Belite

Etymology: Named by Törnebohm in 1897 Belite is common in the cement industry Derived from Larne, Northern Ireland Occurs naturally as larnite Discovered near Scawt Hill Composition and Structure: Belite in Portland cement differs from pure dicalcium silicate Contains minor amounts of other oxides Typical composition includes CaO and SiO Formula expressed as Ca1.94Si0.02O5 Composition varies with clinker bulk composition Polymorphs: Stable dicalcium silicate Lowtemperature form is γbelite Rapid reaction similar to natural hydration of forsterite Hydrate phase referred to as CSH phase Rapid cooling needed to avoid γform Detection: Minerals in Portland cement clinker observed by petrographic microscopy Clinker nodules cut and ground for observation Minerals made visible by etching the surface Belite appears as blue under optical microscopy Xray diffraction preferred for accurate mineral quantification See Also: Hydration reaction of forsterite in serpentinisation CCN, cement chemist notation References: JeanPierre Bournazel et al., 1998, Concrete, from Material to Structure Deer et al., 1997, Larnite. Disilicates and ring silicates Taylor H.F.W., 1990, Cement Chemistry