Investigation of effect of freeze-thaw on mechanical properties of Upper red formation sandstones based on measurement of P-wave velocity and porosity

The aim of this research is the estimation of uniaxial compressive strength and modulus of elasticity of Upper Red Formation sandstones using the physical properties in different cycles of freeze-thaw test. For this purpose, 6 large rock blocks from different locations of Upper Red Formation in southwestern of Qom were obtained. In this research, the freeze-thaw test was carried out in 30 cycles. Freeze–thaw test was carried out for 30 cycles and the variations of P-wave velocity, porosity, uniaxial compressive strength and modulus of elasticity of specimens were determined after every 10 cycles according to ISRM. The results of this study show that an increase in number of freeze–thaw cycles decreases uniaxial compressive strength, modulus of elasticity and P wave velocity, whereas the effective porosity increases. Based on this, it was observed that uniaxial compressive strength of specimens decreases between 41 and 85%, whereas the modulus of elasticity decreases between 47 and 70%. Finally, for prediction of strength properties of selected sandstones using the P-wave velocity and effective porosity in different cycles of freeze-thaw test, a series of predictive relationships were also proposed.