δ13C and δ18O Stable Isotope Analysis Applied to Indicate Sources of Water-Induced Degradation in Historic Monuments

Abstract

AbstractSamples of mortars were collected from lime and hydraulic mortars affected by environmental, mainly water induced degradation. Moisture and humidity possesses a main threat for the preservation of historic monuments. Agents of decay related with water such as acid rain, sulfate attack, acid attack, leaching action, salts attack, damage due to frost and many more can cause extensive cracks and total disintegration of historic constructions. 50 samples were obtained from historic constructions located in North Greece. Isotopic data will make possible to provide weathering gradients. The samples were characterized in terms of their isotopic, chemical and mineralogical composition. Compositional and morphological analyses were achieved using energy dispersive X-ray analysis in the scanning electron microscope. The results of micro-morphological and petrographic examination elucidate the different sources of degradation of historic mortars. Stable isotope analysis (13C and 18O) provided information relative to the origin of CO2 and water making possible to distinguish different sources of water-induced degradation. This study indicated that stable isotope analysis is an excellent tool to fingerprint the origin of water –induced degradation and to determine the weathering depth and the potential secondary degradation mechanisms.KeywordsStable isotopes13Cδ18OMortarsMineralogyDegradation