The combined influence of mineralogical, hygric and thermal properties on the durability of porous building stones

It is a common practice to test building stones against an isolated decay factor when assessing the durability of building stones. Accordingly, the interpretation of results is often driven by the considerations of a limited number of properties thought as relevant to the action of that specific decay factor. In this way, the role of the synergies of decay processes and agents is often neglected. Contrarily, when different decay factors are included in the same experiment and the stone properties are examined conjunctly, the difficulties of isolating the effects of a specific decay factor or of isolating the contribution of "relevant" stone properties become apparent. The aim of this paper is to assess the combined contribution of mineralogical, hygric and thermal properties to the durability of different stones after exposure to laboratory-simulated cyclic decay combining wetness and temperature variations. For this purpose, 10 stone types were selected to emphasize the impact of the mineralogical heterogeneity on stone decay, in particular the coexistence of calcareous and siliceous grains and the occurrence of clays. The results emphasize the importance of considering the relations between decay factors and highlight how stone properties must be considered as a whole in order to assess and understand the durability of building stones.