Abstract: The paper presents data on the protection of timber from combustion and burning using the protective coatings based on alkali aluminosilicates. The results of study suggested to formulate a mix design of the alkaline aluminosilicate bond, choose fillers and to determine rates of mass loss of timber at burning and degree to which the samples under study have been deteriorated. The coated samples of wood have a minimum rate of burning – 0.002-0.0024 kg/s·m2, which is 1.3-1.6 times less than the permissible value (0.0032 kg/s·m2) and 1.5-2.3 less than that of the analogue (a commercial product "Siofarb”). In combustibility and burning behavior, the formulated coatings can be classified as hardly combustible and non- burnable materials.
Abstract: Reconstruction of a ceiling in the north-eastern wing of a former water fortress in Jeseník was carried out during the repair of its roof structure and replacement of the roof. The most damaged parts of the bearing ceiling beams were removed and partially replaced with new timber in the 70s of the 20th C. The way the work was carried out corresponded to the methods and approaches of the cultural heritage protection of that time. The replacement of damaged heads of ceiling beams with new timber that was fitted without connection to the original ceiling beams and only simply hanged on a metal girder can be considered highly provisional from the current perspective. That is why the repair of timber structures of the water fortress included also a reconstruction of the original ceiling system. Surveys focusing on the building archaeology and material assessing the condition of the incorporated timber were important for the final design of the repair and the concept of presentation of the Baroque ceilings.
Abstract: The Bothmer Castle is the biggest baroque complex in Mecklenburg-Vorpommern. It was built from 1726 to 1732 and used and maintained until 1945 by the family von Bothmer. From 1945 to 1948 it served as a field hospital, and until 1994 as a nursing home, almost without any maintenance. During that period the wooden constructions suffered a number of serious damages. Since the year 2000 the status assessment and a heritage friendly remediation was initiated by the owner, the government of Mecklenburg-Vorpommern. The report deals with the applied non-destructive and minimal-invasive testing of the wooden structures (ultrasonic investigations, endoscopy, resistography, core extraction and testing etc.) as to yield a clear picture of their status and summarizes the gained results. Furthermore, the remediation concept, developed in cooperation with the preservation authority and the owner, is presented as well as some details of its execution.
Abstract: Microwaves are electromagnetic waves of frequencies from 300 MHz to 300 GHz, corresponding to wavelengths from 1 m to 1 mm. For industrial application is allowed more frequencies, but we are mainly interested in the frequency 2 450 MHz, a wavelength of 12,2 cm, which we use in our applications. The heating occurs so that the electric field in the water molecules orient themselves according to polarization. Microwaves are a classical electromagnetic radiation with frequency lower than the solar radiation and therefore leave no residual radiation harmful to health. Using the device is completely safe, damage to health can occur only by direct irradiation of a few cm for several minutes, either intentionally or careless handling of the machine.
Abstract: The behavior of two types of modifications to glued joints utilizing epoxy resin-based adhesive was examined in a manner specified by the EN 302 standard using adherent beech wood specimens. The investigation was focused on the improvement of glued joint strength and adhesive properties. The first type of modification involved reinforcement of the epoxy-based adhesive with scattered polypropylene fibers with the aim of enhancing the tensile shear strength of the assembly. The other type of glued joint modification was the electrical discharge plasma treatment of the adherend surface. This technique for treating the surfaces of materials enables the greater spreading of liquids due to the increase in surface wettability it provides. Relevant characteristics of the test specimen – tensile shear strength and wood failure - were tested in order to analyze the behavior of the thus-modified epoxy-based adhesive-glued joints.
Abstract: The paper deals with the causes of pronounced colour inconsistency in the facades of Vrchotovy Janovice Castle. The original stone Gothic fortress has undergone a number of reconstructions, the last one taking place in the mid 19th century when the castle acquired its current neo-Gothic, romantic look. At the beginning of the second half of the 20th century the sporadic maintenance of the castle led to a decline in facade quality and the eventual restoration was very insensitive. Major restoration work was carried out on the facades in 2006 but once this was complete, the renewed facades started to show marked colour inconsistency. This paper analyses the causes of these defects with regard to the technological processes applied and sets out possible steps that can be taken to eliminate them.
Abstract: The need of quality materials for thermal insulation and restoration of building constructions is without question an up-to-date subject. Considering the growing trend in the field of reduction of building construction energy intensity and reduction of CO2 production a general assumption at development of new thermal insulating plasters is the reduction of thermal conductivity and also reduction of density in mature conditions which results in general saving of raw materials necessary for production of 1m3 of applied plaster. Aim of the paper is to acquaint readers with results of research and development of "advanced" thermal insulating plasters obtained within the cooperation of Brno Technology University and Vienna Technical University. Main object of research works was a development of plasters that would show a very good ratio of thermal insulating and mechanical properties, low density, high durability and resistance to humidity and salt influences mainly in case of its possible applications within reconstructions of existing building objects with higher moisture content.
Abstract: The use of lime plaster as a protection of building units against moisture is very common in the monument preservation, but controversially discussed. Historical buildings often demonstrate the problems of the two building materials, in particular the insufficient adherence between clay and lime in the course of time. Previous results of research brought out contradictory statements. The project especially focuses on the compressed, hydrophobic polished lime plaster Tadelakt, which can act as a protection of surfaces in wet rooms with climatically extreme conditions like increased humidity and high temperature. Reported are the results yielded in the research project which covers the investigations to improve the mechanical adherence and to analyze the chemical reaction between the both building materials.
Abstract: Chemical injection of masonry is a very widely-used method for providing supplementary water-proofing of historic masonry. Like all branches of the construction industry, chemical injection of masonry is under pressure to achieve greater performance and speed together with maximum efficiency. Current norms and standards permit both pressure injection and non-pressure injection. Are these methods comparable in efficiency, or should we expect differing effects? A pilot experiment on model masonry pillars has been carried out at the Klokner Institute. This paper summarises the results of our experiments.