ABSTRACT
This chapter covers the wide ranging sources from which min eral admixtures are derived. An attempt is also made to give the current production and utilization rates in various parts of the world. However, due to rapid changes in industrial and eco nomic conditions, the production and utilization rates of indi vidual mineral admixtures are subject to wide fluctuations. For example, traditional mineral admixtures were derived mostly from natural volcanic materials and calcined clays or shales. With the availability of industrial by-products, such as coal ashes and metallurgical slags, in many countries the economic and ecological considerations have forced the substitution of natural materials by industrial by-products.
