As the world's second-largest alumina producer and the fourth-largest coal producer, Australia generates approximately 30 million tonnes of red mud (a byproduct of the Bayer process for alumina production) and 13 million tonnes of coal combustion products (fly ash and bottom ash) annually. While the recycling rate for coal combustion products in Australia is approximately 60%, the recycling rate for red mud (RM) is below 5%. This results in an increasing waste stockpile and poses a burden on the local environment. Therefore, there is a pressing need to find a sustainable solution for managing this expanding industrial waste stream.

Geopolymer, as an alternative binder to traditional cement, offers improved sustainability due to its ability to utilize various industrial wastes as aluminosilicate precursors (APs). Extensive studies have predominantly verified the feasibility of using various types of industrial waste, including coal combustion products and RM, for geopolymer production. Therefore, the utilization of these local industrial byproducts in Australia for geopolymer production is becoming increasingly attractive, as it promotes both a circular economy and the valorisation of local industrial waste.

The extreme variability in the inherent properties of these waste materials, however, including their chemical composition, particle size, and crystalline/amorphous phases, presents a significant obstacle to the wider application of geopolymer and hinders the valorisation of waste materials. To enable industrial-scale production, widely accepted standards for testing methods and material properties are crucial. These standards ensure the stability of the raw-material supply chain and the performance of the final product. [...]