The Susceptibility to Salt Fog Degradation of Stone Cladding Materials: A Laboratory Case Study on Two Limestones from Portugal

Abstract

The evaluation of stone cladding material suitability can be a challenge due to the way that stone physical and mechanical properties, and characteristics such as mineralogy, might influence stone performance as a cladding element in a ventilated facade application. Salts can affect natural stone performance, and one of the experimental methods available to study and predict it is through accelerated aging tests such as salt fog chamber cycles. Aging test results should include the analysis of critical stone physical–mechanical properties to fully understand decay effects. The aim of this study was to reduce the lack of knowledge regarding the implications of salt fog on certain fundamental characteristics of stone cladding requirements, such as elastic properties and flexural strength, because these are particularly important properties for ventilated facade systems. A systematic methodology based on artificial salt fog cycles in a climatic chamber, microscopic analysis, weight measurement, flexural strength, and dynamic elastic modulus was performed on two limestones from Portugal: Moleanos (MO) and Semi-Rijo (SR). This study aims to contribute to improved selection stone methods linked to more sustainable stone facades, and the experimental methodology can be further applied to other stone types, particularly the ones most selected for stone cladding applications near coastal areas. In this work, results of salt fog decay cycles are presented and discussed considering their direct contribution for a better stone-cladding dimensioning process.