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Water reducers are special chemical products added to a concrete mixture before it is poured. They are from the same family of products as retarders . The first class of water reducers was the lignosulfonates which has been used since the 1930s.
Superplasticizers (SPs), also known as high range water reducers, are additives used for making high-strength concrete or to place self-compacting concrete. Plasticizers are chemical compounds enabling the production of concrete with approximately 15% less water content. Superplasticizers allow reduction in water content by 30% or more.
A cement accelerator is an admixture for the use in concrete, mortar, rendering or screeds. The addition of an accelerator speeds the setting time and thus cure time starts earlier. [1] This allows concrete to be placed in winter with reduced risk of frost damage. [2]
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.
Different types of pumps are suitable for different applications, for example: a pump's maximum lift height also determines the applications it can be used for. Low-lift pumps are only suitable for the pumping of surface water (e.g., irrigation, drainage of lands, ...), while high-lift pumps allow deep water pumping (e.g., potable water pumping ...
Raising the water content or adding chemical admixtures increases concrete workability. Excessive water leads to increased bleeding or segregation of aggregates (when the cement and aggregates start to separate), with the resulting concrete having reduced quality. Changes in gradation can also affect workability of the concrete, although a wide ...
Likewise, time reduction reduces installation costs. Regular, membrane-backed concrete can cost around US$5 per square foot, although prices can vary based on the application. The one-step installation process of hydrophobic concrete brings the cost down to about US$3.20 per square foot.
A retarder is a chemical agent that slows down a chemical reaction.For example, retarders are used to slow the chemical reaction hardening of plastic materials such as wallboard, concrete, and adhesives.