Properties of Lime Renders Applied to Stone Masonry Wall of the Črnelo Castle Chapel

摘要

In the diploma work a research about the properties of the new lime renders applied to historical building was carried out. udThe emphasis of the research work was on the analysis of five samples of lime façade systems that were applied to a 258-year old stone-masonry wall of the Črnelo castle chapel. Along with the in-situ tests also laboratory tests were carried out. The façade samples were composed of rough render layer (the first layer), fine render layer and of coloured lime wash applied to all façade samples. The samples of rough and fine renders differ only in the binder - aerial limes of various Slovene manufacturers were used, together with the calcareous crushed sands with different maximum sizes of aggregate (4 or 1 mm), which were the same for all samples. In the framework of in-situ tests, first properties of lime mortars connected with workability and casting of the renders were evaluated. This was done with the help of experienced masons, who applied the renders on the wall. On the hardened samples water absorption at low pressure and the depth of carbonisation of the samples of the rough renders were measured, along with the visual examinations of renders in order to detect damages due to freezing and thawing. The laboratory tests encompassed determination of flow value and density of fresh lime mortars, and compressive strength, shrinkage and water absorption of the hardened mortars. udBased on the analysis of obtained results, a conclusion can be made that for high quality of lime facades several conditions have to be fulfilled. The execution of layers has to be done in adequate weather conditions, on an adequately prepared surface of masonry wall, lime putty has to be used as binder, enough time has to be given to the separate layers to harden (at least four months for the rough render), and most of all, expertise achieved with years of practical work in the field of lime based mortars and renders is important. ud