Predicting the Strength of Granitic Stones after Freeze–Thaw Cycles: Considering the Petrographic Characteristics and a New Approach Using Petro-Mechanical Parameter

The strength of stones is a determining factor for evaluating their durability after freeze–thaw (F–T) phenomenon in cold regions. In this study, a new petro-mechanical predictor parameter (PMPP) is proposed for predicting the strength of granitic stones after F–T. This criterion considers two parameters namely initial strength (IS) and petrographic characteristics including mineralogical composition and textural features. For this purpose, eight samples of granitic stones were selected to determine their IS (uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS)), mineralogical indices (including Feldspathic Index (IF), Coloration Index (IC), and Quartz-Feldspar Index (IQF)), and textural indices (including Texture Coefficient (TC), Index of Interlocking (g), Index of Grain Size Homogeneity (t), and Index of Mean Grain Size (MGS)). Then, the samples were subjected to the F–T test up to 60 cycles, and their UCS and BTS were measured. The results showed the F–T has the most and least effect on BTS and UCS, respectively. Also, the results obtained from correlation equations prove that influence of mineralogical indices on the UCS and BTS of samples after F–T is more significant than textural indices. Moreover, among the mineralogical and textural indices, IQF and MGS indicated a more significant effect on the UCS and BTS of samples after F–T. Finally, it was concluded that the PMPP has acceptable accuracy for predicting the UCS and BTS of samples after F–T, and thereby the durability of stones. Consequently, PMPP saves much time and provides significant practical advantages for a rapid durability assessment of granitic stones after F–T.