Due to the various applications of concrete in the building industry and the need for concrete with special properties such as high strength and high durability and low permeability, it is necessary to use additives that improve the desired properties in concrete. One of the most widely used additives in concrete is water reducing additives which are also known as concrete plasticizer and concrete superplasticizer. These additives, by increasing the flow rate of fresh concrete, reduce the ratio of water to cement, which is the most effective factor in the mechanical properties of concrete and improves the final properties of concrete and especially increases its strength and durability.

Water reducers are additives with physical function and do not have a direct effect on the dewatering process of cement. The main component of water reducing additives are surfactants.

Factors affecting the surface are substances that are concentrated at the interface between two immovable phases and change the physical and chemical forces acting on that surface. In a mixture that does not use water-reducing materials, the cement particles stick to each other and clot. The general mechanism of action of these additives is to reduce the gravitational forces between the particles and to help separate and improve the dispersion of cement grains from each other. This mechanism, in addition to providing free movement of cement particles, due to their distance from each other, also releases water trapped in cement clots and uses it for improvement of flow of the concrete mix.

In recent years, the need to build concrete structures with more strength, has led to improvements in the quality of chemical additives in concrete, especially water reducers. Concrete plasticizers and superplasticizers are classified into three groups in terms of chemical composition:

1. Lignosulfonate compounds

2. Naphthalene sulfonate compounds

3. Melamine sulfonate compounds (practically not widely used due to lack of preservation of slump)

4. Poly carboxylate compounds

Lignosulfonates were the first materials to be used as a water-reducing additive in concrete since the 1930s. Then naphthalene formaldehyde sulfonate and melamine formaldehyde sulfonate plasticizers were developed in Japan and Germany in the 1960s.

Poly carboxylate-based superplasticizers are the newest generation of plasticizers that have been used since the 1980s and are highly regarded due to their high percentage reduction in water to cement ratio.