#Portland cement is the most common type of cement in general #usearoundtheworld, used as a #basic ingredientof concrete, #mortar,stucco, and most non-speciality grout. It was developed from other types of #hydraulic lime in England in the mid 19th century and usually originates from limestone. It is a fine powder produced by #heatingmaterials in a #kiln to form what is called clinker, grinding the clinker, and adding small amounts of other materials. Several types of Portland cement are available, with the most common being called ordinary Portland cement (OPC) which is grey in color, but a white Portland cement is also available.
Portland cement is caustic, so it can cause chemical burns. The powder can cause irritation or, with severe exposure, lung cancer and can contain some hazardous components such as crystalline silica and hexavalent chromium. Environmental concerns are the high energy consumption required to mine, manufacture, and transport the cement and the related air pollution, including the release of greenhouse gases(e.g., carbon dioxide), dioxin, NOx, SO2, and particulates.
The low cost and widespread availability of the limestone, shales, and other naturally occurring materials used in Portland cement make it one of the lowest-cost materials widely used over the last century throughout the world. Concrete produced from Portland cement is one of the most versatile construction materials available in the world.
Portland cement was developed from natural cements made in Britain beginning in the middle of the 18th century. Its name is derived from its similarity to Portland stone, a type of building stone quarried on the Isle of Portland in Dorset, England.
The development of modern Portland cement (sometimes called ordinary or normal Portland cement) began in 1756 when John Smeaton experimented with combinations of different limestones and additives, includingtrass and pozzolanas, relating to the planned construction of a lighthouse now known asSmeaton's Tower. In the late 18th century,Roman cement was developed and patented in 1796 by James Parker; Roman cement quickly became popular, but was largely replaced by Portland cement in the 185