- Opus caementicium
Opus caementicium was the Roman technique of constructing structures using
concrete. It was used from the beginning of the Roman republicthrough the whole history of the Roman empire.
Opus caementicium, like other forms of concrete, is made from a mix of aggregate and a binder which, when mixed with water, hardens over time. In Roman times
gypsumand lime were used as binders, but volcanic dusts such as pozzolana were favored where they could be obtained. Reinforcing elements, such as steel rebar, were not used.
In most usage the raw concrete surface was considered unsightly and some sort of
facingwas applied. Different techniques were characteristic of different periods and included:
Opus incertum": small irregular stones
Opus reticulatum": small squared blocks laid in a diamond pattern
Opus quadratum": regularly laid courses of ashlars
Opus latericium": regularly laid courses of brick
Opus spicatum": bricklaid in a herringbone pattern
Opus vittatum": Square Tuff blocks intersected by brick bands at regular and irregular distances.
Opus africanum": vertical chains of upright blocks with alternating horizontal blocks
Opus testaceum": Think horizontal brick work
* [http://archserve.id.ucsb.edu/arthistory/152k/concrete.html Roman Concrete]
*Roman Building By Jean-Pierre Adam, Anthony Mathews (1994)
* [http://www.cs.uu.nl/~wilke/aquasite/hulp/tekopusbreed.htm "Opus caementicium "Roman walls]
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