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.

Hydraulic cements (e.g., Portland cement) set and become adhesive due to a chemical reaction between the dry ingredients and water.

It was developed from other types of hydraulic lime in England in the late 19th century by Joseph Aspdin, and usually originates from limestone.

Joseph Aspdin (December 1778 – 20 March 1855) was an English cement manufacturer who obtained the patent for Portland cement on 21 October 1824.

It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum.

In the manufacture of Portland cement, clinker occurs as lumps or nodules, usually 3 mm to 25 mm in diameter, produced by sintering (fusing together without melting to the point of liquefaction) limestone and aluminosilicate materials such as clay during the cement kiln stage.

It was developed from other types of hydraulic lime in England in the late 19th century by Joseph Aspdin, and usually originates from limestone.

Limestone has numerous uses: as a building material, an essential component of concrete (Portland cement), as aggregate for the base of roads, as white pigment or filler in products such as toothpaste or paints, as a chemical feedstock for the production of lime, as a soil conditioner, or as a popular decorative addition to rock gardens.

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.

The most common binder since the early 20th century is Portland cement but the ancient binder lime mortar is still used in some new construction.

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.

In the latter nineteenth century, Portland cement was added with increasing frequency in an attempt to improve the durability of stucco.

However, his son William Aspdin is regarded as the inventor of "modern" Portland cement due to his developments in the 1840s.

William Aspdin (23 September 1815 – 11 April 1864) was an English cement manufacturer, and a pioneer of the Portland cement industry.

It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum.

Its name is derived from its similarity to Portland stone which was quarried on the Isle of Portland in Dorset, England.

Portland cement has nothing to do with Portland; it was so named due to its similar colour to Portland stone when mixed with lime and sand.

Isaac Charles Johnson further refined the production of 'meso-Portland cement' (middle stage of development), and claimed to be the real father of Portland cement.

Isaac Charles Johnson (28 January 1811 – 29 November 1911 ) was a British cement manufacturer, and a pioneer of the Portland cement industry.

In 1811, James Frost produced a cement he called British cement.

James Frost (1780?-1840?) was a British cement manufacturer who invented processes that led to the eventual development of Portland cement.

The powder can cause irritation or, with severe exposure, lung cancer, and can contain some hazardous components, such as crystalline silica and hexavalent chromium.

About 95% of the commercial use of silicon dioxide (sand) occurs in the construction industry, e.g. for the production of concrete (Portland cement concrete).

It was developed from other types of hydraulic lime in England in the late 19th century by Joseph Aspdin, and usually originates from limestone.

Artificial limes are more specifically identified as hydraulic lime (HL), as defined European Norm 459 (EN-459), "Consists of lime and other materials such as Portland cement, blast furnace slag, fly ash, limestone filler and other suitable materials."; formulated lime (FL) (EN-459) consists of "...mainly of hydrated lime and or NHL with added hydraulic and/or pozzolanic material. It is identical to HL but its composition must be declared on the CE marking."; pozzolanic hydraulic lime (PHL) (ASTM C-1707)is "very similar to HL or FL. Consists mainly of hydrated lime with one or more pozzolans with possible inclusion of inert filler. When Portland cement, even traces, is present (can be up to 20% of binder weight), it has to be labeled as 'PHLc'."

The key chemical reaction which defines Portland cement from other hydraulic limes occurs at these high temperatures (>1300 C) as belite (Ca 2 SiO 4 ) combines with calcium oxide (CaO) to form alite (Ca 3 SiO 5 ).

Belite is an industrial mineral important in Portland cement manufacture.

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, including trass and pozzolanas, relating to the planned construction of a lighthouse, now known as Smeaton's Tower.

Smeaton is important in the history, rediscovery of, and development of modern cement, identifying the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of 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.

Portland cement is the most common cementing agent in grout, but thermoset polymer matrix grouts based on thermosets such as urethanes and epoxies are also popular.

The key chemical reaction which defines Portland cement from other hydraulic limes occurs at these high temperatures (>1300 C) as belite (Ca 2 SiO 4 ) combines with calcium oxide (CaO) to form alite (Ca 3 SiO 5 ).

It is the major, and characteristic, mineral phase in Portland cement.

In 1859, John Grant of the Metropolitan Board of Works, set out requirements for cement to be used in the London sewer project.

The innovative use of Portland cement strengthened the tunnels, which were in good order 150 years later.

For special cements, such as low heat (LH) and sulfate resistant (SR) types, it is necessary to limit the amount of tricalcium aluminate (3 CaO·Al 2 O 3 ) formed.

It does not occur in nature, but is an important mineral phase in Portland cement.

Some of the materials used are clay, shale, sand, iron ore, bauxite, fly ash, and slag.

About 43% is recycled, often used as a pozzolan to produce hydraulic cement or hydraulic plaster and a replacement or partial replacement for Portland cement in concrete production.

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.

Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens over time—most frequently in the past a lime-based cement binder, such as lime putty, but sometimes with other hydraulic cements, such as a calcium aluminate cement or with Portland cement to form Portland cement concrete (for its visual resemblance to Portland stone).

The next development in the manufacture of Portland cement was the introduction of the rotary kiln, patented by Frederick Ransome in 1885 (U.K.) and 1886 (U.S.); which allowed a stronger, more homogeneous mixture and a continuous manufacturing process.

However, the stone fell out of use, in favour of Portland cement-based concrete, which could be more simply cast on-site.

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, including trass and pozzolanas, relating to the planned construction of a lighthouse, now known as Smeaton's Tower.

Mixed with lime and sand, or with Portland cement, it is extensively employed for hydraulic work, especially in the Netherlands; while the compact varieties have been used as a building material and as a fire-stone in ovens.

In 1811 Edgar Dobbs of Southwark patented a cement of the kind invented 7 years later by the French engineer Louis Vicat.

The material was popular but was superseded by Portland cement.

This is achieved in a cement mill.

The emergence of Portland cement in the 1840s made grinding considerably more difficult, because the clinker produced by the kiln is often as hard as the millstone material.