Abstract: Originally open balconies and loggias of high-rise residential building showed a significant aerodynamic load - discomfort for users. Subject of the contract cooperation with the investor was therefore development, experimental verification and optimization of the strength and functional parameters of sliding elements of transparent loggia enclosures from the effect of the dynamically changing wind pressure (pressure - suction), as well as the elimination of undesirable acoustic expressions. This paper introduces the aerodynamic study of the building with the objective of quantifying the maximum load on sliding elements from the effects of wind as the boundary condition for their dimensioning. It describes the final design of transparent sliding elements and their experimental verification in a large pressure chamber in laboratory. The elimination of undesirable acoustic expressions was successfully implemented through design optimization with use of acoustic camera.
Abstract: In the present, global production of magnesium oxide (MgO) boards comes exclusively from China. However, Slovakia is one of the leading countries in the mining of magnesite. Therefore, an experiment of MgO board preparation from local resources was realized. The experimental board was made from the calcined magnesite mined out in Hačava in Eastern Slovakia. The paper describes the production process of the MgO board in laboratory conditions. In order to compare the experimental MgO board with a MgO board from China, the tensile strength in bending was examined. The experiment demonstrates that the tensile strength of the experimental MgO board in bending in one direction is higher than the declared strength of the commercial board, but in the second direction it is nearly a half of the declared strength of the commercial MgO board. The results of this paper confirm the potential of the MgO board production from local resources.
Abstract: This contribution is dedicated to an alternative solution of wooden window structure in order to achieve better thermal properties. The proposed window with a sandwich material composition will conform to the requirement of the norm STN 730540 valid from the year 2016. Subsequently, production technology of the given structure will be described.
Abstract: In this paper, the lightweight concrete made from polystyrene and ethylene vinyl acetate (EVA) waste was studied. EVA waste from footwear industry and waste polystyrene were used as an aggregate in the lightweight concrete. Each of the plastic wastes was used alone (as a sole aggregate) or in combination with the other in a ratio of 1:3, 1:1 and 3:1. The water-cement ratio of 0.50 and the dose of cement – 175 kg·m-3 were used for all mixtures. Test results showed that the bulk density and the thermal conductivity of lightweight concrete tended to increase with increasing EVA waste content. The maximum compressive strength of lightweight concrete was reached with the waste materials in a ratio of 1:1. Based on the results, the application of EVA waste as lightweight filler showed a good possibility for use in the lightweight concrete.
Abstract: Epoxy coatings are used mainly in the construction especially where it is necessary to increase the resistance of concrete floors against mechanical wear, to increase chemical resistance, to prevent dusting and to ensure hygienically clean environment. Epoxy coating is a composite material that consists of epoxy resin cured mainly by polyamine hardener and filler. As a filler is currently used pure silica sand Dorsilit ground to below 0.063 mm and for more demanding applications fine glass flakes with a high proportion of SiO2. The aim of this work is to experimentally examine the possibility of using secondary raw materials as fillers into three types of polymer epoxy coatings, where it seems the most appropriate utilization is waste glass with a high content of SiO2. Based on the evaluation of the test results of tensile properties, Shore hardness and temperature resistance the possibility of replacing the commonly used filler by finely ground waste glass is assessed.
Abstract: The development of lightweight thermal insulation plasters containing alternative binders as a partial cement substitute opens the possibilities of using new, eco-friendly materials in civil engineering. The substitution of cement significantly reduces the energy consumption these materials’ manufacturing. In addition, they contribute to the overall energy performance of buildings, which represents another environmental benefit. Concerning the negative effect moisture has on the thermal insulation properties of plasters, the investigation focused on the influence of various hydrophobic agents on the hygrothermal behaviour of the newly developed porous materials. The goal of the research was to develop eco-friendly thermal insulation and rehabilitation silicate materials and to analyse their moisture transport.
Abstract: Properties of building materials used for the construction of surrounding structures significantly contribute to creating a healthy and comfortable microclimate inside the rooms. Ceramics belong among materials which exhibit very suitable properties for the formation of the healthy environment. It is also one of the reasons that the fired clay structures remain popular among builders and that recovery of ceramic prefabrication can be seen in the Czech Republic. The important step towards rediscovering the benefits of the prefabricated ceramic elements is forthcoming production of unreinforced ceramic wall panels made of fired clay masonry units with tongue and groove, connected in the bed joints by two-component adhesives. Conventional analytical model for vertical loads is used in the operating state. However, in the transport and mounting state it is a structure stressed by bending in its own plane. This paper is focused on the issue of load-bearing capacity of structures with masonry units cross-sections that are not filled in head joints and therefore are unable to transfer either tensile or compressive stresses. On the segment of the wall panel is performed numerical model analysis using the finite element method in the computing program ANSYS and comparison of this analysis results with the results of the experimental tests.
Abstract: The prefabricated roller blind lintels have become common solution, particularly for the single-leaf masonry structures without external thermal insulation system. These lintels, representing simple system solution, are designed to interrupt thermal bridges in a place of above the window lintel and simultaneously to provide sufficient reliability of load transfer. The actual outdoor blinds contribute to increase the thermal stability in the room in summer and winter season. They prevent overheating of the room in the summer months and reduce heat transmission through a window in the winter. This paper is focused on the design and numerical modelling of the prefabricated roller blind carrier lintels solutions. Methods of elimination of the thermal bridge are demonstrated on the example of a real produced prefabricated lintel. At the same time this paper deals with its structural analysis. Analyses were carried out using the method of numerical modelling, using finite element method and computing software ANSYS.
Abstract: Slag mortars belong to the new promising alternative construction materials. Conventional cementitious materials are harder to measure by electrical test methods. It is being researched if the dopant atoms in the form of powder improve the mechanical properties. This article describes how the test slag mortars with addition of carbon by electrical impedance spectroscopy measurement methods and their extensions in the form of using ZNC vector analyzer with a coaxial probe from Speag. Impedance spectra of samples were obtained in the 40 Hz to 1 MHz. Declines of impedance by adding more carbon were expected and confirmed. Electrical conductivity and permittivity were measured by vector analyzer for the 100 MHz to 3 GHz. The permittivity was varied from 4 to 20, depending on the addition of carbon, the conductivity of the samples from 1/2600 to 0.3 S·m-1.