Analysis of the factors in masonry surface weathering of Ming Dynasty City Wall in Xi′an
ZHAO Guangtao1, LI Yuhu1*, ZHANG Yidan1, DU Dexin2
(1 School of Materials Science and Engineering, Shaanxi Normal University, Xi′an 710119, Shaanxi, China;2 Xi′an Museum of Hanguang Entrance of Tang Imperial City,Xi′an 710069, Shaanxi, China)
Abstract:
In surveying the weathered surface appearance on Xi′an Ming Dynasty City Wall, the white salt powders were largely found on the surface of the bricks, which greatly affect overall appearance and cause bricks into pulverization. To reveal the reasons, we analyzed the soluble salts from the surface of bricks by using X-ray diffraction(XRD), scanning electron microscopy(SEM) and ion chromatography(IC). The results showed that the main component of the soluble salt is sodium sulfate. According to the corrosion mechanism related to sodium sulfate, some simulated experiments were carried out in the laboratory, and the weathering phenomenon caused by soluble salt was investigated.
KeyWords:
The Ming Dynasty City Wall; the weathering; soluble salt; cultural heritage conservation
