Alkali-activation is a technically sound pathway to valorize industry wastes and by-products, and there has been a burgeoning interest in evaluating the potential of waste streams and/or by-products from different industries as precursors for alkali-activated materials production. In the context of sustainable construction materials, as well as other industrial systems, the use of such non-conventional precursors addresses the challenges associated with the global availability and management of such resource streams. This includes the availability of alternative valorisation routes, the life cycle implications of using waste streams, and the pragmatic issues around incorporating a wide range of precursor materials for future proof this technology. In this chapter an overview of studies utilizing alternative precursors for producing alkali-activated cements is presented, analyzing the characteristics of each resource, and identifying the links between mix design formulations and the performance of the alkali-activated materials produced with them. This in order to elucidate the existing knowledge gaps to facilitate the widespread uptake of such resources as key precursors for producing this type of cements.

Among the various examples of sustainable construction materials explored in scientific literature, alkali-activated materials excel as one of the most mature and reliable solutions for large scale applications. It consists on the combination of an alkaline source in liquid or solid state, and a partially-to-fully amorphous solid precursor. The combination of these components leads to the obtainment of a hardened material which resembles Portland-cement based products. The performance and durability of these alternative binders is highly dependent on their components and production methods, and multiple laboratorial- and industrial-scale examples have shown their capability of outperforming conventional building materials. Practical challenges with variations in chemistry and mineralogy of raw materials, and the global utilization of prescriptive standards for structural building materials, hinder a wider utilization of these binders, and the efforts of the scientific and applied industry communities in overcoming these barriers is detailed throughout this report. This chapter provides an overview of alkali-activated binders, summarizing the main characteristics of their components, their reaction mechanisms, their challenges, and the expected advances of the technology with respect to one-part binders.