In-situ and laboratory analysis of historical mortars

In my diploma work I studied adequate approach to cultural heritage buildings in the case of reconstruction and/or restoration works. The focus was on historical mortars and renders and plasters. I chose the Church of St. Three Kings as an example of historical building. First on-site investigation was carried out with the help of in-situ non-destructive techniques (visual examination, damage analysis with optical microscopy) which are in case of protected and valued historic and cultural buildings often the only possible way of studying building materials. In the next step we took samples from already heavily damaged areas of renders and plasters and from the building surroundings for which we assumed that they represent the primary building materials of the church. They were later on transformed into laboratory samples - thin sections or powder samples. On the thin sections the mineral composition and microstructure of the individual mortar components were determined using optical microscopy. In addition, we also identified the individual components and detected secondary phases, which may affect the degradation of the mortar or plaster or render. From the identified mineral composition and microstructure of the components the technology of the repair mortars can be determined. In addition to the Church of St. Three Kings I also dealt with Kolizej in Ljubljana. At this building the purpose of sample analysis was different because the building was already demolished. Analyses were carried out in order to complete the investigation about the characterization of mortar, brick and plaster and render, the determination of theirs physical and mechanical properties and properties of interface between mortar and brick. Such investigations provide important and helpful information about the historical building technology, the type of applied materials and the processes of material degradation. The obtained results can be used for repair of similar buildings