"සිමෙන්ති" හි සංශෝධන අතර වෙනස්කම්

 

==History of the origin of cement==

It is uncertain where it was first discovered that a combination of [[Slaked lime|hydrated non-hydraulic lime]] and a [[pozzolan]] produces a hydraulic mixture (see also: [[Pozzolanic reaction]]), but concrete made from such mixtures was first used on a large scale by [[Roman engineering|Roman engineers]].<ref>Hill, Donald: ''A History of Engineering in Classical and Medieval Times'', Routledge 1984, p.&nbsp;106.</ref> They used both natural pozzolans ([[trass]] or [[pumice]]) and artificial pozzolans (ground brick or pottery) in these concretes. Many excellent examples of structures made from these concretes are still standing, notably the huge [[monolith|monolithic]] [[dome]] of the [[Pantheon, Rome|Pantheon]] in [[Rome]] and the massive [[Baths of Caracalla]].<ref>[http://web.archive.org/web/20061018162743/http://www.chamorro.com/community/pagan/Azmar_Natural_Pozzolan.pdf Pure natural pozzolan cement.]</ref> The vast system of [[Roman aqueduct]]s also made extensive use of hydraulic cement.<ref>[http://www.yale.edu/ynhti/curriculum/units/2006/4/06.04.04.x.html Aqueduct Architecture: Moving Water to the Masses in Ancient Rome.]</ref> The use of structural concrete disappeared in medieval Europe, although weak pozzolanic concretes continued to be used as a core fill in stone walls and columns.