Current Approaches, Solutions and Practices in Conservation of Cultural Heritage
Evaluation of the Deterioration Detected in Historical Stone Structures by Thermographic Investigations: The Case of Istanbul University Faculty of Letters South Facade
Emre Veysel Şener, Gülder Emre, Ayberk Yılmaz, Gülce Öğrüç IldızThe thermal imaging method, which is a non-destructive diagnostic method for the investigation of historical stone structures, measures the heat dissipation of the materials examined and creates colored heat maps for analysis of the data. The method allows to evaluate the deterioration state of the structures, gathering information about their current preservation state and allowing to predict in advance sensitive areas of the structures where deterioration may arise in the future. Since there are differences in the heat transfer of original limestone materials, and repair mortars or imitations, the regions where dirt deposits form in the different materials and deformations of their surfaces are also different. The thermographic analyses (in particular, thermal mapping) thus allow to evaluate deterioration in the materials and help determining the factors that cause the deterioration of the structure, providing relevant data for the design of an effective conservation planning for the structures and helping the protection-repair works. This study applies the thermographic method to the evaluation of the deterioration state of the Faculty of Letters of the Istanbul University South external facade, with was built under the influence of the Second National Architecture movement and investigated by Architects Sedat Hakkı Eldem and Emin Onat. The factors causing deterioration in the structure were also investigated by visual examination, soluble salt tests, moisture analysis and conductivity measurements, the results obtained with all methods being compared. The present study is also a contribution for the identification and evaluation the possible deterioration factors acting on historical stone structures in general.