7 - Superplasticizers

Abstract

This chapter examines the usability, advantages, and properties of superplasticizer. Superplasticizers belong to a class of water reducers chemically different from the normal water reducers and capable of reducing water contents by about 30%. The admixtures belonging to this class are variously known as superplasticizers,” “superfluidizers,” “superfluidifiers,” “super water reducers,” or “high range water reducers.” The advantages of superplasticizers include: (1) production of concrete having high workability for easy placement, and (2) production of high strength concrete with normal workability but with a lower water content. A mix having a combination of better workability and lower than normal amount of water, or that with less cement but having the normal strength and workability are other possible applications. Reliable statistics on the extent of the use of superplasticizers are not available. The most important property of a superplasticizer is its ability of dispersing the cement particles. Electron microscopic examination reveals that in water suspensions of cement, large irregular agglomerates of cement particles form. By the addition of a superplasticizer, the material is dispersed into small particles.