The American Concrete Institute defines a Supplementary Cementitious Material as an “inorganic material such as fly ash, silica fume, metakaolin, or ground-granulated blast-furnace slag that reacts pozzolanically or hydraulically." A pozzolan is a material that reacts with by-products of the portland cement reaction to form additional binder material. SCMs, such as fly ash or ground-granulated blast-furnace slag, are typically used to replace portland cement. Others such as silica fume or other high silica content materials, are used to enhance the properties of concrete.
Calera’s SCM is produced to perform similarly to fly ash and can be used to replace cement in concrete mixtures thereby avoiding the release of CO2 associated with the manufacture of traditional cement.