The use of volcaniclastic material in Roman hydraulic concretes: a brief review

Abstract

The realization that the addition of volcaniclastic material to hydrated lime cements produced a concrete that was not only waterproof but would also set under water revolutionized the building programmes of the Roman Empire. The material became known as pulvis Puteolis (dust of Puteoli) from the Latin name for modern Pozzuoli on the Bay of Naples. Pozzuoli itself is the root of 'pozzolana', meaning any material (in most natural cases, volcanic in origin) that is capable of producing a hydraulic (waterproof) set when combined with lime cement. A reaction between quicklime (CaO) and volcanic ash promotes the growth of phases that, rather than reverting to calcium carbonate on curing, as in nonhydraulic cements, produce a hard, watertight material. Although volcanic materials were the aggregates of choice in the building projects of hnperial Rome, being locally derived, abundant and relatively easily quarried, their hydraulic properties were soon fully realized, perhaps as a result of observations of naturally calcite-cemented scoria and ash flows in sea water or from experimental building. Away from the Imperial centre, terrestrial architecture involving waterproofing (baths and cisterns) effectively used waste ceramic sherds as a substitute for volcanic ash. However, for marine and riparian architecture, volcanically derived pozzolanic cements were the preferred material of use.

A Comparison of the Chemical and Engineering Characteristics of Ancient Roman Hydraulic Concrete With a Modern Reproduction of Vitruvian Hydraulic Concrete*

“…Our samples have shown that the aggregate could be either tuff, or local limestone and sandstone, in the approximate proportions 35:65, aggregate to mortar. There are useful discussions of pozzolana and pozzolanic mortars and concretes in Blake (1947, 41–44, 313–315); Massazza (1988); Lugli (1957, 394–401); Turriziani (1964); Siddall (2000); Lancaster (2005, 51–67); Oleson et al . (2006).…”

The use of volcanic materials for the manufacture of pozzolanic plasters in the Maya lowlands: a preliminary report

“…According to Dandrau (2000), hydraulic plasters were used by the Minoans, although the Romans are generally recognized to be the first to use pozzolanic aggregates systematically by mixing slaked lime with volcanic ash from the town Pozzuoli, a source of volcanic ash from Vesuvius (Siddall, 2000). The town gave its name to the term ''pozzolanic aggregates'', which is applied to materials that have reactive properties when mixed with lime.…”

The production cycle of lime‐based plasters in the Late Roman settlement of Scauri, on the island of Pantelleria, Italy

“…Archaeometric studies concerning Roman mortars and plasters have greatly increased in the last decade, enabling the acquisition of new knowledge about the technological aspects of their manufacture, and the nature of the raw materials used (Belfiore et al, ; De Luca et al, ; Jackson et al, ; Lezzerini et al, ; Pavìa & Carò, ; Siddall, ). In this paper, petrographic and chemical analyses of a representative set of 20 samples of Late Roman lime‐based plasters were carried out, to investigate both the processing cycle and the provenance of the raw materials used.…”