Soluble Salt Migration in the Composite Masonry of the Ming Dynasty Kangling Tomb, the Ming Tombs, Beijing

Abstract

The Ming Dynasty Kangling Tomb, one of the Ming Tombs in Beijing, exhibits notable salt weathering phenomena on the stone–brick composite structures of its Ming Tower (Minglou). Field observations reveal visible efflorescence, granular disintegration, and color changes along the lower stone courses and arch bases. This study investigates the migration and accumulation of soluble salts within different masonry materials and interfaces.
A combination of surface mapping, photographic documentation, and Literature search was conducted to identify the patterns and mechanisms of salt transport. The results show that salt accumulation is concentrated at the junctions between the dense limestone blocks and porous grey bricks, where moisture movement and evaporation gradients are most pronounced. The observed white crusts and blackened damp areas suggest alternating cycles of capillary rise, evaporation, and recrystallization.
These findings indicate that the heterogeneous nature of the masonry – particularly the contrast in porosity and permeability between stone and brick – plays a crucial role in directing salt migration. The study provides insights into the deterioration processes of composite heritage structures and highlights the importance of moisture and salt management in conservation planning for the Ming Tombs.