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Calcium aluminates can form complex salts in combination with different types of anions.Two series of calcium aluminates are known in cement chemistry: AFm and AFt phases, being respectively mono- or tri-substituted with a given divalent anion X (e.g. SO 2− 4, CO 2− 3, or hosting a divalent impurity such as SeO 2− 4 [3]...), or with two units of a monovalent anion, e.g. OH −, Cl − ...
Common uses are in concrete blocks, concrete slabs, geotechnical fillings, lightweight concrete, water treatment, hydroponics, aquaponics and hydroculture. LECA can be easily used for plant-growing substrate. LECA is a versatile material and is utilized in an increasing number of applications.
Concrete debris was once routinely shipped to landfills for disposal, but recycling is increasing due to improved environmental awareness, governmental laws and economic benefits. Concrete, which must be free of trash, wood, paper and other such materials, is collected from demolition sites and put through a crushing machine, often along with ...
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]
Concrete is the most common choice for earth-sheltered buildings due to its strength, durability, and fire resistance. Cast-in-place concrete is employed for non-critical structural elements such as concrete foundations, floor slabs, and exterior walls with less than 6 feet (1.8 meters) of earth cover.
Using fly ash, a byproduct of coal combustion, as an additive in concrete production, is a common practice due to its environmental and cost benefits. Still, residual carbon in fly ash can interfere with air-entraining admixtures (AEAs) [ 13 ] added to enhance air entrainment in concrete for improved workability and resistance against freezing ...
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 ).
Cracks development occurs when early-age concrete is insufficiently protected against desiccation and too much water evaporates with heat because of unfavorable meteorological conditions: e.g, high temperature, direct solar insolation, dry air, low relative humidity, and high wind speed during summer, or in hot conditions. Curing is intended to ...