Portland cement

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, and then grinding the clinker with the addition of several percent (often around 5%) gypsum. Several types of portland cement are available. The most common, historically called ordinary portland cement (OPC), is grey, but white portland cement is also available.

The cement was so named by Joseph Aspdin, who obtained a patent for it in 1824, because, once hardened, it resembled the fine, pale limestone known as Portland stone, quarried from the windswept cliffs of the Isle of Portland, a presque-isle off the Dorset coast. Portland stone was prized for centuries in British architecture and used in iconic structures such as St. Paul’s Cathedral and the British Museum.

His son William Aspdin is regarded as the inventor of "modern" portland cement due to his developments in the 1840s.^[1]

The low cost and widespread availability of the limestone, shales, and other naturally occurring materials used in portland cement make it a relatively cheap building material. At 4.4 billion tons manufactured (in 2023), Portland cement ranks third in the list (by mass) of manufactured materials, outranked only by sand and gravel. These two are combined, with water, to make the most manufactured material, concrete. This is Portland cement's most common use. ^[2]