Salt weathering of sandstone under dehydration and moisture absorption cycles: An experimental study on the sandstone from Dazu rock carvings

Salt weathering significantly accelerates the deterioration of sandstone, particularly when sodium sulfate undergoes phase transitions between thenardite and mirabilite during dehydration and moisture absorption cycles. Laboratory experiments on sandstone from Dazu Rock Carvings (DRC) in China revealed that high salt concentrations (2.4 mol/L) lead to severe disintegration, while moderate levels (1.5 mol/L) cause flaking and surface salt accumulation. Damage is more pronounced under dehydration conditions, where thenardite formation exerts greater stress than mirabilite during moisture absorption. Salt migration and clay mineral distribution further influence deterioration patterns, mirroring natural weathering observed in the field. Critically, no damage occurs when salt content remains below 0.67%, offering a threshold for conservation strategies. These findings provide actionable insights for preserving DRC.

Yan, S., Xie, N., Liu, J., Li, L., Peng, L., & Jiang, S. (2022). Salt weathering of sandstone under dehydration and moisture absorption cycles: An experimental study on the sandstone from Dazu rock carvings. Earth Surface Processes and Landforms, 47(4), 977–993. Portico. https://doi.org/10.1002/esp.5298