Construction materials calcium

Calcium oxide is used as a flux in steel production and in building and construction materials. Calcium oxide is also important in paper manufacture, sewage treatment, agriculture, leather tanning, and glass manufacturing. 

Three other compounds of s-block elements—calcium oxide (CaO, known as lime ), sodium hydroxide (NaOH), and sodium carbonate (Na2 CO3)—are among the top 15 industrial chemicals in annual production. Lime is perennially in the top 10 because it is the key ingredient in construction materials such as concrete, cement, mortar, and plaster. Two other compounds, calcium chloride (CaCl2 ) and sodium sulfate (Na2 SO4 ), rank just below the top 50 in industrial importance. 

Calcium oxide is one of the most important industrial chemicals. It is used in the manufacture of building and construction materials, including bricks, mortar, stucco and plaster. It also is used as a flux in the manufacture of steel. 

The abundance of limestone deposits throughout the world has resulted in the use of calcium carbonate as a primary building material since antiquity. The ancient pyramids and the Sphinx in Egypt were made almost exclusively with limestone 5,000 years ago. Most limestone is used today as construction material. One estimate is that the United States used a billion tons of crushed limestone for roads, dams, fill, buildings, and various other construction uses in 2005. 

Self-Test 14.2B Explain why calcium compounds are such good construction materials. 

Portland cement, a complex mixture of calcium silicates, aluminates, and ferrates, is one of the world s most important construction materials, with annual worldwide production in excess of lO kg. When mixed with water and sand, it changes by slow hydration to concrete. Water and hydroxide link the other components into larger crystals with great strength. 

Large-quantities of quicklime are used in the manufacture of sand-lime bricks and aerated concrete blocks. These are construction materials which are manufactured from lime-containing and silicate-containing raw materials and whose strength is due to the hydrothermal reaction of the raw materials to calcium silicates. 

Calcium sulfate dihydrate gypsum), CaS04-2 H2O, is used in construction materials. 

Petroleum coke, obtained by subjecting the distillation bottoms to pyrolitic polymerization and thermal decomposition in a delayed or fluid coker, is used in the manufacture of calcium and silicon carbides, electrodes for aluminum manufacturing, and graphite. It also finds use as a utility fuel and as a construction material in foundry and blast furnaces. 

As a rule, however, the corrosiveness of a natural water is determined by the carbonic acid. Free, dissolved carbonic acid which can exist in the water as physically dissolved CO2 but also as H2CO3, can give the water corrosive properties towards metals and constructional materials (e.g. cement). From the point of view of development, waters are described as lime-corroding if they can dissolve calcium carbonate and thus also attack such constructional materials and corrode metals. If a water is supersaturated with calcium carbonate, it can be described as lime-precipitating and the formation of coatings in pipelines must be evaluated positively and... 

As diverse research studies have reported in the last 30 years there is no doubt about the destructive effect of the gypsum, although the deterioration mechanisms proposed are diverse and agreement does not exist. This is partially due to the different effect of the calcium sulphate salts on the constructive materials (stone, brick or mortars). Some of such materials can be damaged by physical and chemical action, as they are considered as reactive (e.g. limestone and most mortars), while others just show a physic interaction due to salt crystallization in the porous material matrix. This aspect will be considered further on another section. 

Naik, T. R., Singh, S. S. (1995) Use of high-calcium fly ash in cement-based construction materials, in Froc. 5th CANMET/ACI Int. Conf. on Fly Ash, Silica Fume, Slag and Natural Fozzolans in Concrete. Milwaukee WI Suppl. Papers pp. 1 4. 

Calcium oxide is an industrial chemical used in making construction materials such as bricks, mortar, plaster, and stucco. It is also used in manufacturing sodium carbonate, one of the most widely used of all chemicals, and in manufacturing steel, magnesium, and aluminum. 

De Muynck W, De Belie N, Verstraete W (2010) Microbial carbonate precipitation in construction materials a review. Ecol Eng 36(2) 118-136. doi 10.1016/j.ecoleng.2009.02.006 De Muynck W, Leuridan S, Van Loo D, Verbeken K, Cnudde V, De Behe N, Verstraete W (2011) Influence of pore structure on the effectiveness of a biogenic carbonate surface treatment for limestone conservation. Appl Environ Microbiol 77(19) 6808-6820. doi 10.1128/AEM.00219-ll Del Monte M, Sabbioni C, Zappia G (1987) The origin of calcium oxalates on historical buildings, monuments and natural outcrops. Sci Total Environ 67 17-39. doiilO. 1016/0048-9697(87)90063-5... 

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