Additifs légers pour béton | Agents moussants haute performance pour béton cellulaire
UN cement water reducer is a chemical admixture that decreases the amount of water used in concrete. This decrease in water allows the concrete to hydrate at a lower rate, giving it better strength and durability.
Réducteurs d'eau basse gamme, also known as normal water reducers or regular plasticizers, typically lower the amount of water in a mix by 5 à 10%. These water reducers are often used in everyday concrete applications such as driveways, trottoirs, et les murs du sous-sol.
Réducteurs d'eau de milieu de gamme, also called plasticizers or intermediate plasticizers, typically lower the amount of concrete that needs to be mixed by 15 à 20%. These admixtures are often used in concrete for flatwork, such as driveways and sidewalks, because they reduce the water needed to produce a good-quality surface.
Réducteurs d'eau haut de gamme, also known to be superplasticizers or high range admixtures, are synthetic water-soluble organic compounds that decrease the amount of water in concrete by 25 à 30%. This results in a higher fluidity of the concrete, allowing it to flow better and provide more flexibility for placements.
These admixtures are usually added to the concrete mixture at a low dosage rate, although some high-range admixtures require a higher dose for optimal performance.
Most of these admixtures have no effect on the hydration of the cement, but some – like polycarboxylates – may increase air entrainment. This will vary depending on the chemistry of the admixture and its dosage rate. It is important to select the proper admixture for the application.