In architecture the Romans achieved preëminence. The
temples and other public works of Greece seem almost insignificant beside the
stupendous edifices raised by Roman genius in every province of the empire. The
ability of the Romans to build on so large a scale arose from their use of
vaulted constructions. Knowledge of the round arch passed over from the Orient
to the Etruscans and from them to the Romans. At first the arch was employed
mainly for gates, drainage sewers, aqueducts, and bridges. In imperial times
this device was adopted to permit the construction of vast buildings with
overarching domes. The principle of the dome has inspired some of the finest
creations of ancient and modern architecture.
ROMAN USE OF CONCRETE AND RUBBLE
The Romans for many of their buildings made much use of
concrete. Its chief ingredient was pozzolana, a sand found in great
abundance near Rome and other sites. When mixed with lime, it formed a very strong
cement. This material was poured in a fluid state into timber casings, where it
quickly set and hardened. Small pieces of stone, called rubble, were also
forced down into the cement to give it additional stability. Buildings of this
sort were usually faced with brick, which in turn might be covered with thin
slabs of marble, thus producing an attractive appearance.
