What did the Romans build with concrete?

The word concrete comes from the Latin word "concretus" (meaning compact or condensed), the perfect passive participle of "concrescere", from "con-" (together) and "crescere" (to grow).

Perhaps the earliest known occurrence of cement was twelve million years ago, when a natural deposit formed after an occurrence of oil shale naturally combusted while adjacent to a bed of limestone. These ancient deposits were investigated in the 1960s and '70s. On a human time-scale, lime mortars were used in Greece, Crete, and Cyprus in 800 BC, and the Romans used concrete extensively from 300 BCE to 476 CE, a span of more than seven hundred years.

Concrete was used for construction in many ancient structures.

Pont du Gard

During the Roman Empire, Roman concrete (or opus caementicium) was made from quicklime, pozzolana and an aggregate of pumice. Its widespread use in many Roman structures, a key event in the history of architecture termed the Roman Architectural Revolution, freed Roman construction from the restrictions of stone and brick material and allowed for revolutionary new designs in terms of both structural complexity and dimension.

Concrete, as the Romans knew it, was a new and revolutionary material. Laid in the shape of arches, vaults and domes, it quickly hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick.

Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete (ca. 200 kg/cm2). However, due to the absence of reinforcement, its tensile strength was far lower than modern reinforced concrete, and its mode of application was also different:

Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice, often consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.

The widespread use of concrete in many Roman structures has ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges have masonry cladding on a concrete core, as does the dome of the Pantheon.

SOURCE OF THE INFORMATIONS ABOVE : WIKIPEDA- en / Information about the use of concrete by the Romans.

Notice: The writing above is a fragment of the Wikipedia's page named "Concrete" and aims to provide a more complete reference about the characteristics of the ancient concrete.