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59-679: Aberthaw Cement Works are cement works in the Vale of Glamorgan near the village of East Aberthaw in Wales . The Blue Lias limestone of Aberthaw was a source of hydraulic lime from early times, and it was made famous when it was selected by John Smeaton for the construction of the Eddystone Lighthouse but various records of Aberthaw Blue Lias limestone's processing are not consistent. Evidently, limestone pebbles from Aberthaw's coastline were transported inland for burning at other limekilns but much

118-596: 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),

177-405: A blend containing ground limestone (where a suffix L is present in the class names). White portland cement or white ordinary portland cement (WOPC) is similar to ordinary gray portland cement in all respects, except for its high degree of whiteness. Obtaining this colour requires high purity raw materials (low Fe 2 O 3 content), and some modification to the method of manufacture, among others

236-465: A construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Concrete can be used in the construction of structural elements like panels, beams, and street furniture , or may be cast- in situ for superstructures like roads and dams. These may be supplied with concrete mixed on site, or may be provided with ' ready-mixed ' concrete made at permanent mixing sites. Portland cement

295-400: A few weeks and this causes strength growth to stop. Five types of portland cements exist, with variations of the first three according to ASTM C150. Type I portland cement is known as common or general-purpose cement. It is generally assumed unless another type is specified. It is commonly used for general construction, especially when making precast, and precast-prestressed concrete that

354-487: A fusion temperature, which is about 1,450 °C (2,640 °F) for modern cements, to sinter the materials into clinker. The materials in cement clinker are alite, belite, tricalcium aluminate , and tetracalcium alumino ferrite. The aluminium, iron, and magnesium oxides are present as a flux allowing the calcium silicates to form at a lower temperature, and contribute little to the strength. For special cements, such as low heat (LH) and sulphate resistant (SR) types, it

413-514: A given project it is best to use cement from a single batch. Bags of cement routinely have health and safety warnings printed on them, because not only is cement highly alkaline , but the setting process is also exothermic . As a result, wet cement is strongly caustic and can easily cause severe skin burns if not promptly washed off with water. Similarly, dry cement powder in contact with mucous membranes can cause severe eye or respiratory irritation. The reaction of cement dust with moisture in

472-405: A higher kiln temperature required to sinter the clinker in the absence of ferric oxides acting as a flux in normal clinker. As Fe 2 O 3 contributes to decrease the melting point of the clinker (normally 1450 °C), the white cement requires a higher sintering temperature (around 1600 °C). Because of this, it is somewhat more expensive than the grey product. The main requirement is to have

531-527: A low iron content which should be less than 0.5 wt.% expressed as Fe 2 O 3 for white cement, and less than 0.9 wt.% for off-white cement. It also helps to have the iron oxide as ferrous oxide (FeO) which is obtained via slightly reducing conditions in the kiln, i.e., operating with zero excess oxygen at the kiln exit. This gives the clinker and cement a green tinge. Other metallic oxides such as Cr 2 O 3 (green), MnO (pink), TiO 2 (white), etc., in trace content, can also give colour tinges, so for

590-629: A mild heat. The European norm EN 197-1 defines five classes of common cement that comprise portland cement as a main constituent. These classes differ from the ASTM classes. * Constituents that are permitted in portland-composite cements are artificial pozzolans (blast furnace slag (in fact a latent hydraulic binder), silica fume, and fly ashes), or natural pozzolans (siliceous or siliceous aluminous materials such as volcanic ash glasses, calcined clays and shale). The Canadian standards describe six main classes of cement, four of which can also be supplied as

649-444: A production capacity of 120 tonnes per day each. The first consignment of cement left Aberthaw works by rail in 1914. A third wet kiln was ordered in 1913 and erected in 1916 during the first World War, and a fourth kiln was added and running by June 1958. This brought clinker capacity to 1200 tonnes per day. In 1967, Kiln 5 ( 51°23′51″N 3°23′38″W  /  51.39743°N 3.393965°W  / 51.39743; -3.393965 )

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708-459: A smoother final surface. They are often enhanced with polymers and/or latex . Structural grout is often used in reinforced masonry to fill voids in masonry housing reinforcing steel, securing the steel in place, and bonding it to the masonry. Nonshrinking grout is used beneath metal bearing plates to ensure a consistent bearing surface between the plate and its substrate, which adds stability and allows for higher load transfers. Portland cement

767-497: 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, including trass and pozzolanas , intended for the construction of a lighthouse, now known as Smeaton's Tower . In

826-412: A typical concrete sets in about 6 hours and develops a compressive strength of 8 MPa in 24 hours. The strength rises to 15 MPa at 3 days, 23 MPa at 1 week, 35 MPa at 4 weeks, and 41 MPa at 3 months. In principle, the strength continues to rise slowly as long as water is available for continued hydration, but concrete is usually allowed to dry out after

885-440: A very low (C 3 A) composition which accounts for its high sulphate resistance. The maximum content of (C 3 A) allowed is 5% for type V portland cement. Another limitation is that the (C 4 AF) + 2(C 3 A) composition cannot exceed 20%. This type is used in concrete to be exposed to alkali soil and ground water sulphates which react with (C 3 A) causing disruptive expansion. It is unavailable in many places, although its use

944-543: Is immediately dangerous to life and health . Portland cement manufacture can cause environmental impacts at all stages of the process. These include emissions of airborne pollution in the form of dust; gases; noise and vibration when operating machinery and during blasting in quarries; consumption of large quantities of fuel during manufacture; release of CO 2 from the raw materials during manufacture, and damage to countryside from quarrying. Equipment to reduce dust emissions during quarrying and manufacture of cement

1003-404: Is added to the clinker, and the mixture is finely ground to form the finished cement powder. This is achieved in a cement mill . The grinding process is controlled to obtain a powder with a broad particle size range , in which typically 15% by mass consists of particles below 5 μm diameter, and 5% of particles above 45 μm. The measure of fineness usually used is the ' specific surface area ', which

1062-409: Is also used in mortars (with sand and water only), for plasters and screeds , and in grouts (cement/water mixes squeezed into gaps to consolidate foundations, road-beds, etc.). When water is mixed with portland cement, the product sets in a few hours and hardens over a period of weeks. These processes can vary widely, depending upon the mix used and the conditions of curing of the product, but

1121-454: Is common in the western United States and Canada. As with type IV, type V portland cement has mainly been supplanted by the use of ordinary cement with added ground granulated blast furnace slag or tertiary blended cements containing slag and fly ash. Types Ia , IIa , and IIIa have the same composition as types I, II, and III. The only difference is that in Ia, IIa, and IIIa, an air-entraining agent

1180-429: Is delivered to end users either in bags, or as bulk powder blown from a pressure vehicle into the customer's silo. In industrial countries, 80% or more of cement is delivered in bulk. Cement sets when mixed with water by way of a complex series of chemical reactions still only partly understood. The different constituents slowly crystallise, and the interlocking of their crystals gives cement its strength. Carbon dioxide

1239-506: Is distinguished by its low viscosity and lack of lime (added to mortar for pliability); grout is thin so it flows readily into gaps, while mortar is thick enough to support not only its own weight, but also that of masonry placed above it. Grout varieties include tiling , flooring , resin , nonshrinking , structural, and thixotropic grouts. The use of enhancing admixtures increases the quality of cement-based materials and leads to greater uniformity of hardened properties. Tiling grout

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1298-411: Is generally known for its low heat of hydration. Its typical compound composition is: 28% (C 3 S), 49% (C 2 S), 4% (C 3 A), 12% (C 4 AF), 1.8% MgO, 1.9% (SO 3 ), 0.9% ignition loss, and 0.8% free CaO. The percentages of (C 2 S) and (C 4 AF) are relatively high and (C 3 S) and (C 3 A) are relatively low. A limitation on this type is that the maximum percentage of (C 3 A) is seven, and

1357-516: Is generally not stocked by manufacturers, but some might consider a large special order. This type of cement has not been made for many years, because portland-pozzolan cements and ground granulated blast furnace slag addition offer a cheaper and more reliable alternative. Type V is used where sulphate resistance is important. Its typical compound composition is: 38% (C 3 S), 43% (C 2 S), 4% (C 3 A), 9% (C 4 AF), 1.9% MgO, 1.8% (SO 3 ), 0.9% ignition loss, and 0.8% free CaO. This cement has

1416-464: Is grey, but white portland cement is also available. Its name is derived from its resemblance to Portland stone which is quarried on the Isle of Portland in Dorset , England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of "modern" portland cement due to his developments in the 1840s. The low cost and widespread availability of

1475-418: Is ground into the mix. The air-entrainment must meet the minimum and maximum optional specification found in the ASTM manual. These types are only available in the eastern United States and Canada, only on a limited basis. They are a poor approach to air-entrainment which improves resistance to freezing under low temperatures. Types II(MH) and II(MH)a have a similar composition as types II and IIa, but with

1534-452: Is heated to high temperature. The key chemical reaction distinguishing portland cement from other hydraulic limes occurs at these high temperatures (>1,300 °C (2,370 °F)) as belite (Ca 2 SiO 4 ) combines with calcium oxide (CaO) to form alite (Ca 3 SiO 5 ). Portland cement clinker is made by heating, in a cement kiln , a mixture of raw materials to a calcining temperature of above 600 °C (1,112 °F) and then

1593-471: Is in contact with soils and ground water, especially in the western United States due to the high sulphur content of the soils. Because of similar price to that of type I, type II is much used as a general purpose cement, and the majority of portland cement sold in North America meets this specification. Note: Cement meeting (among others) the specifications for types I and II has become commonly available on

1652-425: Is necessary to limit the amount of tricalcium aluminate (3 CaO·Al 2 O 3 ) formed. The major raw material for the clinker-making is usually limestone ( CaCO 3 ) mixed with a second material containing clay as source of alumino-silicate. Normally, an impure limestone which contains clay or SiO 2 is used. The CaCO 3 content of these limestones can be as low as 80%. Secondary raw materials (materials in

1711-473: Is not to be in contact with soils or ground water. The typical compound compositions of this type are: 55% (C 3 S), 19% (C 2 S), 10% (C 3 A), 7% (C 4 AF), 2.8% MgO, 2.9% (SO 3 ), 1.0% ignition loss , and 1.0% free CaO (utilizing cement chemist notation ). A limitation on the composition is that the (C 3 A) shall not exceed 15%. Type II provides moderate sulphate resistance, and gives off less heat during hydration. This type of cement costs about

1770-401: Is often used to fill the spaces between tiles or mosaics and to secure tile to its base. Although ungrouted mosaics do exist, most have grout between the tesserae . Tiling grout is also cement-based, and is produced in sanded and unsanded varieties, which affects the strength, size, and appearance of the grout. The sanded variety contains finely ground silica sand; unsanded is finer and produces

1829-620: Is on record that geologically, the limestone seam at Aberthaw runs under the Bristol Channel and is also present at Watchet. The Aberthaw and Bristol Channel Portland Cement Company was established in 1912 by the Beynon family. The site at Aberthaw was chosen as it was near the necessary raw material, limestone and coal from the South Wales coalfield which was needed to heat the kilns . The works started in 1914 with two small wet process kilns with

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1888-423: Is slowly absorbed to convert the portlandite (Ca(OH) 2 ) into insoluble calcium carbonate . After the initial setting, immersion in warm water will speed up setting. Gypsum is added as an inhibitor to prevent flash (or quick) setting. The most common use for portland cement is in the production of concrete. Concrete is a composite material consisting of aggregate ( gravel and sand ), cement, and water. As

1947-406: Is that the six-month strength of type III is the same or slightly less than that of types I and II. Therefore, the long-term strength is sacrificed. It is usually used for precast concrete manufacture, where high one-day strength allows fast turnover of molds. It may also be used in emergency construction and repairs, and construction of machine bases and gate installations. Type IV portland cement

2006-429: Is the most common cementing agent in grout, but thermoset polymer matrix grouts based on thermosets such as urethanes and epoxies are also popular. Portland cement-based grouts include different varieties depending on the particle size of the ground clinker used to make the cement, with a standard size around 15 microns , microfine from 6–10 microns, and ultrafine below 5 microns. Finer particle sizes let

2065-522: Is the total particle surface area of a unit mass of cement. The rate of initial reaction (up to 24 hours) of the cement on addition of water is directly proportional to the specific surface area. Typical values are 320–380 m ·kg for general purpose cements, and 450–650 m ·kg for 'rapid hardening' cements. The cement is conveyed by belt or powder pump to a silo for storage. Cement plants normally have sufficient silo space for one to 20 weeks of production, depending upon local demand cycles. The cement

2124-402: Is widely used, and equipment to trap and separate exhaust gases are coming into increased use. Environmental protection also includes the re-integration of quarries into the countryside after they have been closed down by returning them to nature or re-cultivating them. Grout Although both grout and its close relative mortar are applied as a thick suspension and harden over time, grout

2183-469: The German Standard , issued in 1909). Clinkers make up more than 90% of the cement, along with a limited amount of calcium sulphate (CaSO 4 , which controls the set time), and up to 5% minor constituents (fillers) as allowed by various standards. Clinkers are nodules (diameters, 0.2–1.0 inch [5.1–25.4 millimetres]) of a sintered material that is produced when a raw mixture of predetermined composition

2242-467: The London sewer project . This became a specification for portland cement. 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. The Hoffmann "endless" kiln which was said to give "perfect control over combustion"

2301-544: The Occupational Safety and Health Administration (OSHA) has set the legal limit ( permissible exposure limit ) for portland cement exposure in the workplace as 50 mppcf (million particles per cubic foot) over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m total exposure and 5 mg/m respiratory exposure over an 8-hour workday. At levels of 5000 mg/m , portland cement

2360-653: The first portland cement was produced in the Coplay Cement Company Kilns under the direction of David O. Saylor in Coplay, Pennsylvania . By the early 20th century, American-made portland cement had displaced most of the imported portland cement. ASTM C150 defines portland cement as: hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by pulverizing clinkers which consist essentially of hydraulic calcium silicates, usually containing one or more of

2419-581: The forms of calcium sulphate as an inter ground addition. The European Standard EN 197-1 uses the following definition: Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates , (3 CaO·SiO 2 , and 2 CaO·SiO 2 ) , the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO 2 shall not be less than 2.0. The magnesium oxide content ( MgO ) shall not exceed 5.0% by mass. (The last two requirements were already set out in

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2478-426: The general purpose clinker is usually used, ground to a specific surface area typically 50–80% higher. The gypsum level may also be increased a small amount. This gives the concrete using this type of cement a three-day compressive strength equal to the seven-day compressive strength of types I and II. Its seven-day compressive strength is almost equal to 28-day compressive strengths of types I and II. The only downside

2537-415: The grout penetrate more deeply into a fissure. Because these grouts depend on the presence of sand for their basic strength, they are often somewhat gritty when finally cured and hardened. From the different types of grout, a suitable one has to be chosen depending on the load. For example, a load up to 7.5 tons can be expected for a garage access [two-component pavement joint mortar (traffic load)], whereas

2596-518: The kind invented 7 years later by the French engineer Louis Vicat . Vicat's cement is an artificial hydraulic lime , and is considered the "principal forerunner" of portland cement. The name portland cement is recorded in a directory published in 1823 being associated with a William Lockwood and possibly others. In his 1824 cement patent, Joseph Aspdin called his invention "portland cement" because of its resemblance to Portland stone . Aspdin's cement

2655-410: The largest cement maker in the world. Cement from the site is carried to destinations by Road and Rail (rail services being provided by Freightliner heavy haul and Colas Rail over the Vale of Glamorgan Line ). In July 2020, it was observed that Aberthaw cement in bulk was being shipped in large consignments by PCA rail tank wagons equipped for pressure unloading at destination, thus considerably reducing

2714-410: 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 1850s. In 1811, James Frost produced a cement he called British cement. James Frost is reported to have erected a manufactory for making of an artificial cement in 1826. In 1811 Edgar Dobbs of Southwark patented a cement of

2773-496: The limestone, shales , and other naturally occurring materials used in portland cement make it a relatively cheap building material. Its most common use is in the production of concrete, a composite material consisting of aggregate (gravel and sand), cement, and water. 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 ,

2832-417: The maximum percentage of (C 3 S) is thirty-five. This causes the heat given off by the hydration reaction to develop at a slower rate. Consequently, the strength of the concrete develops slowly. After one or two years the strength is higher than the other types after full curing. This cement is used for very large concrete structures, such as dams, which have a low surface to volume ratio. This type of cement

2891-407: The number of bulk cement road tankers on the highways. Watercolour artist Thomas Frederick Worrall worked for a few years at the cement works from when it was first opened. 51°23′51″N 3°23′35″W  /  51.39750°N 3.39306°W  / 51.39750; -3.39306 Portland cement Portland cement is the most common type of cement in general use around the world as

2950-423: The raw mix other than limestone) depend on the purity of the limestone. Some of the materials used are clay , shale , sand , iron ore , bauxite , fly ash , and slag . When a cement kiln is fired by coal, the ash of the coal acts as a secondary raw material. To achieve the desired setting qualities in the finished product, a quantity (2–8%, but typically 5%) of calcium sulphate (usually gypsum or anhydrite )

3009-416: The same as type I. Its typical compound composition is: 51% (C 3 S), 24% (C 2 S), 6% (C 3 A), 11% (C 4 AF), 2.9% MgO, 2.5% (SO 3 ), 0.8% ignition loss, and 1.0% free CaO. A limitation on the composition is that the (C 3 A) shall not exceed 8%, which reduces its vulnerability to sulphates. This type is for general construction exposed to moderate sulphate attack, and is meant for use when concrete

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3068-508: The sinuses and lungs can also cause a chemical burn, as well as headaches, fatigue, and lung cancer. The production of comparatively low-alkalinity cements (pH<11) is an area of ongoing investigation. In Scandinavia , France, and the United Kingdom, the level of chromium(VI) , which is considered to be toxic and a major skin irritant, may not exceed 2 parts per million (ppm). In the US,

3127-441: The two sites at Aberthaw and Rhoose in 1983. In 1987, Rhoose Works closed and was later completely demolished. The former Rhoose works kiln firing fuel had gone from coal to oil, then gas. The same applied to Aberthaw but reversion to coal came in 1979 but Aberthaw plant was authorised to burn whole tyres as fuel from 2013, with no impact on the environment. Lafarge Cement UK bought Blue Circle industries PLC in 2001, creating

3186-406: The world market. Type III has relatively high early strength. Its typical compound composition is: 57% (C 3 S), 19% (C 2 S), 10% (C 3 A), 7% (C 4 AF), 3.0% MgO, 3.1% (SO 3 ), 0.9% ignition loss, and 1.3% free CaO. This cement is similar to type I, but ground finer. Some manufacturers make a separate clinker with higher C 3 S and/or C 3 A content, but this is increasingly rare, and

3245-438: Was installed. This was a much more efficient dry process kiln. The wet process kilns were decommissioned in 1974, and Kiln 6 - also a dry kiln - ( 51°23′51″N 3°23′40″W  /  51.397507°N 3.394326°W  / 51.397507; -3.394326 ) was started in 1975. Kiln 6 remains in operation today. In 1919 the company took over the nearby Aberthaw and Rhoose Point Portland and Lime Company. Blue Circle bought

3304-475: Was involved in cement making. William Aspdin made what could be called "meso-portland cement" (a mix of portland cement and hydraulic lime). 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. In 1859, John Grant of the Metropolitan Board of Works, set out requirements for cement to be used in

3363-481: Was nothing like modern portland cement, but a first step in the development of modern portland cement, and has been called a "proto-portland cement". William Aspdin had left his father's company, to form his own cement manufactury. In the 1840s William Aspdin, apparently accidentally, produced calcium silicates which are a middle step in the development of portland cement. In 1848, William Aspdin further improved his cement. Then, in 1853, he moved to Germany, where he

3422-533: Was shipped across the Bristol Channel from the Port of Aberthaw, for burning at Three Kilns, Cleeve Hill, near Watchet, Somerset. One historical account states that John Smeaton used Watchet's burned lime which was shipped to Millbay, Plymouth for his Eddystone lighthouse construction in 1756. It was not until 1888 that a (pebble) limeworks and kilns, were constructed alongside Pleasant Harbour, East Aberthaw but that works, which had become rail-served by 1892, closed in 1926. It

3481-602: Was tested in 1860 and shown to produce a superior grade of cement. This cement was made at the Portland Cementfabrik Stern at Stettin , which was the first to use a Hoffmann kiln. The Association of German Cement Manufacturers issued a standard on portland cement in 1878. Portland cement had been imported into the United States from Germany and England , and in the 1870s and 1880s, it was being produced by Eagle Portland cement near Kalamazoo, Michigan. In 1875,

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