Effects of cyclic freezing and thawing on the mechanical behavior of dried and saturated sandstone

This paper presents an experimental investigation of the effects of cyclic freezing and thawing on dried and saturated sandstone cores. Both static and dynamic tests were performed to determine the static stress-strain relationship, uniaxial compressive strength, elastic modulus, dynamic stress-strain relationship, dynamic strength and dynamic energy absorption capacity of dried and saturated sandstone specimens under different numbers of freeze-thaw cycles. The degradation in several mechanical properties were discussed, and exponential equations were introduced to describe the freeze-thaw cycling effects on the static and dynamic mechanical behaviors. The results show that both the static and dynamic mechanical properties of the dried and saturated sandstone samples decrease with an increasing number of freeze-thaw cycles. Both the static uniaxial compressive strength and dynamic strength of dried sandstone are greater than those of saturated sandstone, while both the static elastic modulus and dynamic energy absorption capacity of dried sandstone are less than those of saturated sandstone. The degradation of the dried and saturated sandstone cores mainly occurs during the first 20 freeze-thaw cycles. Moreover, the same exponential equation can be utilized to describe the freeze-thaw effects on the static behavior and dynamic behavior, with good agreement.