The Use of Chemical Admixtures in Concrete. Part II: Admixture-Admixture Compatibility and Practical Problems

摘要

Concrete is not just cement, stone, and water, but includes both chemical and mineral admixtures. Mixtures of admixtures can produce concretes having high flow, good cohesion, and self-leveling properties. They can be placed underwater without the aid of tremies, can expand and induce compressive stresses or reduce shrinkage, and can be placed and cured at sub-zero temperatures. Research on the aqueous phase of the cement/water/admixture system has demonstrated that admixtures control the type of products formed so that many properties can be designed into concrete. Correct combinations of admixtures produce custom-made concrete for particular jobs. Along with standard applications (water reduction, retardation, acceleration, and air entrainment), chemical admixtures are used for many special purposes. This includes conventional admixtures used in novel ways and special admixtures designed for unique applications.