Though the Romans are renowned for their use of concrete, which allowed for quick construction and liberated architects from the constraints imposed by stone-blocks that had dominated Greek and Hellenistic architecture, it should not be overlooked that heavy concrete was and remained very much an Italian phenomenon: it is found throughout the Roman empire in public architecture, but in private architecture, not so much.
One exception is the city of – what’s in a name – Itálica, near Sevilla, in Spain, which is the place from where the families of the emperors Trajan and Hadrian came. Under Hadrian, Itálica was massively extended, and in the new quarter, private construction is heavily dominated by concrete. Yet, if you look carefully, you’ll see that this is not the usual brick-faced concrete that you can see at Ostia, but it is made with pebbles instead, thus adapting a familiar building technique to a new environment.
Miko Flohr, 14/02/2020