During the last few years, in Egypt, there has been an increased acceptance of the advantages of replacing part of the commonly used Portland cements by fine additives, namely, pulverized fuel ash (PFA), ground granulated blast-furnace slag (GGBS) and silica fume (SF). These materials are well known to improve the concrete properties such as lower heat output, improved sulfate resistance, alkali silica reaction and improved general durability. In addition, the existing of international specification for these materials (1 – 3) has lead to the recommendations to be utilized in many major projects in order to attain specific concrete properties.

This paper presents a brief history, the production methods, the chemical composition and the physical properties as well as the hydration characteristics of these materials.