The effect of water on the strength of building stones

Problem statement: Water is one of the main causes of stone decay and the presence of water alone inside a stone could cause a decrease in its mechanical strength. In order to study the effect of water on the mechanical strength of stones, three Italian stones, which have historically been used for balconies, have been studied: Pietra di Luserna, Pietra Verde Argento and Pietra di Courtil. Approach: A comparison has been made between the effect of artificial ageing, by means of freeze and thaw cycles (where the increase in pores produced by iced water mechanically weakens the stone) and the effect of saturation on sound specimens subjected to flexural strength tests. Results: The results have shown that the three stones are very resistant to freeze and thaw cycles, but their mechanical strength decreases in wet condition. Conclusion/Recommendations: On the basis of the obtained results, it can be stated that mechanical strength values in wet conditions should be considered, in the planning of structural stonework for exterior use. As demonstration the case of a Pietra di Luserna balcony, where fault is occurred, a is reported.