Building for Eternity: The History and Technology of Roman Concrete Engineering in the Sea

One marker of the majesty of ancient Rome is its surviving architectural legacy, the stunning remains of which are scattered throughout the circum-Mediterranean landscape. Surprisingly, one truly remarkable aspect of this heritage remains relatively unknown. There exists beneath the waters of the Mediterranean the physical remnants of a vast maritime infrastructure that sustained and connected the western world’s first global empire and economy. The key to this incredible accomplishment and to the survival of structures in the hostile environment of the sea for two thousand years was maritime concrete, a building material invented and then employed by Roman builders on a grand scale to construct harbor installations anywhere they were needed, rather than only in locations with advantageous geography or topography.
This book explains how the Romans built so successfully in the sea with their new invention. The story is a stimulating mix of archaeological, geological, historical and chemical research, with relevance to both ancient and modern technology. It also breaks new ground in bridging the gap between science and the humanities by integrating analytical materials science, history, and archaeology, along with underwater exploration. The book will be of interest to anyone interested in Roman architecture and engineering, and it will hold special interest for geologists and mineralogists studying the material characteristics of pyroclastic volcanic rocks and their alteration in seawater brines. The demonstrable durability and longevity of Roman maritime concrete structures may be of special interest to engineers working on cementing materials appropriate for the long-term storage of hazardous substances such as radioactive waste.
A pioneering methodology was used to bore into maritime structures both on land and in the sea to collect concrete cores for testing in the research laboratories of the CTG Italcementi Group, a leading cement producer in Italy, the University of Berkeley, and elsewhere. The resulting mechanical, chemical and physical analysis of 36 concrete samples taken from 11 sites in Italy and the eastern Mediterranean have helped fill many gaps in our knowledge of how the Romans built in the sea. To gain even more knowledge of the ancient maritime technology, the directors of the Roman Maritime Concrete Study (ROMACONS) engaged in an ambitious and unique experimental archaeological project – the construction underwater of a reproduction of a Roman concrete pier or pila. The same raw materials and tools available to the ancient builders were employed to produce a reproduction concrete structure that appears to be remarkably similar to the ancient one studied during ROMACON’s fieldwork between 2002-2009.
This volume reveals a remarkable and unique archaeological project that highlights the synergy that now exists between the humanities and science in our continuing efforts to understand the past. It will quickly become a standard research tool for all interested in Roman building both in the sea and on land, and in the history and chemistry of marine concrete. The authors also hope that the data and observations it presents will stimulate further research by scholars and students into related topics, since we have so much more to learn in the years ahead.

Table of Contents

1. The Technology of Roman Maritime Concrete (J.P. Oleson, M. D. Jackson)
1.1. Introduction
1.2. The unique character of Roman maritime concrete.
1.3. Recent research on Roman concrete.
1.4. ROMACONS research questions
1.5 Summary of the archaeological and engineering significance of the ROMACONS analyses

2. Ancient Literary Sources Concerned with Roman Concrete Technology (J. P. Oleson)
2.1. Theophrastus
2.2. M. Porcius Cato
2.3. Vitruvius Pollio
2.4. Q. Horatius Flaccus
2.5. P. Virgilius Maro
2.6. Strabo
2.7. L. Annaeus Seneca
2.8. Pliny the Elder
2.9. P. Papinius Statius
2.10. Flavius Josephus
2.11. Pliny the Younger
2.12. C. Suetonius Tranquillus
2.13. Apuleius
2.14. Cassius Dio
2.15. M. Cetius Faventinus
2.16. Procopius
2.17. Inscriptions

3. History and Procedures of the ROMACONS Project (C. J. Brandon, R. L. Hohlfelder)
3.1. History of the project.
3.2. Coring equipment and procedures.

4. Narrative of the ROMACONS Fieldwork (R. L. Hohlfelder)
4.1. Portus, Fieldwork July-August 2002
4.2. Antium, Fieldwork August 2002
4.3. Cosa, Fieldwork July-August 2003
4.4. Santa Liberata, Fieldwork June 2003, September 2004, and June 2005
4.5. Caesarea Palaestinae, Fieldwork October 2005
4.6. Baianus Lacus, Sinus Baianus, and Portus Iulius (Bay of Pozzuoli), Fieldwork September 2006
4.7. Alexandria, fieldwork May 2007 (with C. J. Brandon)
4.8. Chersonesos, fieldwork September 2007 (with C. J. Brandon)
4.9. Egnatia, fieldwork May 2009
4.10. Pompeiopolis, fieldwork August 2009

5. The Brindisi Pila Reproduction (J. P. Oleson)
5.1. The reconstruction project: Methods and materials
5.2. Formwork design
5.3. Construction of the formwork
5.4. Preparation of the mortar
5.5. Placement of the mortar and aggregate
5.6. Conclusions from the reconstruction experiment

6. Maritime Concrete in the Mediterranean World (C. J. Brandon)
6.1. Important sites not sampled by ROMACONS
6.2. Catalogue of maritime concrete structures around the Mediterranean and Portugal

7. Concrete Fabrics and their Material Characteristics (M. D. Jackson and collaborators)
7.1. Introduction
7.2. Geologic materials of the concretes
7.3. Concrete mix design
7.4. Pozzolanic cementitious processes in the sea-water mortars
7.5. Material properties of the concretes
7.6. Inferences regarding durability of the ancient sea-water concrete
7.7. Summary of analytical methods

8. Roman Formwork Used for Underwater Concrete Construction (C. J. Brandon)
8.1. The Role of formwork in Roman concrete construction
8.2. A Typology of Roman formwork design for marine construction: Fixed forms
8.3. A Typology of formwork design for underwater construction: Prefabricated and floating forms
8.4. Conclusions

9. Roman Maritime Concrete Technology in its Mediterranean Context (R. L. Hohlfelder, J. P. Oleson)
9.1. Trade in pozzolana, pumiceous ash pozzolan, and caementa
9.2. Mechanisms for the spread of innovation in Roman marine construction
9.3. Conclusions: Society, trade, and technology in the Roman Mediterranean

Appendix 1: Glossary of technical terms. (J. P. Oleson, M. D. Jackson)

Appendix 2: Analyses of Maritime Concrete Taken Prior to the ROMACONS Project (C. J. Brandon, M. D. Jackson)

Appendix 3: Catalogue and Description of Concretes Drilled from Marine Structures by ROMACONS (J. P. Oleson, M. D. Jackson, G. Vola)
A3.1. Santa Liberata.
A3.2. Portus Cosanus.
A3.3. Portus.
A3.4. Portus Traiani.
A3.5. Antium.
A3.6. Baiae.
A3.7. Secca Fumosa.
A3.8. Portus Iulius.
A3.9. Egnatia.
A3.10. Brindisi.
A3.11. Chersonesos.
A3.12. Pompeiopolis.
A3.13. Caesarea Palaestinae.
A3.14. Alexandria.

Appendix 4: Mineralogical and Geochemical Analyses of Components of the Concretes (M. D. Jackson, G. Vola)

Bibliography

Index