Roman concrete


Roman concrete
The Pantheon in Rome, Italy, is an example of Roman concrete construction.

Roman concrete (also called Opus caementicium) was a material used in construction during the late Roman Republic through the whole history of the Roman Empire. Roman concrete was based on a hydraulic-setting cement with many material qualities similar to modern Portland cement. By the middle of the 1st century, the material was used frequently as brick-faced concrete, although variations in aggregate allowed different arrangements of materials. Further innovative developments in the material, coined the Concrete Revolution, contributed to structurally complicated forms, such as the Pantheon dome.

Contents

Historic references

Caesarea is the earliest known example to have used underwater Roman concrete technology on such a large scale.

Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana, which were volcanic sands from the sandlike beds of Puteoli brownish-yellow-gray in color near Naples and reddish-brown at Rome. Vitruvius specifies a ratio of 1 part lime to 3 parts pozzolana for cements used in buildings and a 1:2 ratio of lime to pulvis Puteolanus for underwater work, essentially the same ratio mixed today for concrete used at sea.[1]

By the middle of the 1st century, the principles of underwater construction in concrete were well known to Roman builders. The City of Caesarea was the earliest known example to have made use of underwater Roman concrete technology on such a large scale.[2]

Rebuilding Rome after the fire in 64 AD, which destroyed large portions of the city, the new building code by Nero consisted of largely brick-faced concrete. This appears to have encouraged the development of the brick and concrete industries.[3]

Example of opus caementicium on a tomb on the ancient Appian Way in Rome. The original covering has been removed.

In most usage, the raw concrete surface was considered unsightly and some sort of facing was applied. Different techniques were characteristic of different periods and included:

Material properties

Roman concrete, like any concrete, consists of an aggregate and hydraulic mortar – a binder mixed with water that hardens over time. The aggregate varied, and included pieces of rock, ceramic tile, and brick rubble from the remains of previously demolished buildings. Reinforcing elements, such as steel rebar, were not used.

Gypsum and lime were used as binders. Volcanic dusts, called Pozzolana or "pit sand", were favored where they could be obtained. The pozzolanic mortar used had a high content of alumina and silica.

Concrete, and in particular, the hydraulic mortar responsible for its cohesion, was a type of structural ceramic whose utility derived largely from its rheological plasticity in the paste state. The setting and hardening of hydraulic cements derived from hydration of materials and the subsequent chemical and physical interaction of these hydration products. This differed from the setting of slaked lime mortars, the most common cements of the pre-Roman world. Once set, Roman concrete exhibited little plasticity, although it retained some resistance to tensile stresses.

The setting of pozzolanic cements has much in common with setting of their modern counterpart, Portland cement. The high silica composition of Roman pozzolana cements is very close to that of modern cement to which blast furnace slag, fly ash, or silica fume have been added.

Compressive strengths for modern Portland cements are typically at the 50 MPa level and have improved almost ten-fold since 1860.[4] There are no comparable mechanical data for ancient mortars, although some information about tensile strength may be inferred from the cracking of Roman concrete domes. These tensile strengths vary substantially from the water/cement ratio used in the initial mix. At present, there is no way of ascertaining what water/cement ratios the Romans used, nor are there extensive data for the effects of this ratio on the strengths of pozzolanic cements.[5]

Seismic technology

For an environment as prone to earthquakes as the Italian peninsula, interruptions and internal constructions within walls and domes created discontinuities in the concrete mass. Portions of the building could then shift slightly when there was movement of the earth to accommodate such stresses, enhancing the overall strength of the structure. It was in this sense that bricks and concrete were flexible. It may have been precisely for this reason that, although many buildings sustained serious cracking from a variety of causes, they continue to stand to this day.[6]

Another technology used to improve the strength and stability of concrete was its gradation in domes. One example included the Pantheon, where the aggregate of the upper dome region consisted of alternating layers of light tuff and pumice, giving the concrete a density of 1350 kg/m3. The foundation of the structure used travertine as an aggregate, having a much higher density of 2200 kg/m3.[7]

See also

Literature

  • Jean-Pierre Adam, Anthony Mathews, Roman Building, 1994
  • Lynne C. Lancaster, Concrete Vaulted Construction in Imperial Rome, Cambridge University Press, 2005
  • Heather N. Lechtman & Linn W. Hobbs, “Roman Concrete and the Roman Architectural Revolution,” Ceramics and Civilization Volume 3: High Technology Ceramics: Past, Present, Future, edited by W.D. Kingery and published by the American Ceramics Society, 1986
  • W. L. MacDonald, The Architecture of the Roman Empire, rev. ed. Yale University Press, New Haven, 1982

References

  1. ^ Heather Lechtman and Linn Hobbs "Roman Concrete and the Roman Architectural Revolution", Ceramics and Civilization Volume 3: High Technology Ceramics: Past, Present, Future, edited by W.D. Kingery and published by the American Ceramics Society, 1986; and Vitruvius, Book II:v,1; Book V:xii2
  2. ^ Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"
  3. ^ Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"
  4. ^ N. B. Eden and J.E. Bailey, "Mechanical Properties and Tensile Failure Mechanism of a High Strength Polymer Modified Portland Cement," J. Mater. Sci., 19, 2677-85 (1984); and Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"
  5. ^ Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"; see also: C. A. Langton and D. M. Roy, "Longevity of Borehole and Shaft Sealing Materials: Characterization of Ancient Cement Based Building Materials," Mat. Res. Soc. SYmp. Proc. 26, 543-49 (1984); and Topical Report ONWI-202, Battelle Memorial Institute, Office of Nuclear Waste Isolation, Distribution Category UC-70, National Technical Information Service, U.S. Department of Commerce, 1982.)
  6. ^ W. L. MacDonald, The Architecture of the Roman Empire, rev. ed. Yale University Press, New Haven, 1982, fig. 131B; Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"
  7. ^ K. de Fine Licht, The Rotunda in Rome: A Study of Hadrian's Pantheon. Jutland Archaeological Society, Copenhagen, 1968, pp. 89-94, 134-35; and Lechtman and Hobbs "Roman Concrete and the Roman Architectural Revolution"

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Roman technology — is the engineering practice which supported Roman civilization and made the expansion of Roman commerce and Roman military possible over nearly a thousand years. The Roman Empire had the most advanced set of technology of their time, some of… …   Wikipedia

  • Concrete — This article is about the construction material. For other uses, see Concrete (disambiguation). Outer view of the Roman Pantheon, still the largest unreinforced solid concrete dome.[1] …   Wikipedia

  • Roman architecture — The Architecture of Ancient Rome adopted the external Greek architecture for their own purposes, which were so different from Greek buildings as to create a new architectural style. The two styles are often considered one body of classical… …   Wikipedia

  • Roman Architectural Revolution — The Roman Pantheon, largest dome in the world for more than 1700 years and the largest unreinforced solid concrete dome to this day[1] The Roman Architectural Revolution, also known as the concrete Revolution,[2] is a term used …   Wikipedia

  • Roman Empire — For other senses of the term, see Roman Empire (disambiguation). Imperium Romanum redirects here. For the video game, see Imperium Romanum (video game). Roman Empire Senatus Populusque Romanus (SPQR) The Senate and …   Wikipedia

  • Roman Republic — See also: Roman Republic (18th century) and Roman Republic (19th century) Roman Republic Official name (as on coins): Roma after ca. 100 BC: Senatus PopulusQue Romanus ( The Senate and People of Rome ) …   Wikipedia

  • Roman theatre (structure) — The Roman theatre is a theatre building built by the Romans for watching theatrical performances.Theatre structureThe characteristics of Roman theatres are similar to those of the earlier Greek theatres because the romans took over the Greeks, on …   Wikipedia

  • Roman art — includes the visual arts produced in Ancient Rome, and in the territories of the Roman empire. Major forms of Roman art are architecture, painting, sculpture and mosaic work. Metal work, coin die and gem engraving, ivory carvings, figurine glass …   Wikipedia

  • concrete — {{Roman}}I.{{/Roman}} noun ADJECTIVE ▪ solid ▪ bare ▪ a floor made of bare concrete ▪ fresh, wet ▪ precast …   Collocations dictionary

  • CONCRETE —    Concrete is a compound made from sand, gravel, and cement, while cement is a mixture of minerals that become hard when water is added, binding the sand and gravel into a solid mass. Although concrete is traditionally considered an Ancient… …   Historical Dictionary of Architecture


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.