highlights a major research gap in establishing consistent methodologies for assessing durability and optimizing mechanical-thermal synergy for practical applications. The objectives of this review are to consolidate existing knowledge, identify critical challenges, and propose strategic directions for enhancing the performance, scalability, and sustainability of SA-cementitious composites. The review also discusses recent innovations, including nanosilica, recycled PET fibers, graphene oxide, carbon nanotubes, and silane surface modifications, which aim to mitigate strength loss while preserving insulation benefits. Overall, this study underscores the necessity for interdisciplinary research to develop robust, cost-effective, and durable aerogel-based cementitious materials for sustainable construction.