Читать книгу Monument Future - Siegfried Siegesmund - Страница 280

Due to the exceptional microstructure of marble, thermal fluctuations initially cause an integral decohesion of the calcite crystal grains. This opens the intrinsically dense and tight structure to the ingress of water. Then, starting from the surface, ongoing weather-related temperature change and especially frost-thaw action accelerate the deterioration process. Conventional test methods as described in European standards are not adequate to evaluate the weathering resistance of the various types of marble. For a reliable assessment of the weathering resistance of marbles new methods are needed, covering the special deterioration mechanisms 186of marble. In this study, acoustic emissions of thermohygric treated marble were analysed and correlated with ultrasonic velocities, thermal dilatation and residual strains. The analysis of acoustic emissions enables one to determine when cracking occurs during the thermal treatment.