Classical construction techniques in 17th century Jesuit architecture. Tools for the restoration of historic heritage

Abstract

In this research were studied materials from buildings from four different locations in the Gondar region of Ethiopia. Most of these buildings were built by Jesuit missionaries in the 17th century (1610 to 1634), and have been declared World Heritage sites by UNESCO. Samples of mortars and concretes were characterized of which there were large amounts in both the walls (brick cement) and in the render on the exterior. In addition the stone used in the masonry were analysed. In the characterization of the mortars, concrete and renders were applied various analytical quantitative techniques as used in the studies conducted by. The most important quality detected was compatibility, both with other materials and with the restoration products used to improve their performance. It was also necessary to find out as much as possible about the process involved in the manufacture of these building materials, as this can affect their performance and can enable us to predict the type of decay they have suffered. The results of this research can be used in the development of suitable conservation materials and techniques to allow us to reduce the impact of previous restoration work, by ensuring compatibility with the original materials. These techniques can also be used to enhance the resistance of the material to environmental action, and in the conservation of elements of special heritage value using locally sourced materials such as natural stone masonry. They can also be applied in the production of air and hydraulic limes with natural additives that enhance the performance of the concrete, mortars and renders used in restoration.