A pozzolana is essentially a siliceous material, which, while in itself possessing no cementitious properties, will in finely divided from and in the presence of water, react with calcium hydroxide at ordinary temperatures and form compounds having cementitious properties
Pozzolanas used in the manufacture of Portland Pozzolana Cement (PPC) may be natural materials, such as shales, tuffs, volcanic ashes, pumicites and diatomaceous earth. Materials processed by calcination of soil, or fly ash, etc., are also used in the manufacture of pozzolana cement.
Portland pozzolana cement is produced either by grinding together portland cement clinker, pozzolana and gypsum, or by uniformly and intimately blending portland cement and fine poazolana