Concrete is a composite material made up of various elements like aggregates (fine and coarse), cement, water and other constituents. It is a very important construction material in our everyday life. It is widely used in construction of buildings, bridges and roads. Concrete is the most popular and durable material due to its strength and versatility. The compressive strength of concrete increases with lower water-cement ratio, but its workability decreases with increased W/C ratio. To improve the workability of concrete, admixtures are added to it.
The most commonly used admixture is concrete plasticizer. It reduces the water content of concrete and improves its flowability. However, it has some limitations as its effect on concrete is limited and also it affects the hydration of the cement. Concrete super plasticizer is an admixture which reduces the water requirement of concrete up to 30 percent without affecting its workability. It is a hydrodynamic surfactant which binds cement particles by reducing the friction between them and thus improves the flowability of concrete. It also allows for lower w/c ratio and saves cement.
Achieving a high slump at the mixing site is very important to make sure that proper concrete is placed at the final place. But maintaining such a high slump over long distances is challenging because of the inefficient laboratory mixers and other reasons. Using retarders to control the slump loss at final point is possible, but this method is expensive and uneconomical. Using super plasticizer or a combination of retarder and superplasticizer is an alternative solution to maintain a high slump over longer durations.