Experimental study on weathering mechanism of ancient bricks in Jiayuguan Wei-Jin tombs, Gansu, China

Abstract

This study focuses on the ancient bricks of Wei-Jin tombs in Jiayuguan, Gansu, China, analyzing the deterioration of the bricks under the long-term influence of natural environments and human activities. Currently, the ancient bricks exhibit various degradation diseases such as cracks, exfoliation, fracture, weathering, and microbial erosion, severely affecting the integrity of the cultural relics. Through on-site investigation and characterization testing, the physical and mechanical properties, compositional elements, pore size distribution, and thermal characteristics of the ancient bricks were analyzed. Indoor simulation experiments were conducted to study the impact of different types of environmental erosion cycles (such as H2O, HCl, NaOH, Na2SO4) on the performance and structure of the ancient bricks, the patterns and causes of deterioration were also studied. The results indicate that the cyclic effects gradually transform the porosity of the ancient bricks into lateral microcracks, which continue to expand, leading to varying degrees of degradation of performance. The extent of the impact of these cycles on the properties of ancient bricks is in descending order: Na2SO4, HCl, NaOH, H2O. H2O, NaOH, HCl, Na2SO4.