Ingredientscement

Ingredientscement refers to the components used to make cement, a binding material in concrete. The most common type, Portland cement, combines numerous inorganic compounds produced by calcining raw materials and is used worldwide.

The primary raw materials are calcareous rock (limestone or chalk) and siliceous and/or aluminosilicate materials such as clay and shale. These are heated in a kiln to form clinker, a nodular material whose main components are calcium silicates (alite C3S and belite C2S), calcium aluminates (C3A) and calcium aluminoferrites (C4AF). Gypsum is added during grinding to regulate the setting time.

In addition to clinker and gypsum, many cement varieties include supplementary cementitious materials (SCMs) such as fly ash, ground granulated blast furnace slag (GGBFS), or natural pozzolans. These materials can partly replace clinker and modify properties like strength development, durability, and heat of hydration. Lime-based hydraulic cements and other binders are also used in specialized applications.

Admixtures and additives may be incorporated to improve workability, setting time, or durability. Examples include plasticizers, air-entraining agents, accelerators, and retarders. The exact mix depends on performance requirements and standards.

Cement ingredients are subject to regulatory standards that define composition and performance, such as ASTM C150 in the United States or EN 197-1 in Europe. The production and use of cement have environmental impacts, notably CO2 emissions from calcination and fuel combustion, prompting ongoing development of blended cements and alternative materials.