ABSTRACT
Admixtures may be used in concrete mixes for a variety of purposes including accelerating or retarding the set, waterproofing, or entraining air, and some of these will have an effect on workability. However, some admixtures, known as plasticizers or superplasticizers, have been developed specifically to improve workability for placing and compacting, and others as pumping aids to avoid blockages and to widen the range of pumpable mixes. Table 10.1 summarizes the most common types of admixture and gives an indication of the effect of each on the rheological properties of the fresh concrete. Several books and reviews have dealt with the types, mode of action, and technology of these materials 1 - 4.
