Insights on physical-mechanical properties and salt weathering response of Comiso calcarenite in the Sicilian Baroque Heritage

Comiso Stone as other Sicilian carbonate lithotypes is extensively used in the Val di Noto Baroque architecture as both construction and decorative material. This study provides a petrographic and physical-mechanical characterization to evaluate its durability and response to salt weathering. Petrographic observations indicate a grain-supported texture with sparry cement, contributing to a compact rock fabric. Results show high ultrasonic pulse velocity, satisfactory compressive and flexural strength, and low water absorption, indicating reduced susceptibility to water-related decay. Salt crystallization tests reveal moderate mass variation and limited structural damage, demonstrating higher resistance to decay compared to other Hyblean calcarenites reported in the literature. The comparative analysis highlights the role of textural compactness and pore network characteristics in controlling durability. These results provide a scientific basis for assessing the long-term performance of Comiso Stone, supporting informed conservation and restoration strategies for the built heritage of south-eastern Sicily.