A literature review of the latest trends and perspectives regarding alkali-activated materials in terms of sustainable development

Abstract

The purpose of the paper was to analyze trends in the formation of alkali-activated materials (AAMs) produced from alternative starting materials to blast furnace slags and fly ash. The research was reviewed on the basis of literature data from the past few years, which shows that the researchers are increasingly paying attention to the possibility of synthesis of AAM from such waste materials as industrial slags and ashes, concrete and demolition waste, red brick waste and glass waste. This is driven by the need to find competitive solutions to the commonly used blast furnace slags and fly ashes in the cement industry, which are also a source for obtaining traditional AAM. Analysis of material solutions has shown that these materials are being successfully used to produce new AAMs, with most of them being only a partial replacement for slags and fly ash. The article also points out that silicon- and aluminum-rich waste materials such as red mud, rice husks, and waste glass can be successfully used to activate AAMs materials, in place of typical activators in the form of sodium silicates or hydroxides, which in turn contributes to lowering the carbon footprint of AAMs. However, the future of this type of solution depends on several factors, the most important of which seems to be the understanding of the polymerization mechanisms of the more complex aluminosilicate systems and the achievement of reproducible physical and chemical parameters of AAM, resulting in strong and durable binders and, ultimately, construction materials made from them.