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If nothing is done to control and slow down the C 3 A hydration rate, concrete can be easily subjected to flash setting, especially if the ambient temperature is elevated during the summer. This is why a small addition of 2 – 5 wt. % of gypsum ( CaSO 4 ·2H 2 O : solubility ~ 1 – 2 g/L water ) is done to the clinker during the grinding ...
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below ).
Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]
In civil engineering, concrete leveling is a procedure that attempts to correct an uneven concrete surface by altering the foundation that the surface sits upon. It is a cheaper alternative to having replacement concrete poured and is commonly performed at small businesses and private homes as well as at factories, warehouses, airports and on roads, highways and other infrastructure.
Air entrainment in concrete is the intentional creation of tiny air bubbles in a batch by adding an air entraining agent during mixing. A form of surfactant (a surface-active substance that in the instance reduces the surface tension between water and solids) it allows bubbles of a desired size to form.
During this steam pressure hardening process, when the temperature reaches 190 °C (374 °F) and the pressure reaches 800 to 1,200 kPa (8.0 to 12.0 bar; 120 to 170 psi), quartz sand reacts with calcium hydroxide to form calcium silicate hydrate, which gives AAC its high strength and other unique properties.
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A precast concrete walled house under construction An example of low-quality precast concrete with exposed dowels, connectors, indications of cracks, and malformations, even during its installation, Barangay Lantic, Carmona, Cavite, Philippines Interior view of the walls, supports, and roof of a precast commercial shop in Williston, North Dakota, US.