Alveolar Weathering Mechanism of Sandstone in the Yungang Grottoes: A Coupled Process of Moisture–Mineral Interactions and Salt Crystallization

A coupled weathering mechanism involving moisture–mineral interactions and salt crystallization has been identified as the primary driver of sandstone degradation at the Yungang Grottoes, a UNESCO World Heritage site. The study reveals that illite-rich siltstone nodules and pore structure heterogeneity accelerate microcrack propagation and cavity formation due to hydration-induced clay mineral adjustments and crystallization pressure from sulfate salts like gypsum. These findings underscore the synergistic role of clay-related structural weakening and salt damage in sandstone deterioration, providing critical insights for assessing weathering risks and guiding conservation efforts in similar semi-arid environments.

Liu, Q., He, J., Wang, S., Feng, Y., Zhu, J., Ma, T., Yan, H., & Luo, H. (2025). Alveolar Weathering Mechanism of Sandstone in the Yungang Grottoes: A Coupled Process of Moisture–Mineral Interactions and Salt Crystallization. International Journal of Architectural Heritage, 1–19. https://doi.org/10.1080/15583058.2025.2605280