Investigation and analysis of ancient brick carvings of the Liuhe Pagoda in Hangzhou

Abstract

The Liuhe Pagoda in Hangzhou, China, has a large number of brick carvings from the Southern Song Dynasty (1152 ce), covering an area of 464 m². However, the exquisite brick carvings in the Liuhe Pagoda have deteriorated due to natural weathering and a high-humidity environment. Through laboratory analysis and on-site nondestructive testing, the physical and chemical properties of the brick carvings of Liuhe Pagoda were investigated, and the weathering mechanism of the brick carvings was further analyzed. The brick carving of Liuhe Pagoda is composed of brick, white plastering and black coating. CaCO₃ is the main component in white plastering, and the black coating on the top surface contains Chinese lacquer. The weathering products of the brick were analyzed and a trace of CaSO₄.2H₂O was found. In addition, the brick carvings with high water content have low Leeb hardness and severe weathering. Therefore, water and soluble salt are the main factors in weathering of the brick carvings of the Liuhe Pagoda.