2 nd Historic Mortars Conference HMC2010 and RILEM TC 203-RHM Final Workshop 22-24 September 2010, Prague, Czech Republic 381 I.41 Mineralogical and Petrographic Characterization of Ancient Roman Maritime Concretes from Mediterranean Harbours Gabriele Vola 1 , Marie D. Jackson 2 , John P. Oleson 3 , Christopher Brandon 4 and Robert L. Hohlfelder 5 1 CTG Italcementi, Laboratories Dept., Bergamo, Italy, g.vola@itcgr.net 2 Northern Arizona University, USA, Marie.Jackson@nau.edu 3 University of Victoria, Canada, jpoleson@uvic.ca 4 Pringle Brandon Architects, UK, Chris-Brandon@pringle-brandon.co.uk 5 University of Colorado at Boulder, USA, Robert.Hohlfelder@Colorado.edu Abstract Eleven hydraulic concretes from ancient Roman harbours around the Mediterranean seacoast were drilled by the Romacons team in 2002–2009. In 2008–2009 the same team extracted three new cores from a reproduction of a Vitruvian concrete pila, cast in seawater at Brindisi harbour in 2004, and previously cored at 6, 12 and 24 months curing. New geochemical and mineralogical analyses of representative ancient mortars, and the concrete reproduction in Brindisi, are summarized here. In addition, the progress of the pozzolanic reaction in the various hydraulic concretes is evaluated, through compositional and microstructural examinations. 1 Drill cores from ancient Roman harbour concretes Hydraulic, pozzolanic concretes, first developed by the Romans in the 2nd century BCE, were widely used in important harbour constructions along the Mediterranean seacoast. The excellent durability of these structures has allowed them to persist, intact, in seawater for 2000 years. The purpose of this paper is to summarize chemical, mineralogical and petrographic data for cores of Roman marine structures drilled by the ROMACONS group between 2002-2009 in eleven different harbours, and a historically accurate experimental pila cast under sea water in 2004 in the modern harbour of Brindisi [1, 2, 3]. The first group was drilled in 2001-2008 from harbours along the Italian peninsula, from the ports of