Evaluating the Durability of Afyon–İscehisar Marbles Against Salt Mist: A Mineralogical, Petrographic, and Physical Perspective

Degradation processes forming as a result of direct and indirect environmental interactions with soluble salts are important for the structural material of marble and in geotechnical applications. This is necessary, not only to identify the source and describe the material, but also to ensure the sustainability of artifacts and to be able to provide appropriate material for preservation and restoration. In this study, the durability of Afyon–İscehisar marbles (calcitic and dolomitic) to cyclic salt mist was investigated in a laboratory environment by considering weight, color, and ultrasonic pulse velocity values. Additionally, comprehensive experiments including mineralogical and petrographic investigations (polarizing microscope, X-ray diffractometry, scanning electron microscope (SEM/EDX), geochemical investigations, and physical and mechanical tests) were performed to evaluate the durability against the effect of salt mist. The results show that the calcite content in the calcitic marbles varied from 96% to 99%, while the dolomite content in the dolomitic marbles reached 64%–74%, in line with microscopic and semi-quantitative XRD analyses and geochemical investigations. The calcitic–dolomitic differentiation was tightly controlled by the magnesium (Mg) content. With the effect of salt mist, the samples had negligible weight changes (0.02% in the KH sample) and there was no significant material loss in any of the groups. For color analyses, total color differences (ΔE) in the KH and MN samples reached 4.39 and 4.06, respectively, and exceeded the human perception threshold. The dolomitic KS and PB samples and calcitic KP sample had increases identified for ultrasonic pulse velocity. Contrary to this, the GR (calcitic) sample was found to have a 15.15% reduction in ultrasonic pulse velocity. These findings provide critical selection, performance prediction and preservation criteria for Afyon–İscehisar marbles in both modern structural engineering applications and in archeological studies.