Statistical analysis of stone decay by salt mist - The cases of Rosa Arronches and SPI portuguese granites

Abstract

This study investigates the decay behaviour promoted by salt mist on “Rosa Arronches” and “SPI” Portuguese granites. These are two widely applied granites in the national and international markets, traded and exported to several countries. For the purpose of better understanding their behaviour and mechanical properties under a salt mist atmosphere two series of 150 cycles of a salt mist-controlled atmosphere was applied to sound samples. Petrographic and major mechanical properties were determined, according with European Standards, before and after the artificial weathering, and a statistical analysis of the mass loss between successive cycles was conducted using the exponential model suggested by Mutlutürk et alii (2004). The results revealed a decrease in all the mechanical properties evaluated for both granites, however without compromising their use as dimension stones, thus representing a new insight into the mechanical response to be considered, especially in regions affected by this decay mechanism.