Alkali-activated cement (AAC) is a type of cementitious material that is produced by activating aluminosilicate-rich materials with an alkaline solution. Unlike traditional Portland cement, which is based on the hydration of calcium silicates, AAC relies on the reaction of materials like fly ash, slag, or natural pozzolans with an alkaline activator (commonly sodium or potassium silicate). This reaction forms a gel that binds aggregates together to form concrete. The process can be tailored to use a variety of waste materials, promoting sustainability.