(mainly calcium chloride) or retarders (mainly sugar derivatives-) to regulate the setting time. It has long been known that the water-cement ratio is the most important factor in controlling strength, but it is necessary to add an excessive amount of water to obtain a suitable workability.


necessary - it could also be improved by increasing the amount of cementitious material. However, it has finally been recognised that concrete made simply from cement, water and aggregates is not as strong as it should be.
materials are not durable in harsh environments (i.e., freeze-thaw cycles, seawater). Fortunately, chemical admixtures such as air-entraining
Fortunately, chemical admixtures, such as air-entraining agents, can greatly improve the durability of concrete.
In order to improve the workability of concrete at certain water-cement ratios, several organic admixtures are used. These admixtures are called

-or reduce the amount of water and cement used to get a certain strength and workability.
There is one type of water reducing agent that is particularly effective in controlling the workability of concrete. These organic, water-soluble polymers are called high-efficiency water-reducing agents, - or superplasticisers.
-or superplasticisers. An important one is poly(naphthalene sulfonate). It has been known since 1938 as a cement dispersing
It has been known as a cement dispersant since 1938. -But because the design strength of concrete has always been low, it is entirely possible to achieve the desired workability by adjusting the amount of water used. Plus

The first polymeric water reducing agent adopted by the concrete industry was a lignin derivative, lignosulfonate dispersant. -As
a by-product of the pulp industry, it is relatively cheap, can be a small price for the effect of water reduction. However, it was later discovered that the composition of this
However, it was found that the composition of this by-product was highly variable, especially in terms of sugar content, which posed a major problem in terms of retarding coagulation and air entrainment.