The exponential rise in population & urbanization has fueled the need for residential & commercial as well as infrastructure construction. This has in turn increased the use of concrete admixtures including plasticizers & super plasticizers. These are used for modifying various properties of concrete like reducing workability, retarding or accelerating hardening and improving durability. These are widely used in most of the concrete applications whether it is a small house or a large skyscraper.

Plasticizers are water reducing admixtures, which reduce the water content of concrete to a desired workability. These admixtures are organic or a combination of organic & inorganic compounds, which induce a negative charge on the cement particles. This ionic charge causes the fine cement particles to clump together forming flocs & trapping some of the water. The plasticizer molecules act as surfactants to break the ionic attraction between the fine cement particles & hence cause repulsion. This repulsion disperses the fine cement particles, releases the entrapped water & increases the flowability of the concrete mix.

These admixtures are suitable for all types of concrete & can be used in a wide variety of applications, ranging from high slump concreting to placing concrete in inaccessible locations. They are also effective in hot weather conditions & are ideal for long haul concrete delivery where the need for workability retention is important.

The chemical composition of these admixtures varies, depending on the manufacturer & type of admixture. However, the most popular are sodium, calcium and ammonium ligno sulfates. The amount of plasticizer required varies between 0.1% to 0.4% by weight of the cement. Adding 0.1 to 0.4% of plasticizers can reduce the mixing water by 5 to 15%, which naturally makes the concrete stronger.