Sidonio Apollinare e la pozzolana a Costantinopoli. Temi di ingegneria portuale romana

The research on the building systems of the ports in Roman times is now enriched by the testimony of Sidonius Apollinare on the use in Constantinople of the pulvis puteolanus (pozzolana) coming from the Phlegraean Fields, near Naples. This is not surprising, since the precious ingredient, recommended by Vitruvius as an element that simplified the constructions at sea, was found in the concrete of various ports in the eastern Mediterranean. The construction procedures were based on wooden formworks, as a temporary or perennial containers, directly resting on the seabed or on mounds of stones, in conglomerate systems or in binderless materials; the construction process for the formwork is described by Vitruvius, but other sources also allude to it. If a catalog sketch of them is nowadays possible, it is however thanks to recent archaeological prospections and excavations, which have traced, in flooded or submerged environments, a remarkable number of samples in different types.