Structural Assessment of Ancient Masonry Structures: An Experimental Investigation on Rubble Stone Masonry

Non-destructive investigation procedures are appropriate approaches for the qualitative mechanical assessment of heritage masonry structures. This study aims to contribute to the knowledge of one of the most common ancient masonry typologies, particularly in Roman archaeological sites, the rubble stone masonry, that is the ancient opus incertum, with an extensive experimental program carried out in the archaeological site of Pompeii. The research focused on archaeological masonry structures with different states of preservation and with or without modern interventions. A non-destructive investigation procedure was carried out including detailed geometrical and material surveys, visual inspections and an extensive program of sonic pulse velocity tests, with a total of 1965 acquired velocities. The paper describes the adopted investigation protocol and detailed analysis and discusses the experimental outcomes. Comparisons with available literature data concerning different masonry typologies at the Pompeii site are also presented. Furthermore, the results of the non-destructive investigation have been compared with available mechanical information from destructive and non-destructive tests performed by the authors on Pompeii-like masonry panels. The unique set of data collected may represent a sound tool for the estimation of the mechanical parameters of the ancient masonry structures, which is a crucial step for the definition of preservation actions.