Portland pozzolana cement is ordinary Portland cement blended with pozzolanic materials ( power-station fly ash, burnt clays, ash from burnt plant material or silicious earths ), either together or separately.
32.
"For the first time, they were using plaster made of lime and pozzolana, " he said, referring to a form of volcanic ash that was also used in ancient Roman times.
33.
Pozzolana also is a decomposed tuff, but of basic character, originally obtained near Naples and used as a cement, but this name is now applied to a number of substances not always of identical character.
34.
There, in common with most Roman cements, mortars comprising high amounts of pozzolana were used in order to give what was thought to be an increased resistance to the stress-effects caused by earthquakes.
35.
During construction of the Los Angeles Aqueduct, the City of Los Angeles found deposits of Tuff at Fairmont Butte that closely resembled German Trass and Italian Pozzolana and was an ideal ingredient to blend and use in the production of cement.
36.
The first use of concrete by the Romans was in the town of Cosa sometime after 273 BC . Ancient Roman concrete was a mixture of lime mortar, aggregate, pozzolana, water, and stones, and was stronger than previously-used concretes.
37.
The earliest evidence of settlement of the site come from finds of urns at two areas ( Cava della Pozzolana and Sorbo ) from the 8th and 9th centuries BC and archaeology has revealed the presence of stable employment in the area with housing and related Etruscan necropolis settlements.
38.
The corporation manufactures various types of cements, such as Portland pozzolana cement ( PPC ), Portland slag cement ( PSC ), and ordinary Portland cement ( OPC ) of varying grades-33, 43, 53 and 53S ( special grade cement for manufacture of sleepers for Indian Railways ).
39.
In provincial towns and in other parts of the Roman Empire, where the material pozzolana was not procurable, the Romans had to trust to their mortar as a cementing medium, but this, though excellent of its kind, was not of sufficient cohesive strength to allow of the erection of vaults of more than about 40 ft . span, which were generally built in rubble masonry.
40.
Hydraulic lime contains lime with silica and / or alumina and sets with exposure to water and can set under water . " Natural hydraulic lime " ( NHL ) is made from a limestone which naturally contains some clay . " Artificial hydraulic lime " is made by adding forms of silica and / or alumina such as clay to the limestone during firing, or by adding a pozzolana to pure lime.
