Superplasticizer is also known as high range water reducers. Superplasticizers are synthetic water-soluble organic substances that reduce the amount of water require to achieve a certain stability of concrete, reduce water-cement ratio, reduce cement content and increase slump.
Superplasticizers are relatively a new category and improved version of plasticizers, Japan and Germany during 1960 and 1970 respectively, developed use of super plasticizers. They are chemically different from normal plasticizers. Use of super plasticizers allow the reduction of water to the extent up to 30% without reducing workability as at aim to the possible reduction to 15% in case of plasticizers.
The superplasticizers are added in concrete in small amounts but affect many properties of concrete. The use of super plasticizers is practiced for production of flowing, self compacting, self levelling and for the production of high strength and high performance concrete.
Mechanism of action of super plasticizers is more or less same as Ordinary plasticizers. Superplasticizers are more powerful as dissolving agents and they are high range water reducers. Superplasticizers are mostly used as high rise building
Super Plasticizers can produce
- At the same water cement ratio much more workable concrete than the plain ones,
- For the same workability, it permits the use of lower w/c ratio,
- As a consequence with increased strength and with lower w/c ratio, it also permits a reduction of cement content.
Also Read: What is a Concrete Admixture?
Few polymers which are commonly used as base for superplasticizers are classified as below
- Sulphonated malanie-formaldehyde condensates(SMF)
- Sulphonated naphthalene-formaldehde condensates
- Modified lignosulphonates(MLS)
- Other types
In addition to the above, in other countries the following new generation superplasticizers are also used
- Acrylic polymer based (AP)
- Copolymer of carboxylic acrylic acid with acrylic ester (CAE)
- Cross linked acrylic polymer (CLAP)
- Polycarboxylate ester (PC)
- Multicarboxylatehers (MCE)
- Combination of above.