1) Concrete 1) Puzzolana 
Pozzolana, also known as pozzolanic ash (pulvis puteolanus in Latin), is a siliceous or siliceous and aluminous material which 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 cement...
• (n.) Volcanic ashes from Pozzuoli, in Italy, used in the manufacture of a kind of mortar which hardens under water.
hydraulic cement discovered by the Romans and still used in some countries, made by grinding pozzolana (a type of slag that may be either ... [8 related articles]
a volcanic ash originally found near Pozzuoli near Naples which is used as an additive in mortars to achieve an hydraulic set. 
The volcanic ash (as a sand) used in the production of waterproof cement