Superplasticizers (SPs) are also known as high- range water reducers that are additive used in making high strength concrete. Plasticizers are chemical compounds that enable the production of concrete with approximately 15% less water content. Superplasticizers allow a 30% or more reduction in water content.It is chemical admixtures that are added to the concrete to improve their flowing ability, they help to reduce the amount of water in the concrete and to improve the strength and durability of concretes.
By adding superplasticizer into concrete, the performance of concrete can be changed. The performance of concrete is different, then the type of superplasticizer that needs to be added is also different. According to the different classification standard , there are many kinds of superplasticizer: ① According to the chemical composition of superplasticizer. It can be divided into: polyoxyethylene alkyl ethers, lignosulfonates and their derivatives, oxygen-containing organic acids, polyol complexes, alkylaryl sulfonates, and higher polyol sulfonates.
② According to the different superplasticizer effect of superplasticizer, it can be divided into the following categories: first, superplasticizer, also known as superplasticizer, such as polyalkylarylsulfonate superplasticizer, means that under the premise of the same slump of concrete, adding superplasticizer can enhance the superplasticizereffect of concrete, and the performance of superplasticizer is significantly improved compared with ordinary superplasticizer. Superplasticizer is widely used in all kinds of industrial and civil buildings, transportation and municipal engineering construction, such as precast concrete, prestressed reinforced concrete, cast-in-place reinforced concrete, etc. for early strength concrete, large flow concrete and precast concrete components of steam curing process, it is also suitable for high strength concrete, prestressed reinforced concrete and cast-in-place reinforced concrete Medium strength concrete and super high strength concrete. In addition, superplasticizer can also be used as superplasticizercomponent of concrete admixture.
Secondly, common superplasticizer, as a general additive (such as lignosulfonate superplasticizer) with the same slump of concrete, is widely used in various reinforced concrete, cast-in-place concrete, prestressed concrete, precast (without steam oxidation process) concrete, medium and low strength concrete, as well as mass concrete Generally speaking, common superplasticizer is widely used in large formwork construction, slip form construction, especially in concrete construction with daily minimum temperature above + 5 ℃.
Third, air entraining superplasticizer is an additive with the function of air entraining and water reducing. Air entraining superplasticizer is mainly used in antifreeze concrete, winter construction concrete, roller compacted concrete and lightweight concrete. Fourth, retarding and superplasticizeradmixture, which has dual functions of retarding and water reducing, is suitable for mass concrete, concrete with daily minimum temperature above + 5 ℃ or concrete in high temperature area, pumped concrete and slip form construction. The fifth is early strengthen superplasticizer. The superplasticizer has the function of improving early strength and water reducing. The early strength superplasticizer is suitable for the construction of aerated concrete and under the conditions of normal temperature, low temperature and negative temperature (the minimum temperature is not less than - 5 ℃), as well as the concrete engineering with early strength or anti freezing demand.