Ciments

Ciments is the French term for cement, the binding powder used in construction. In general usage, cement refers to hydraulic binders that harden by hydration and bind aggregates to form concrete or mortar. The most common form is Portland cement, produced by grinding clinker with a small amount of gypsum.

Production starts with raw materials such as limestone and clay or shale, which are blended, ground, and fed to a kiln to form clinker at high temperatures. The clinker is then cooled and ground with gypsum to produce ordinary Portland cement. The chemistry of Portland cement centers on calcium silicates (notably C3S and C2S) and alumina and ferrite phases (C3A and C4AF); upon hydration these phases form calcium silicate hydrate and calcium hydroxide, creating a hard, binding matrix.

Types and standards: beyond ordinary Portland cement, blended cements incorporate fly ash, slag, or natural pozzolans. Standards such as EN 197-1 in Europe and ASTM C150 in the United States classify and specify cement types and properties.

Applications: cement serves as the binder in concrete and mortar, supporting infrastructure from buildings to roads and dams. Performance depends on the cement type, fineness, proportioning, and curing conditions.

History and environment: hydraulic cements have ancient precursors, but modern Portland cement was developed in the 19th century (named after Portland stone). Cement production is energy- and emissions-intensive; the industry uses supplementary cementitious materials, alternative fuels, and carbon capture to reduce CO2 emissions.