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55-450: Ambuja Cements Limited , formerly known as Gujarat Ambuja Cement Limited (GACL) , is a major Indian cement producing company. The Group markets cement and clinker for both domestic and export markets. The company had entered into a strategic partnership with Holcim, the second-largest cement manufacturer in the world from 2006. Holcim had, in January, bought a 14.8 percent promoters' stake in

110-554: A chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble. This allows setting in wet conditions or under water and further protects the hardened material from chemical attack. The chemical process for hydraulic cement was found by ancient Romans who used volcanic ash ( pozzolana ) with added lime (calcium oxide). Non-hydraulic cement (less common) does not set in wet conditions or under water. Rather, it sets as it dries and reacts with carbon dioxide in

165-546: A mortar made of sand and roughly burnt gypsum (CaSO 4 · 2H 2 O), which is plaster of Paris, which often contained calcium carbonate (CaCO 3 ), Lime (calcium oxide) was used on Crete and by the Ancient Greeks . There is evidence that the Minoans of Crete used crushed potsherds as an artificial pozzolan for hydraulic cement. Nobody knows who first discovered that a combination of hydrated non-hydraulic lime and

220-420: A controlled bond with masonry blocks. Expansive cements contain, in addition to Portland clinker, expansive clinkers (usually sulfoaluminate clinkers), and are designed to offset the effects of drying shrinkage normally encountered in hydraulic cements. This cement can make concrete for floor slabs (up to 60 m square) without contraction joints. Hydration reaction Any unsaturated organic compound

275-432: A fine powder. This product, made into a mortar with sand, set in 5–15 minutes. The success of "Roman cement" led other manufacturers to develop rival products by burning artificial hydraulic lime cements of clay and chalk . Roman cement quickly became popular but was largely replaced by Portland cement in the 1850s. Apparently unaware of Smeaton's work, the same principle was identified by Frenchman Louis Vicat in

330-432: A form of hydraulic cement, is by far the most common type of cement in general use around the world. This cement is made by heating limestone (calcium carbonate) with other materials (such as clay ) to 1,450 °C (2,640 °F) in a kiln , in a process known as calcination that liberates a molecule of carbon dioxide from the calcium carbonate to form calcium oxide , or quicklime, which then chemically combines with

385-669: A half-century. Technologies of waste cementation have been developed and deployed at industrial scale in many countries. Cementitious wasteforms require a careful selection and design process adapted to each specific type of waste to satisfy the strict waste acceptance criteria for long-term storage and disposal. Modern development of hydraulic cement began with the start of the Industrial Revolution (around 1800), driven by three main needs: Modern cements are often Portland cement or Portland cement blends, but other cement blends are used in some industrial settings. Portland cement,

440-787: A market for use in concrete. The use of concrete in construction grew rapidly from 1850 onward, and was soon the dominant use for cements. Thus Portland cement began its predominant role. Isaac Charles Johnson further refined the production of meso-Portland cement (middle stage of development) and claimed he was the real father of Portland cement. Setting time and "early strength" are important characteristics of cements. Hydraulic limes, "natural" cements, and "artificial" cements all rely on their belite (2 CaO · SiO 2 , abbreviated as C 2 S) content for strength development. Belite develops strength slowly. Because they were burned at temperatures below 1,250 °C (2,280 °F), they contained no alite (3 CaO · SiO 2 , abbreviated as C 3 S), which

495-413: A month for Rosendale cement made it unpopular for constructing highways and bridges, and many states and construction firms turned to Portland cement. Because of the switch to Portland cement, by the end of the 1920s only one of the 15 Rosendale cement companies had survived. But in the early 1930s, builders discovered that, while Portland cement set faster, it was not as durable, especially for highways—to

550-682: A pozzolan produces a hydraulic mixture (see also: Pozzolanic reaction ), but such concrete was used by the Greeks, specifically the Ancient Macedonians , and three centuries later on a large scale by Roman engineers . There is... a kind of powder which from natural causes produces astonishing results. It is found in the neighborhood of Baiae and in the country belonging to the towns round about Mount Vesuvius . This substance when mixed with lime and rubble not only lends strength to buildings of other kinds but even when piers of it are constructed in

605-726: A very advanced civilisation in El Tajin near Mexico City, in Mexico. A detailed study of the composition of the aggregate and binder show that the aggregate was pumice and the binder was a pozzolanic cement made with volcanic ash and lime. Any preservation of this knowledge in literature from the Middle Ages is unknown, but medieval masons and some military engineers actively used hydraulic cement in structures such as canals , fortresses, harbors , and shipbuilding facilities . A mixture of lime mortar and aggregate with brick or stone facing material

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660-483: Is Aldehydes and to some extent even ketones, hydrate to geminal diols . The reaction is especially dominant for formaldehyde, which, in the presence of water, exists significantly as dihydroxymethane. Conceptually similar reactions include hydroamination and hydroalkoxylation , which involve adding amines and alcohols to alkenes. Nitriles are susceptible to hydration to amides: RCN + H 2 O → RC(O)NH 2 This reaction requires catalysts. Enzymes are used for

715-422: Is hydraulic cement , which hardens by hydration of the clinker minerals when water is added. Hydraulic cements (such as Portland cement) are made of a mixture of silicates and oxides, the four main mineral phases of the clinker, abbreviated in the cement chemist notation , being: The silicates are responsible for the cement's mechanical properties — the tricalcium aluminate and brownmillerite are essential for

770-512: Is pozzolanic , so that ultimate strength is maintained. Because fly ash addition allows a lower concrete water content, early strength can also be maintained. Where good quality cheap fly ash is available, this can be an economic alternative to ordinary Portland cement. Portland pozzolan cement includes fly ash cement, since fly ash is a pozzolan , but also includes cements made from other natural or artificial pozzolans. In countries where volcanic ashes are available (e.g., Italy, Chile, Mexico,

825-403: Is a binder , a chemical substance used for construction that sets , hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate ) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel , produces concrete . Concrete is the most widely used material in existence and

880-520: Is a major emitter of global carbon dioxide emissions . The lime reacts with silicon dioxide to produce dicalcium silicate and tricalcium silicate. The lime also reacts with aluminium oxide to form tricalcium aluminate. In the last step, calcium oxide, aluminium oxide, and ferric oxide react together to form brownmillerite. A less common form of cement is non-hydraulic cement , such as slaked lime ( calcium oxide mixed with water), which hardens by carbonation in contact with carbon dioxide , which

935-569: Is about 4.4 billion tonnes per year (2021, estimation), of which about half is made in China, followed by India and Vietnam. The cement production process is responsible for nearly 8% (2018) of global CO 2 emissions, which includes heating raw materials in a cement kiln by fuel combustion and release of CO 2 stored in the calcium carbonate (calcination process). Its hydrated products, such as concrete, gradually reabsorb atmospheric CO 2 (carbonation process), compensating for approximately 30% of

990-424: Is behind only water as the planet's most-consumed resource. Cements used in construction are usually inorganic , often lime - or calcium silicate -based, and are either hydraulic or less commonly non-hydraulic , depending on the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster ). Hydraulic cements (e.g., Portland cement ) set and become adhesive through

1045-467: Is called the "indirect process". In the "direct process," the acid protonates the alkene, and water reacts with this incipient carbocation to give the alcohol. The direct process is more popular because it is simpler. The acid catalysts include phosphoric acid and several solid acids . Here an example reaction mechanism of the hydration of 1-methylcyclohexene to 1-methylcyclohexanol: Many alternative routes are available for producing alcohols, including

1100-417: Is completely evaporated (this process is technically called setting ), the carbonation starts: This reaction is slow, because the partial pressure of carbon dioxide in the air is low (~ 0.4 millibar). The carbonation reaction requires that the dry cement be exposed to air, so the slaked lime is a non-hydraulic cement and cannot be used under water. This process is called the lime cycle . Perhaps

1155-555: Is constantly fed into a rotary kiln, it allowed a continuous manufacturing process to replace lower capacity batch production processes. Calcium aluminate cements were patented in 1908 in France by Jules Bied for better resistance to sulfates. Also in 1908, Thomas Edison experimented with pre-cast concrete in houses in Union, N.J. In the US, after World War One, the long curing time of at least

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1210-493: Is highly exothermic. In the first step, the alkene acts as a nucleophile and attacks the proton, following Markovnikov's rule . In the second step an H 2 O molecule bonds to the other, more highly substituted carbon. The oxygen atom at this point has three bonds and carries a positive charge (i.e., the molecule is an oxonium ). Another water molecule comes along and takes up the extra proton. This reaction tends to yield many undesirable side products, (for example diethyl ether in

1265-667: Is more usually added to Portland cement at the concrete mixer. Masonry cements are used for preparing bricklaying mortars and stuccos , and must not be used in concrete. They are usually complex proprietary formulations containing Portland clinker and a number of other ingredients that may include limestone, hydrated lime, air entrainers, retarders, waterproofers, and coloring agents. They are formulated to yield workable mortars that allow rapid and consistent masonry work. Subtle variations of masonry cement in North America are plastic cements and stucco cements. These are designed to produce

1320-403: Is present in the air (~ 412 vol. ppm ≃ 0.04 vol. %). First calcium oxide (lime) is produced from calcium carbonate ( limestone or chalk ) by calcination at temperatures above 825 °C (1,517 °F) for about 10 hours at atmospheric pressure : The calcium oxide is then spent (slaked) by mixing it with water to make slaked lime ( calcium hydroxide ): Once the excess water

1375-483: Is responsible for early strength in modern cements. The first cement to consistently contain alite was made by William Aspdin in the early 1840s: This was what we call today "modern" Portland cement. Because of the air of mystery with which William Aspdin surrounded his product, others ( e.g., Vicat and Johnson) have claimed precedence in this invention, but recent analysis of both his concrete and raw cement have shown that William Aspdin's product made at Northfleet , Kent

1430-417: Is susceptible to hydration. Several million tons of ethylene glycol are produced annually by the hydration of oxirane , a cyclic compound also known as ethylene oxide : Acid catalysts are typically used. The general chemical equation for the hydration of alkenes is the following: A hydroxyl group (OH ) attaches to one carbon of the double bond, and a proton (H ) adds to the other. The reaction

1485-438: Is to make concrete. Portland cement may be grey or white . Portland cement blends are often available as inter-ground mixtures from cement producers, but similar formulations are often also mixed from the ground components at the concrete mixing plant. Portland blast-furnace slag cement , or blast furnace cement (ASTM C595 and EN 197-1 nomenclature respectively), contains up to 95% ground granulated blast furnace slag , with

1540-474: The Isle of Portland , Dorset, England. However, Aspdins' cement was nothing like modern Portland cement but was a first step in its development, called a proto-Portland cement . Joseph Aspdins' son William Aspdin had left his father's company and in his cement manufacturing apparently accidentally produced calcium silicates in the 1840s, a middle step in the development of Portland cement. William Aspdin's innovation

1595-534: The hydroboration–oxidation reaction , the oxymercuration–reduction reaction , the Mukaiyama hydration , the reduction of ketones and aldehydes and as a biological method fermentation . Acetylene hydrates to give acetaldehyde: The process typically relies on mercury catalysts and has been discontinued in the West but is still practiced in China. The Hg center binds to a C≡C bond, which is then attacked by water. The reaction

1650-517: The Art to Prepare a Good Mortar published in St. Petersburg . A few years later in 1825, he published another book, which described various methods of making cement and concrete, and the benefits of cement in the construction of buildings and embankments. Portland cement , the most common type of cement in general use around the world as a basic ingredient of concrete, mortar , stucco , and non-speciality grout ,

1705-722: The GACL for ₹ 2,140 crore . From 2010 to 2022, Holcim held a 61.62% controlling stake in Ambuja Cements. On 14 April 2022, Holcim announced that it would exit from the Indian market after 17 years of operations as part of a strategy to focus on core markets, and listed its stakes in Ambuja Cements and ACC for sale. On May 15, 2022, Adani Group acquired Holcim's stake in Ambuja Cements and ACC for US$ 10.5 billion. In October 2024, Ambuja Cement acquired CK Birla's Orient Cement at an approximate value of INR 8,100 Crore. Cement A cement

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1760-526: The New York Commissioner of Highways to construct an experimental section of highway near New Paltz, New York , using one sack of Rosendale to six sacks of Portland cement. It was a success, and for decades the Rosendale-Portland cement blend was used in concrete highway and concrete bridge construction. Cementitious materials have been used as a nuclear waste immobilizing matrix for more than

1815-457: The Philippines), these cements are often the most common form in use. The maximum replacement ratios are generally defined as for Portland-fly ash cement. Portland silica fume cement. Addition of silica fume can yield exceptionally high strengths, and cements containing 5–20% silica fume are occasionally produced, with 10% being the maximum allowed addition under EN 197–1. However, silica fume

1870-603: The absence of pozzolanic ash, the Romans used powdered brick or pottery as a substitute and they may have used crushed tiles for this purpose before discovering natural sources near Rome. The huge dome of the Pantheon in Rome and the massive Baths of Caracalla are examples of ancient structures made from these concretes, many of which still stand. The vast system of Roman aqueducts also made extensive use of hydraulic cement. Roman concrete

1925-623: The air. It is resistant to attack by chemicals after setting. The word "cement" can be traced back to the Ancient Roman term opus caementicium , used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder , were later referred to as cementum , cimentum , cäment , and cement . In modern times, organic polymers are sometimes used as cements in concrete. World production of cement

1980-516: The available hydraulic limes, visiting their production sites, and noted that the "hydraulicity" of the lime was directly related to the clay content of the limestone used to make it. Smeaton was a civil engineer by profession, and took the idea no further. In the South Atlantic seaboard of the United States, tabby relying on the oyster-shell middens of earlier Native American populations

2035-420: The development of new cements. Most famous was Parker's " Roman cement ". This was developed by James Parker in the 1780s, and finally patented in 1796. It was, in fact, nothing like material used by the Romans, but was a "natural cement" made by burning septaria – nodules that are found in certain clay deposits, and that contain both clay minerals and calcium carbonate . The burnt nodules were ground to

2090-607: The earliest known occurrence of cement is from twelve million years ago. A deposit of cement was formed after an occurrence of oil shale located adjacent to a bed of limestone burned by natural causes. These ancient deposits were investigated in the 1960s and 1970s. Cement, chemically speaking, is a product that includes lime as the primary binding ingredient, but is far from the first material used for cementation. The Babylonians and Assyrians used bitumen (asphalt or pitch ) to bind together burnt brick or alabaster slabs. In Ancient Egypt , stone blocks were cemented together with

2145-461: The first decade of the nineteenth century. Vicat went on to devise a method of combining chalk and clay into an intimate mixture, and, burning this, produced an "artificial cement" in 1817 considered the "principal forerunner" of Portland cement and "...Edgar Dobbs of Southwark patented a cement of this kind in 1811." In Russia, Egor Cheliev created a new binder by mixing lime and clay. His results were published in 1822 in his book A Treatise on

2200-402: The formation of the liquid phase during the sintering ( firing ) process of clinker at high temperature in the kiln . The chemistry of these reactions is not completely clear and is still the object of research. First, the limestone (calcium carbonate) is burned to remove its carbon, producing lime (calcium oxide) in what is known as a calcination reaction. This single chemical reaction

2255-426: The initial CO 2 emissions. Cement materials can be classified into two distinct categories: hydraulic cements and non-hydraulic cements according to their respective setting and hardening mechanisms. Hydraulic cement setting and hardening involves hydration reactions and therefore requires water, while non-hydraulic cements only react with a gas and can directly set under air. By far the most common type of cement

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2310-404: The low pH (8.5–9.5) of its pore water) limited its use as reinforced concrete for building construction. The next development in the manufacture of Portland cement was the introduction of the rotary kiln . It produced a clinker mixture that was both stronger, because more alite (C 3 S) is formed at the higher temperature it achieved (1450 °C), and more homogeneous. Because raw material

2365-465: The other materials in the mix to form calcium silicates and other cementitious compounds. The resulting hard substance, called 'clinker', is then ground with a small amount of gypsum ( CaSO 4 ·2H 2 O ) into a powder to make ordinary Portland cement , the most commonly used type of cement (often referred to as OPC). Portland cement is a basic ingredient of concrete , mortar , and most non-specialty grout . The most common use for Portland cement

2420-467: The point that some states stopped building highways and roads with cement. Bertrain H. Wait, an engineer whose company had helped construct the New York City's Catskill Aqueduct , was impressed with the durability of Rosendale cement, and came up with a blend of both Rosendale and Portland cements that had the good attributes of both. It was highly durable and had a much faster setting time. Wait convinced

2475-434: The process of creating ethanol ) and in its simple form described here is not considered very useful for the production of alcohol. Two approaches are taken. Traditionally the alkene is treated with sulfuric acid to give alkyl sulphate esters . In the case of ethanol production, this step can be written: Subsequently, this sulphate ester is hydrolyzed to regenerate sulphuric acid and release ethanol: This two step route

2530-447: The rest Portland clinker and a little gypsum. All compositions produce high ultimate strength, but as slag content is increased, early strength is reduced, while sulfate resistance increases and heat evolution diminishes. Used as an economic alternative to Portland sulfate-resisting and low-heat cements. Portland-fly ash cement contains up to 40% fly ash under ASTM standards (ASTM C595), or 35% under EN standards (EN 197–1). The fly ash

2585-407: The sea, they set hard underwater. The Greeks used volcanic tuff from the island of Thera as their pozzolan and the Romans used crushed volcanic ash (activated aluminium silicates ) with lime. This mixture could set under water, increasing its resistance to corrosion like rust. The material was called pozzolana from the town of Pozzuoli , west of Naples where volcanic ash was extracted. In

2640-444: Was a true alite-based cement. However, Aspdin's methods were "rule-of-thumb": Vicat is responsible for establishing the chemical basis of these cements, and Johnson established the importance of sintering the mix in the kiln . In the US the first large-scale use of cement was Rosendale cement , a natural cement mined from a massive deposit of dolomite discovered in the early 19th century near Rosendale, New York . Rosendale cement

2695-479: Was counterintuitive for manufacturers of "artificial cements", because they required more lime in the mix (a problem for his father), a much higher kiln temperature (and therefore more fuel), and the resulting clinker was very hard and rapidly wore down the millstones , which were the only available grinding technology of the time. Manufacturing costs were therefore considerably higher, but the product set reasonably slowly and developed strength quickly, thus opening up

2750-468: Was developed in England in the mid 19th century, and usually originates from limestone . James Frost produced what he called "British cement" in a similar manner around the same time, but did not obtain a patent until 1822. In 1824, Joseph Aspdin patented a similar material, which he called Portland cement , because the render made from it was in color similar to the prestigious Portland stone quarried on

2805-494: Was extremely popular for the foundation of buildings ( e.g. , Statue of Liberty , Capitol Building , Brooklyn Bridge ) and lining water pipes. Sorel cement , or magnesia-based cement, was patented in 1867 by the Frenchman Stanislas Sorel . It was stronger than Portland cement but its poor water resistance (leaching) and corrosive properties ( pitting corrosion due to the presence of leachable chloride anions and

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2860-622: Was formalized by French and British engineers in the 18th century. John Smeaton made an important contribution to the development of cements while planning the construction of the third Eddystone Lighthouse (1755–59) in the English Channel now known as Smeaton's Tower . He needed a hydraulic mortar that would set and develop some strength in the twelve-hour period between successive high tides . He performed experiments with combinations of different limestones and additives including trass and pozzolanas and did exhaustive market research on

2915-405: Was rarely used on the outside of buildings. The normal technique was to use brick facing material as the formwork for an infill of mortar mixed with an aggregate of broken pieces of stone, brick, potsherds , recycled chunks of concrete, or other building rubble. Lightweight concrete was designed and used for the construction of structural elements by the pre-Columbian builders who lived in

2970-407: Was used in house construction from the 1730s to the 1860s. In Britain particularly, good quality building stone became ever more expensive during a period of rapid growth, and it became a common practice to construct prestige buildings from the new industrial bricks, and to finish them with a stucco to imitate stone. Hydraulic limes were favored for this, but the need for a fast set time encouraged

3025-673: Was used in the Eastern Roman Empire as well as in the West into the Gothic period . The German Rhineland continued to use hydraulic mortar throughout the Middle Ages, having local pozzolana deposits called trass . Tabby is a building material made from oyster shell lime, sand, and whole oyster shells to form a concrete. The Spanish introduced it to the Americas in the sixteenth century. The technical knowledge for making hydraulic cement

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