Industrial and C&D waste as precursor material in geopolymers: a state-of-the-art review

In the wake of heightened environmental concerns, with a focus on reducing CO₂ emissions, the construction industry is actively seeking alternative materials to traditional cement. This need for a holistic, sustainable infrastructure paved the path for an inorganic polymer-based technology, i.e., geopolymer production. Geopolymers require aluminosilicate source material for their products, which can be both naturally available materials (i.e., kaolin, volcanic ash, rice husk ash) or waste materials (i.e., fly ash, slag, construction and demolition waste). A huge amount of research work has been conducted on geopolymer production by using different aluminosilicate source materials, mostly construction and demolition (C&D) waste in the last one-two decades. Hence, this review article attempts to provide a state-of-the-art review of the most recent developments in the field of geopolymers utilizing industrial and C&D waste. The present article explores and summarizes the work conducted by various researchers on the utilization of different industrial waste such as fly ash, Blast furnace slag, etc. and also explores various components of C&D waste i.e., brick, cement concrete, glassware, and ceramics. It includes the inception of geopolymers, rheological properties of different waste, and mechanical and durability properties. Construction and demolition waste with high calcium and alumina content boosts geopolymerization and improves the mechanical properties at ambient temperature curing and lowers the efflorescence.