Estimating the index properties of deteriorated carbonate rocks due to freeze–thaw and thermal shock weathering

Abstract

Laboratory tests were conducted on 12 different carbonate rocks to investigate index properties of deteriorated rocks due to physical weathering. Physical weathering due to freeze–thaw and thermal shock action for 20 cycles, was simulated, following the procedure suggested by standard methods. Index properties, P-wave velocity, uniaxial compressive strength and Schmidt hardness, for the three series of the rock samples were determined for fresh, freeze–thaw and thermal shock conditions. It was found that the index properties of rocks treated with freeze–thaw and thermal shock decrease in varying levels with respect to initial values. A model equation predicting the index properties of rocks due to freeze–thaw and thermal shock treatment was developed by multiple regression analysis of measured data. This model explains decrease in index property of a deteriorated rock depending on its initial property and porosity of rock with the coefficients for a specific index property, given in the paper for the both freeze–thaw and thermal shock treatments. Model was validated by statistical tests. In order to estimate the index property for any cycle of freeze–thaw or thermal shock treatment, this model equation was incorporated into a previously suggested model to eliminate a decay constant required for that model to be determined for a specific rock in the laboratory. So, the final model equation could accurately predict a property of a deteriorated carbonate rock depending on treatment cycle, and initial index property and porosity. This was also proved by comparing the model with compressive strength data of a researcher for freeze–thaw cycles.