Roman concrete

Евсеенков А.С.

Roman concrete, or opus caementicium, was one of the key materials of ancient construction. Its use transformed the possibilities of Roman architecture, from walls and vaults to harbours and domes.

Composition

Roman concrete was based on lime mortar, stone or brick aggregate and volcanic additives. The material was laid between facings or used in massive structures.

Pozzolana

Pozzolana is volcanic ash from areas of Campania and Latium. Mixed with lime, it gave hydraulic properties: the mortar could harden in wet conditions and even under water.

Use

Roman concrete was used in baths, amphitheatres, foundations, walls, vaults, aqueducts, bridges and temples. It allowed faster and more flexible building than cut-stone masonry.

Harbours

Its use in harbour construction was especially important. Hydraulic mixtures made it possible to build moles, breakwaters and underwater foundations, strengthening the maritime infrastructure of the empire.

Domes

Concrete allowed Romans to create large vaults and domes. In these structures not only the mixture but also the lightening of upper zones with lighter aggregate was important.

Difference from modern concrete

Modern concrete is usually associated with Portland cement and reinforcement. Roman concrete worked differently: its strength depended on lime, pozzolanic reactions, aggregate and the massive geometry of the structure.

Related topics

Roman architecture, Roman aqueduct, Roman bridges, Roman temples

Literature

• Lancaster L. C. Concrete Vaulted Construction in Imperial Rome. Cambridge University Press, 2005.

• Jackson M. D. et al. Unlocking the secrets of Al-tobermorite in Roman seawater concrete. American Mineralogist, 2013.

• Adam J.-P. Roman Building: Materials and Techniques. Routledge, 1994.

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