Assessment the stones compatibility based on salt weathering tests

The current study aims to assess the compatibility between tuffeau and Richemont stone exposed to salt weathering, the most frequent physical-mechanical weathering process. Different experimental tests, both in macro- and in micro- scale, were performed on the aged stone samples underwent 20 wetting-drying cycles using salt solution of sodium chloride. The results of the aged samples were then compared with the already results belonged to the fresh samples. In the accelerated ageing tests the stone samples were situated in two different methods: the isolated stone samples and the pair of stone samples, i.e. one tuffeau sample linked to one Richemont sample. The linked test method was adopted to simulate the in-situ situation of the stones. The main results show that the microstructural characteristics of the stone (pore size distribution, water transfer properties and tensile strength) strongly reflect the stone resistance versus the salt weathering. Moreover, the results indicate that the integrity of tuffeau stone samples increased when linked to the Richemont stone samples referring to the presence, in partial way, the compatibility between the two stones. However, the limited conditions of the salt crystallization test (i.e. only 20 wetting-drying cycles) were not sufficient to detect the complete behavior of the two stones towards the salt weathering. Therefore, the current results confirm that the compatibility assessment between the stones cannot be judged based on the results presented in this study.