Experimental Investigation of the Influence of Freeze–Thaw Mode on Damage Characteristics of Sandstone

Abstract

The influence of rock weathering caused by freezing–thawing on stone cultural relics cannot be ignored. For immovable stone cultural relics, different parts under different environmental conditions will be under different freeze–thaw actions and suffer different degrees of damage. In this paper, three typical freeze–thaw cycle tests of sandstone are designed, namely immersion test, capillary action test, and periodic saturation test. The macroscopic and microscopic morphologies of rock samples under different freeze–thaw cycles were analyzed. Weathering indicators such as porosity, water content, wave velocity, and surface hardness were tested, as well as uniaxial compressive strength. The variation law of weathering index and uniaxial compressive strength under different freezing–thawing cycles was obtained, and the quantitative relationship between each index parameter was further analyzed. The results show that under different freezing–thawing conditions, the apparent morphology of rock samples is different, and the trend of weathering indexes is similar, but the rate of change is different. The water content of rock has a great influence on the test results of wave velocity but has little influence on the surface hardness. The function relationship between weathering index and compressive strength under different freezing–thawing modes is similar, but the fitting parameters are different. Finally, the strength and wave velocity damage factors were used to quantitatively evaluate the degree of rock weathering. The results show that the immersion freeze–thaw damage is the highest, the periodic saturated freeze–thaw damage is the second highest, and the capillary freeze–thaw damage is the least highest. This is consistent with the field observation results. The conclusion of this paper can provide reference for the detection of stone cultural relics and provides a scientific basis for the anti-weathering protection of stone cultural relics.

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“…In "cold regions" characterized by air temperatures below the freezing point, freezethaw cycles are another mechanism that contributes to the deterioration of stone [19]. Stone naturally contains pores that allow it to hold water both on the surface and inside pores for a long time [51]. The primary mechanism of rock deterioration results from the dual action of the water-ice phase transition.…”

“…The primary mechanism of rock deterioration results from the dual action of the water-ice phase transition. Alterations in the water state (liquid, solid, gas) in the pores due to variations in the ambient temperature induce deterioration of the rock structure due to the alternation between cold contraction and thermal expansion process [51]. The freezing-thawing action of the water inside the pores and fissures plays a central role in the alteration of rocks due to freezing when the temperature oscillates across 0 • C [52].…”