Agro-industrial-based wastes as supplementary cementitious or alkali-activated binder material: a comprehensive review

An attempt to shed light on the use of agro-industrial-based wastes as supplementary cementitious material (SCM) or as alkali-activated binder (AAB) material is mainly focused in this review paper. The SCM or AAB acts as a suitable replacement for cement, as the cement manufacturing tends to contribute to 8–10% of global CO₂ emissions. To gain acceptability in the construction industry, diverse agro-industrial-based wastes must demonstrate their potential as precursors in AAB or as SCM. The binder materials discussed among the agricultural wastes are rice husk ash, olive waste ash, and coconut-based waste ash, and the industrial wastes are ground granulated blast furnace slag, fly ash, and ultra-fine steel slag. The paper also analyses the effects of calcined and uncalcined agro-industrial-based wastes on pozzolanic properties of binder system. It is clear from the studies that the calcined wastes tend to provide greater reactivity compared to the uncalcined wastes, that helps in early strength development in the binder system. The review findings indicate that the agro-industrial-based wastes provide pozzolanic and hydraulic properties, thereby making them suitable as an AAB or as a SCM.