ABSTRACT
It is often stated that well-designed, compacted and cured concrete should not need an admixture. However, when all the practical aspects of a situation are considered such dogmatism can seldom be justified. The author’s opinion is that, with the complexity of castings, the chance to reduce water contents for the same workability, and with the many other advantages that admixtures can bestow, there are few cases where their non-use can be justified. However, one point that needs to be emphasised is that admixtures are used at relatively low concentrations and over or under dosage can lead to potentially disastrous results. Control of the basic ingredients of aggregate, cement and water must be strict because if there is any doubt about this there is no point in using admixtures. The admixtures are used to make good concrete products better, not to make poor or mediocre concrete good.
