Experimental study on the degradation of sandstone-petroglyph carriers in Helankou: Effects of freeze-thaw and wet-dry cycles.

The Helankou petroglyphs offer precious data for understanding the lifeways of ancient pastoralists. However, in Helankou, the combination of unique climate conditions and complex hydrochemical environments has accelerated the weathering of the sandstone-petroglyph carriers, leading to numerous petroglyphs at risk of vanishing. In response, this study employed freeze-thaw and wet-dry cycle experiments to simulate the actual environmental conditions for sandstone. Subsequently, the sandstone that underwent the experiments was subjected to further testing and analysis. The goal was to comprehensively understand the performance change patterns and micro-mechanisms in sandstone under environmental stress, thus providing scientific theoretical support for Helankou petroglyph conservation. The results indicate that under the effects of freeze-thaw and wet-dry, the degradation processes can be attributed to a diverse combination of mechanisms such as swelling-shrinkage, hydrolysis, frost heave, dissolution, and salt crystallization, which alter the physical parameters, particle size distribution, mineral composition, and structural integrity of the sandstone.