Proceedings of the Conference on the Rehabilitation and Reconstruction of Buildings (CRRB 2014)

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Authors: Sylvie Slunská
Abstract: Wood as organic material is extremely stressed and it is surface may be damaged over time due to atmospheric effects, mainly due to solar radiation and exposure to water. The purpose of this experiment is to compare colour changes of selected impregnation stain the wood, which in practice is primarily used for facade systems. These are among some of the most stressed parts of the building and construction, they must be paid great attention. Wood samples were painted with a colour glaze impregnation and subsequently subjected to artificial aging. The results show that the type of selected species, but also finish before applying a waterproofing glaze can affect subsequent changes light fastness whether, it is a lightening or darkening.
Authors: Anastasiia Kravchenko, Sergii Guzii, Yurii Tsapko, Vít Petranek
Abstract: Was conducted survey of condition and fire-retardant properties of surface of timber constructions, protected by coating on geocement-based, after their operation under atmospheric conditions. For a comprehensive assessment of fire-retardant determined following characteristics: type of corrosive environment; duration of operation of structural elements coated; coating thickness and integrity; cracks; adhesion of the coating to the timber; determination of the fire-retardant properties of the coating. Assessment of the results obtained, despite the significant deterioration in the appearance of geocement-based coating retains its primary function, fire protection, having after one year of operation, – 1 group of combustibility.
Authors: Sergii Guzii, Anastasiia Kravchenko, Pavlо Krivenko, Yurii Tsapko, Konstantinos Sotiriadis
Abstract: In this paper, the application of a heat-reflecting geocement coating, containing perlite, to reduce timber combustibility was studied. An optimized coating composition was prepared, which consisted of a geocement (Na2O·Al2O3·6SiO2·21.5H2O) and expanded perlite (9.5%). The main firing properties of this coating were invastigated. In terms of flammability, the fire protected timber reduces mass loss by 13 times and temperature of combustion gases by 5.2 times compared to unprotected timber. According to standard indicators, the reduction is by 1.3 and 10 times, respectively. The smoke generation of fire protected timber was decreased by 4.9 times (combustion mode) and 3.8 times (smoldering mode) in comparison to the unprotected timber. According to standard indicators, the decrease is by 4.5 and 2.3 times for each mode, respectively. The index of flame spread and the combustion rate reduced by 20.3 and 6.3 times, respectively, in the case of the fire protected timber compared to the unprotected one. The pine timber protected by heat-reflecting fireproofing geocement based coating, which contains perlite, refers to flame-retardant materials with moderate smoke generation and with low index of flame spread on the surface.
Authors: Tereza Murínová, Pavel Mec, Jana Daňková, Petr Rezek
Abstract: Moisture characteristics, related durability and especially strength parameters are observed for wood (solid, treated, or modified), which is used in building constructions. Material modification by siliceous substances reduces intake of liquid water, but solution exposition and subsequent deposition of mineral particles may also affect the physico - mechanical properties of the material. In this work, longitudinal compressive strength was determined for the samples treated by dipping in aqueous solution of organosilane. The results confirm the correlation between the length of dipping and the change of tested strength parameter.
Authors: Rostislav Zídek, Aleš Utíkal, Ivana Utíkalová, Luděk Brdečko, Helena Brdečková
Abstract: The paper presents some aspects of the reconstruction of timber roofs at Žehušice Castle. The roofs were built at different times and using various types of structural systems. Many timber elements of the roofs have been heavily damaged by previous unprofessional alterations to them, or, more often, by neglected maintenance and subsequent fungal attack caused by massive leaking. Because of the requirements of the National Heritage Institute it was necessary to be sensitive to the existing structures and minimize changes to them during the reconstruction of the roofs. In order to successfully achieve this, it was necessary to understand the distribution of stresses in the structure and its static behavior as well as possible. Therefore, 3D computational models were developed. On the basis of the obtained results, it was decided whether roof elements would be replaced or only parts of them. However, the informative value of relatively complicated mathematical models appeared to be limited.
Authors: Barbora Nečasová, Pavel Liška, Jiří Šlanhof
Abstract: A research case focused on vented wooden façade system with bonded joints is presented in this paper. The potential of bonded joints is studied and described in more detail and verified through experimental measurements. For the purpose of tests spruce timber profiles were chosen for the load bearing substructure and Siberian larch façade sheeting for the cladding. Three types of industrial adhesives intended for structural bonding were selected. The article is focused on the preparation as well as on the subsequent experimental verification of substructure bonding retention to the cladding. The adhesive bonds were tested both in tension as well as in shear at a temperature of (293.15 ± 3) K and a relative humidity of (55 ± 10) %. The test results proved the fact that bonded joints are more than suitable equivalent to the mechanical joints. During the tests appeared some differences in stability and failure behaviour between the adhesive systems as well as within the sheeting material. Additionally, the suitability of selected group of adhesives in combination with Siberian larch cladding material as well as with the timber substructure was confirmed.
Authors: Nikol Žižková, Patrik Bayer
Abstract: The article focuses on the use of tree types of pozzolanic materials in the production of cement pastes and polymer-modified cement pastes. The determined physical-mechanical parameters of the pastes with pozzolanic materials were compared with a pure cement paste. For polymeric modification, ethylene/vinyl acetate copolymer (EVA) was used, which was added to the mortar and concrete during the preparation to improve some properties such as fracture toughness, impermeability and bond strength to various substrates.
Authors: Jitka Peterková, Jiří Zach, Martin Sedlmajer
Abstract: The paper describes the results of research in the field of thermal insulation plasters suitable for thermal insulation and rehabilitation of historical buildings. The aim was to develop energy-efficient, lightweight plasters, using both common and alternative binders. These were mainly materials based on lime slurry and light porous aggregates that are compatible with the original plaster and masonry materials. These materials are, given their high porosity, capillary active materials and can therefore be used in the restoration of historical buildings, which are often burdened with higher moisture.
Authors: Grigory Yakovlev, Alena Politaeva, Arina Shaybadullina, Anastasiia Gordina, Alexander Buryanov
Abstract: The factors influencing the formation of efflorescence of construction materials are connected with the increased solubility of the ingredients of construction materials. Efflorescence may accumulate under some less permeable decorative paint layers and cause their peeling from the surface of a building structure, its decorative properties being completely lost. At the same time, the formation of efflorescence not only as white bloom, but also as "blooming" of the surfaces of materials due to the formation of new chemical compounds is possible. Similar processes occur in the process of operation of coloured pavers manufactured wth vibrocompression of cement and sand mortars with the addition of colouring pigments. The main source of efflorescence is calcium hydroxide Ca (OH)2 which is formed in hardening cement. The alkaline nature leads to its intensive interaction with carbon dioxide CO2. This efflorescence in the second year of operation, as a rule, does not resume due to the carbonation of calcium hydroxide in the structure of set cement.

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