Next-generation green intelligent self-sensing geopolymer composites for enhancing construction security and sustainability: A review

In the context of the construction and buildings driving towards security and sustainability, there is an increasing demand for smart and green building materials. Self-sensing cement composites (SSCCs) have emerged as a viable solution, proving continuous real-time and in-situ time structural health monitoring (SHM). By using geopolymer as a green binder, self-sensing geopolymer composites (SSGCs) are emerging as a promising alternative to SSCCs, which traditionally using ordinary Portland cement (OPC) as binder. SSGCs are advantaged in lower-carbon emission, significantly enhanced corrosion resistance, and comparable or superior mechanical strength compared to SSCCs. Their unique composition and microstructure, characterized by high alkali ions concentrations from activators and a large number of micropores, endow SSGCs with exceptional electrical conductivity and sensing properties. This paper presents an in-depth review of the latest research, focusing on the intrinsic characterizations, properties and mechanisms of SSGCs, with particular emphasis on the conductive and sensing mechanisms arising from the composition interaction and pore characteristics. It also discusses the challenges and future perspectives in terms of manufacture and application for SSGCs. Their development is pivotal for bolstering structural security, enhancing construction sustainability and minimizing maintenance costs, marking a substantial leap towards a next-generation green intelligent infrastructure.