Experimental Procedures of Accelerated Aging and Evaluation of Effectiveness of Nanostructured Products for the Protection of Volterra (Italy) Panchina Stone

The aims of the research were to evaluate the effectiveness of the application of nanostructured products on Volterra calcarenite stone and to define the experimental conditions and procedures of accelerated aging tests, able to simulate different degradation on the studied lithotype. The work focused on methods of performing accelerated aging tests in order to simulate different effects of environmental decay involving stone used on a historical site. The rock samples were examined before and after three treatment types: cyclic salt spray chamber, cycles of freezing–thawing and cycles of thermal shock. After each artificial aging cycle, changes in appearance were noted and chemical and physical properties were measured so that the differences between untreated and treated samples could be compared. After applying nanostructured products on the sample surfaces, and assessing the effects of the accelerated aging, the protective performance of the coatings was evaluated using the contact angle test to evaluate the surface hygroscopicity. Moreover, scanning electron microscope (SEM-EDS) analysis was performed before and after each application of nanostructured coating to evaluate changes in the surface morphology. Results demonstrated that Panchina stone showed a high durability to the aging tests, and artificial degradation effects were not largely visible. The nanostructured products seem to be suitable for stone protection by virtue of their good compatibility and effectiveness.