What is concrete and what effect did it have on Roman construction?

Answer 1

Concrete is the well known and widely used construction material which is sometimes also called cement.

The biggest feature of Roman architecture is what historians call the Roman architectural revolution or concrete revolution. This involved the extensive use of concrete, the barrel arch and the vaulted arch.

Although the Romans were not the first in history to use concrete, they developed a type of concrete (opus caementicium) which was as resistant as modern concrete and which also set underwater (and therefore could be used to build docks for ports, dams, aqueducts and bridges). It was less fluid than modern concrete and had to be layered by hand. It was made by mixing a volcanic rock called pozzolana (which is named after Pozzuoli, a suburb of Naples) with lime and adding rubble from stones, bricks or pottery shreds as aggregates which added body to it. Concrete had technical and practical advantages. It was exceptionally strong and could span great distances when shaped into arches, vaults and domes as it could be moulded. It was layered into a formwork and it took the shape of its container. It did not require skilled labour and therefore was cheaper. It was much faster for construction than laborious masonry walls. It was safer because concrete vaulted roofing was fireproof, unlike the wooden-beamed roofs of traditional construction methods.

With this revolution the potential of the previously little used arch, vault, and dome was fully exploited for the first time. The Etruscans are said to have invented the simple (barrel) arch. The oldest example of the vaulted arch has been found in the Greek city of Pergamon (in western Turkey). The vaulted arch came into two forms: the groin arch was formed with two to four intersecting barrel arches and the rib arch, where the intersecting barrels were not of the same diameter. The Romans were first to fully appreciate the advantages of the arch and the vault. The arch has a strong load- bearing capacity. The vault has an even greater load bearing capacity and its structure is suited to support large roofs. Their construction in concrete made them easier to build and even stronger. This led to the use larger and monumental arches and vaults on a grand scale. However, the Romans did not abandon masonry arches and vaults.

Concrete and the arch and the vault were the three elements which enabled the Romans to go beyond the use of Greek methods of enclosing space by the use of cut-stone and post-and-beam or post-and-lintel structures. They became essential for large buildings and roofs. They were used to build large buildings, such as basilicas (public buildings) amphitheatres (arenas), theatres, baths, circuses (racing tracks) domes, forts and fortifications, bridges, aqueducts, and dams. They also made it possible to build bridges which were much longer than before and could cross much wider rivers and valleys.

Concrete was also used to assist the construction of the stone-paved roads. A ditch was ploughed down to the firmest layer of ground that was found. The ditch was filled with rubble from local materials or sand (when it could be found) up to one metre from the surface level. A flat floor of compacted gravel was made. Then a surface was made by embedding the stones in concrete to create the paving. The concrete was laid in two thin layers. The bottom one had coarse concrete and the top one had fine concrete.

With this revolution much longer bridges which could cross much wider rivers and valleys could be built. Trajan's bridge crossed the river Danube and although it was only functional for a few decades, it was the longest arch bridge in both total and span length for more than 1,000 years. It was 1,135 m (3,724 ft.) long, 15 m (49 ft.) wide, and 19 m (62 ft.) above the water level. If high bridges were needed, two or three tiers of arches were built on top of each other to reach the desired height. The Pont du Gard, a bridge for an aqueduct which supplied Nimes in southern France, is the greatest example of a multi-tier bridge. It has three tiers of recessed arches with the main piers in line one above the other. The first two tiers have very high and wide arches and a third tier has low and narrow arches. It reaches a height of 48.8 metres (160 feet). The lower tier is 142 metres (466 feet) long and has six aches 22 metres (72 ft.) high. The second tier is 242 metres (794 ft.) long and has eleven arches 20 metres (66 ft.) high. The upper tier is 275 metre (902 ft.) long. It originally had 47 arches (only 35 have survived) 7 metres (23 ft.) high. The width of the first pier is 6 metres (20th.), that of the second is 4 metres (13 ft.) and that of the third is 3 metres (23 ft.).

Answer 2

Concrete was a revolutionary material. It had technical and practical advantages over the Greek methods of enclosing space by the use of cut-stone and post-and-beam structures. It was exceptionally strong and hardened into a rigid mass quickly, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. It could be moulded. By layering it into a formwork it took the shape of its container. It was laid in the shape of arches, vaults and domes. It could span great distances when moulded into these shapes. it was r. Building in concrete was much quicker and cheaper than building laborious masonry walls and in addition to this did not require skilled workers, which also brought costs down. It was safer because concrete-vaulted roofing was fireproof, unlike the wooden-beamed roofs of traditional construction methods.. Roman concrete was as strong but different than modern concrete. It was less fluid and had to be layered by hand. It also set underwater.

Concrete, the arch and the vault revolutionised ancient architecture. Historians call this the Roman (or concrete architectural revolution). The barrel (simple) arch has a great load bearing capacity and the vault is suited to building large roofs. The vaulted arch or vault consists of two to four intersecting arches. Some forms of concrete were known before the Romans, but they were hardly ever used. The Romans were the first to make large scale use of concrete. They were also the first to make large scale use of the ach and the vault. Concrete, the arch and the vault became essential for large roofs and large buildings, such as basilicas (public buildings) amphitheatres (arenas), theatres, baths, circuses (racing tracks) domes, forts and fortifications and dams. They also made it possible to build bridges which were much longer than before and could cross much wider rivers and valleys. They also led to the construction of the famous bridgeworks of Roman aqueducts.

With this revolution much longer bridges which could cross much wider rivers and valleys could be built. They were built in concrete and stone and the arch were used to lengthen their spans. Trajan's bridge crossed the river Danube and although it was only functional for a few decades, it was the longest arch bridge in both total and span length for more than 1,000 years. It was 1,135 m (3,724 ft.) long, 15 m (49 ft.) wide, and 19 m (62 ft.) above the water level. If high bridges were needed, two or three tiers of arches were built on top of each other to reach the desired height. The Pont du Gard, a bridge for an aqueduct which supplied Nimes in southern France, is the greatest example of a multi- tier bridge. It has three tiers of recessed arches with the main piers in line one above the other. The first two tiers have very high and wide arches and a third tier has low and narrow arches. It reaches a height of 48.8 metres (160 feet). The lower tier is 142 metres (466 feet) long and has six aches 22 metres (72 ft.) high. The second tier is 242 metres (794 ft.) long and has eleven arches 20 metres (66 ft.) high. The upper tier is 275 metre (902 ft.) long. It originally had 47 arches (only 35 have survived) 7 metres (23 ft.) high. The width of the first pier is 6 metres (20th.), that of the second is 4 metres (13 ft.) and that of the third is 3 metres (23 ft.).

Concrete also enabled the Romans to be the first to build large and monumental domes. The best example of this is the dome of the rotunda of the Pantheon in Rome (a temple dedicated to all gods which is well preserved because it was converted into a Christian church). It is still the largest unreinforced concrete dome in the world.