पोज़ोलाना

Also known as pozzuolana, pozzolanic ash, pulvis puteolanus

thumb|right|Pozzolana from Mount Vesuvius volcano, Italy Pozzolana or pozzuolana ( , ), also known as pozzolanic ash (), is a natural siliceous or siliceous-aluminous material that reacts with calcium hydroxide in the presence of water at room temperature (cf. pozzolanic reaction). In this reaction insoluble calcium silicate hydrate and calcium aluminate hydrate compounds are formed possessing cementitious properties. The designation pozzolana is derived from one of the primary deposits of volcanic ash used by the Romans in Italy, at Pozzuoli. The modern definition of pozzolana encompasses any