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| Hot Weather Concrete |
If the temperature exceeds 30¡ÆC, hot weather concrete must be used for construction.
If the temperature is higher than 30¡ÆC when casting the concrete, the amount of air carried out by the water evaporation decreases, and the risk of cold joints or temperature crack due to water evaporation increases. In addition, there is a decrease in mobility and a decrease in slump during transport.
Therefore, in the summer months when the daily average temperature exceeds 25¡ÆC, the raw material is transported in portions at a time to prevent damage by the external temperature and direct sunlight. The delayed mixture is used to maintain the same material properties as the standard to prevent loss of cracks and slumps due to dry shrinkage and hydration heat.
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Cold Weather Concrete
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Concrete that is used when there is a risk of it being frozen is called a Cold Weather Concrete. In general, freezing temperatures of concrete is between -0.5¡ÆC and -2¡ÆC. It is necessary to maintain and supply the temperature of the remicon properly in winter when the daily average temperature is below 4¡ÆC.
Therefore, hot water facilities should be installed and operated for proper hot water supply, and storage facilities should be installed to prevent freezing of aggregate and other raw materials.
In addition, the mixer truck vehicle shall be equipped with a heating seal for keeping the product warm during transport.
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| Low Heat Concrete |
This is a concrete that can reduce hydration heat and suppress cracks as much as possible by mixing powder slag and fly ash with cement with low water cement rain to prevent cracks caused by hydration heat and dry shrinkage of concrete.
Low heat concrete is suitable for large building foundation and mass concrete, such as retaining walls, dams, and subways, and structures requiring water tightness and durability.
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| Mass Concrete |
Concrete structures with large cross-sectional dimensions must be constructed with mass concrete, usually slabs of wider width and thickness of greater than 80cm, or retaining wall structures with a lower limit of 50cm or more, due to the large temperature rise caused by cement hydration.
Mass concrete is a concrete intended to reduce temperature rise by using low-heating cement such as heavy duty Portland cement, furnace cement and fly ash cement. If low heat cement is used, it is recommended that long-term age of 91 days be used as the standard for combination strength.
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| Lightweight Concrete |
Due to the recent trend of high-rise and large structures, the characteristics of the concrete being heavier than its strength has intensified the flaws of some concrete.
Concrete with a base weight of 2.0 or less is called light weight concrete, and it is manufactured to improve these defects and to provide them with a high performance.
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| High Strength Concrete |
With high strength concrete, the material effect per unit area is so high that large space can be secured through the minimization of component sections in designing process. This concrete also provides a secondary effect of reducing the weight.
Not only is it good in construction due to its high liquidity, but it can also reduce air by expressing high intensity in a short period of time, and it can be used by changing properties such as strength, slump and air mass depending on design and construction conditions.
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| Fluidized Concrete |
Fluidized concrete is a concrete prepared by adding a fluidizer to increase liquidity.
This does not change the quality of concrete, but improves its construction ability, such as brushing and composing, and is useful for preventing temperature cracks as well as improving its quality due to reduction of unit quantity and unit cement volume.
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| Underwater Concrete |
Concrete construction under water should be done carefully as material separation is easy, quality is uneven, and reinforcement is less attached.
Underwater concrete gives high viscosity and fluidity so that watertight and durable concrete can make perfect structures underwater.
The unit cement volume and fine aggregate ratio should be large to give the concrete strong viscosity and liquidity to prevent material separation underwater, especially to prevent cement from leaking into the water, thereby reducing strength and durability.
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| Watertight Concrete |
Water tight concrete structures include underground structures, repair structures, reservoirs, and water supply facilities in which the appearance, stability, durability, functionality, and maintenance are affected by water penetration.
Watertight concrete is used with a large amount of unit thick aggregate to increase water density.
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| Prepacked Concrete |
Concrete made by filling a mold with thick aggregate with a constant elevation in advance and injecting special mortar into the air gap between these thick aggregates with appropriate pressure is called pre-packaged concrete. |
| Shotcrete |
Shotcrete, a spray concrete, is used for tunneling, slope fabrication, lining of large communal structures, and covering of steel structures by spraying mortar or concrete transported through pipes using compressed air.
Manufacturing methods include dry and wet construction, and generally use Portland cement.
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| Porous Concrete (No-Fine Aggregate Concrete) |
It is a water-resistant concrete specially mixed with aggregate, cement, water, and pigments
It has better permeability, maintainability, and ventilation than conventional asphalt and concrete, which enables improved breathing with packaging materials and land to provide better harmony between the modern cities and the natural environment.
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