The article investigates the susceptibility of two Portuguese limestones, Moleanos (MO) and Semi-Rijo (SR), to salt fog degradation for enhancing stone selection methods in sustainable stone facades. Salt weathering is a significant factor in the deterioration of stonework, facades, and masonry.
The study focused on analysing salt fog decay cycles to improve stone-cladding dimensioning practices. Results indicated that salt fog exposure caused weight loss, increased porosity, and mechanical decay in both limestones. Flexural strength notably decreased in MO and SR after exposure to salt fog. Microscopic analysis revealed that salt crystallisation led to granular disaggregation, bioclast removal, and increased microfissures and pores in the limestones.
The research emphasises the importance of complementary assessment methods, such as flexural strength and dynamic elastic modulus, which are crucial for stone cladding selection but not included in the reference European standard (EN 14147).
The findings provide valuable insights for selecting suitable stones based on their physical and mechanical properties to withstand environmental challenges. Recommendations include regular visual inspections and cleaning to prevent salt accumulation and crystallisation on facades.
The study serves as a preliminary work identifying the physical-mechanical deterioration of sedimentary stones after salt fog exposure, with future research planned to explore the effects of prolonged salt fog cycles and combined salt fog and CO2-rich environment simulations on stone properties in urban settings.
