Mechanical characteristics of Roman concrete and their relation with materials' composition: the case studies of Roman theatre of Aquileia and Diocletian Baths in Rome

Roman civilization is universally recognized for the development of Roman concretes which are known for their exceptional strength and mechanical properties having survived for years since the conception of numerous Roman monuments and structures. From the revival of antiquity in the renaissance era to modern day, the scholars have always posed questions spanning a wide array of topics, making up of construction techniques, the effectiveness and efficiency of these designs against time and other forces of nature. Notably, the resilience of Roman concretes, particularly Opus Caementicium, has been observed to strengthen over time. In this study, multiple samples were selected from the Theater of Aquileia and the Diocletian baths in Rome, reflecting significant differences in composition, strength, geographical provenance, and historical periods. A multidisciplinary approach was employed to gain insight into the mechanical characterization of these samples, focusing on the relationship between material composition and mechanical properties. Analysis techniques included Optical Microscopy, Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Powder Diffraction (XRPD), and compressive and splitting strength tests. The study highlights the importance of archaeometric characterization for understanding the technological advancements and material choices of ancient civilizations, providing valuable insights for future conservation and restoration projects.