Blended cement refers to a class of cement that incorporates one or more supplementary cementitious materials (SCMs) such as fly ash, slag, silica fume, or natural pozzolans to improve certain properties of the concrete. The blending aims to enhance the performance of the cement in fresh and hardened states while reducing the environmental impact associated with pure Portland cement manufacturing. The mechanisms behind the benefits of blended cements involve the chemical reactions between SCMs and the by-products of Portland cement hydration, leading to additional formation of calcium silicate hydrate and other beneficial compounds.