Het cementachtige bindmiddel voor de meeste gestructureerde soorten beton, verkregen door het verpulveren van klinker die hoofdzakelijk bestaat uit hydraulische calciumsilicaten; bevat calciumsulfaat als meegemalen toevoeging.binding material in the form of a finely ground powder, usually gray, that is manufactured by burning and grinding a mixture of limestone and clay or limestone and shale. The cementitious binder for most structural concrete; obtained by pulverizing clinker consisting essentially of hydraulic calcium silicates; contains calcium sulfate as an interground addition. When mixed with water, the anhydrous calcium silicates and other constituents in the portland cement react chemically with the water, combining with it (hydration) and decomposing in it (hydrolysis) and hardening and developing strength. Joseph Aspdin, of England, patented the basic process in 1824, naming it for the resemblance of the cement when set to portland stone, a limestone from the Isle of Portland.形態為精細研磨之粉末的黏接用材料，一般而言是灰色的，係藉由燃燒和磨碎石灰石和黏土或者石灰石和頁岩的混合物製成，是大部分結構用混凝土工程中使用的黏接劑。波特蘭水泥是將基本上由水硬性矽酸鈣構成的熟料研磨成粉末後取得，其中會添加硫酸鈣一起研磨製作。在與水混合之後，無水的矽酸鈣和波特蘭水泥中的其他成分就會和水產生化學反應，發生水合、水解作用，並且硬化產生強度。英國的約瑟夫‧阿斯普丁（Joseph Aspdin）在1824年以製作這種材料的基本方法取得專利，並且因為這種水泥硬化之後和來自波特蘭島（Isle of Portland）的石灰石「波特蘭石」很類似，而將之命名為波特蘭水泥。Elemento de mezcla cementosa de la mayoría de los hormigones estructurales; obtenido pulverizando una escoria formada fundamentalmente por silicatos de calcio hidráulicos. Contiene sulfato de calcio como añadido básico.