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The experimental set-up described in Part I of the present short two-papers series is used for the implementation of non-standardized structural tests with specimens simulating interconnected epistyles of the Parthenon Temple on the Acropolis of Athens. The aim of the study is two folded: To quantify the response of the connections when they are subjected to shear forces and also to assess comparatively the experimental data pumped with the aid of the Acoustic Emission and Pressure Stimulated Currents techniques from the interior of the specimens. It is concluded that the experimental set-up restricts in a satisfactory manner parasitic bending and torsional moments although they are not completely eliminated due to the inherent asymmetries of the specimens’ geometry. It is also proven that the data of these innovative techniques are in good qualitative and quantitative agreement with the respective ones recorded with the aid of both traditional and modern sensing techniques pumping data from the outer surface of the specimens. Moreover it is concluded that the Pressure Stimulated Currents technique could be a safe fracture predictor.

The mechanical response of marble epistyles interconnected to each other by means of metallic connectors when subjected to shear loading is studied experimentally. The study is motivated by the need of the scientific group of the Athenian Acropolis to substitute damaged ancient connections by new ones. In this direction “I”-shaped titanium connectors are placed in the grooves sculptured by ancient stonemasons in the marble blocks and the empty space is then filled by a suitable cement-based material. Guided by the experience gathered from the inspection of failed connections, which clearly indicates that failure starts at the interior of the “titanium-mortar-marble” complex, along the material interfaces, an experimental protocol was improvised, aiming at pumping data from the interior of the interconnected epistyles. For this to be accomplished innovative sensing techniques like pressure stimulated currents, digital image correlation and acoustic emission were used in conjunction with traditional ones. In the first part of this short two-paper series the experimental set-up, the materials and the specimens’ geometry are described.

An alternative solution to the problem of early detection of upcoming catastrophic fracture of structural elements made of marble is proposed. The solution is founded on the hypothesis that unique and hidden dynamic features of complex systems could be detected using the time series of events within the system assuming that they are analyzed in terms of Natural Time. In this direction acoustic emissions time series are analyzed aiming to reveal possible pre-failure indicators in case notched marble members are loaded mechanically. The experimental protocol consists of quasi-static, displacement controlled, tension tests with double edge notched tensile specimens made of Dionysos marble, which is the material widely used for the needs of the restoration project of the Parthenon Temple on the Acropolis of Athens. The results of the analysis are very promising and suggest that at least one valid pre-failure indicator can be identified, before non-reversible phenomena appear within the mass of the specimen.