Coring at Brindisi and Egnazia (Italy), May 2008.
In mid-May 2008, Brandon, Hohlfelder, and Oleson obtained two core samples at Brindisi and Egnazia. The first core was taken on 14 May from the reproduction pila built by the same team in the harbour basin of Brindisi in September 2004 (see Hohlfelder et al. 2005) (BRI.2008.01). [View of coring in progress]
This is the fourth core sample obtained from the pila; the others were taken on 19 March 2005 (BRI.2005.01), 17 November 2005 (BRI.2005.02), and 22 November 2006 (BRI.2006.01). The objective of this repeated coring is determination of the speed and the degree of curing of the Vitruvian type concrete used to construct the pila. It seems that after two years the concrete has cured to a hardness approaching that of our cores of equivalent ancient concrete, which presumably has cured completely (Oleson et al. 2006; Gotti et al. 2008).
[View of BRI.2006.01]
The 2008 core included both the top and the bottom of the block; foundation sand adhered to bottom of core. The mortar was very hard, suggesting that curing has continued, but this particular sample seems very light in aggregate. Perhaps the ancient builders added the aggregate more frequently than we did in the process of our reconstruction attempt. Small lime inclusions were observed here and there (D 0.02-0.03), but the mix is very uniform. There was no sign of day joints. Analysis of the 2008 core, which was 1.70 m in length, is in progress.
On 15 May the same team, assisted by Dr. Rita Auriemma, Universitą di Lecce and several of her students, took another core from a large concrete pila in the harbour of Egnazia, ancient Egnatia.
[map of area with indication of core locations].
Due to technical difficulties, only one of the three cores planned could be recovered (EGN.2008.01). It was taken from the taller pila near north side of ancient harbour; no. 2 on plan provided. This structure probably belongs to the Early Imperial period. Our work was overseen and assisted as well by Gianfranco Simonini and Ugo Adorante of the Carabinieri Subacquei detachment in Taranto The archaeological permit was granted by Dr. Giuseppi Andreassi, Soprintendente of the Soprintendenze per it Beni Archeologici della Puglia, through the very kind intervention of Dr. Auriemma.
[View of coring in progress]
The upper surface of the pila that was sampled lay 3.20 m below sea level, and the core, which did not quite penetrate the entire structure, was 2.6 m long. The mortar looks very granular and somewhat porous, with a wide variety of textures and colours. The aggregate was the local limestone, which is a pale yellow. It seems placed at irregular intervals, and it varies greatly in size, some of it being very large: D 0.035 to 0.60. There are frequent lime inclusions up to D 0.015; most are around D 0.005. Occasional orange to red potsherd fragments appear in the mortar, D ca. 0.003. These are probably not an intentional part of the mix. The mortar contains a significant admixture of hard, porous black lumps, D up to 0.044. The pumice lapilli have also become black, but they remain soft.
[View of EGN.2008.01]
We are very grateful to Dr. Auriemma for her assistance during this campaign, and for her gracious hospitality. Her enormous enthusiasm inspired us, just as it inspires her colleagues and students. We thank Angelo Cossa, Melissa Mele, Martina Lapertosa, Gianpaolo Colucci. and Miranda Carrieri. Fernando Zoccolo provided us with some excellent photographs of our work underwater.