Aluminosilicate sources, such as fly ash, metakaolin, and slag, play a crucial role in the formulation of alternative cementitious materials, particularly in the production of geopolymers and alkali-activated cements. These materials are derived from natural and industrial byproducts containing high amounts of silica and alumina, which are key to facilitating the chemical reactions necessary for producing durable and sustainable cementitious binders. Utilizing aluminosilicate sources in cement and concrete not only helps in reducing the carbon footprint associated with traditional Portland cement but also enhances the material’s performance in severe environmental conditions, including high moisture, chemical exposure, and extreme temperature fluctuations.