Portland cement (CEM I) / Ordinary Portland cement (OPC)

Basis (95 – 100 %) and name-giver of this fast curing and high quality cement is limestone from the English peninsula Portland (denomination acc. to DIN 1164-1/EN 197-1: CEM I). With other additions up to a maximum of 5 %, as e.g. mart lime, alumina/clay, iron oxide, the limestone is burnt into Portland cement clinker and later ground to Portland cement of cement class CEM I. Any further additions lead to a classification into cement class CEM II – Portland composite cements –