Concrete
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Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid. It is the second-most-used substance, the most widely used building material, and the m
A single concrete block, as used for construction
Exterior of the Roman Pantheon, finished 128 AD, the largest unreinforced concrete dome in the world.
Interior of the Pantheon dome, seen from beneath. The concrete for the coffered dome was laid on moulds, mounted on temporary scaffolding.
Opus caementicium exposed in a characteristic Roman arch. In contrast to modern concrete structures, the concrete used in Roman buildings was usually covered with brick or stone.
Roman concrete
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Roman concrete, also called opus caementicium, was used in construction in ancient Rome. Like its modern equivalent, Roman concrete was based on a hydraulic-setting cement added to an aggregate.
The Pantheon in Rome is an example of Roman concrete construction.
Caesarea harbour in Roman Judaea, an example of underwater Roman concrete technology on a large scale
The "Temple of Mercury" in Baiae, a Roman frigidarium pool of a bathhouse built in the 1st century BC containing the oldest surviving concrete dome, and largest one before the Pantheon.
Example of opus caementicium on a tomb on the ancient Appian Way in Rome. The original covering has been removed.