Investigation on surface condition surveys and study on weathering mechanism of the stone wall at the Zhouqiao bridge ruins in Kaifeng

Since the archeological excavation of the stone wall at Kaifeng Zhouqiao Ruins in 2023, the wall has displayed prominent surface deterioration, including chalking, fissures, and biological erosion. A classified investigation and comparative statistical analysis revealed that the northern section of the wall exhibited more severe deterioration. Optical microscopy (OM), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and ion chromatography (IC) were employed to analyze representative samples of the deterioration phenomena. The results indicated that salt crystallization and chemical erosion induced by water migration constituted the primary mechanisms of weathering, while freeze-thaw cycles caused by temperature fluctuations acted as significant accelerating factors.