Abstract: Natural and artificial wooden mineralization leads to mineral particles deposition which positively affects certain properties. An evaluation of mineral content is therefore important. This study is focused on the application of thermal analysis for quantification of mineral content in surface wooden layers. Suitability of methodology used for specimen preparation and testing, and also derived relationships are confirmed by the example of artificial mineralized wood by organosilane.
Abstract: Wooden construction elements are exposed to many degradation factors during their use that result in structural changes. Structural changes, such as mineral particle depositions, also occur in contact with mineral solutions, which is typical for wooden elements that are partly or completely infiltrated by mine water. In this article, a mine timbering obtained from historical mining galleries in the area of Zlaté Hory is examined to verify specimen authenticity based on mineralization quantification by thermal analysis.
Abstract: Building structures have been designed such that they are able to withstand the adverse effects of the environment for a certain time. The terms "for a certain time" and "the surrounding environment" are used for a purpose here, and that is because the phenomenon of ageing buildings is currently an increasingly discussed problem that is faced by every larger city. The materials used in the buildings, such as façade cladding, age just as the buildings themselves do. An immense pressure has been currently put on designers to use environmentally friendly materials not only for new buildings but also for the retrofitting of existing ones. The aim of this paper is to demonstrate that wood or wood composite materials are convenient solution for restoration of façades of administrative or commercial buildings, however, since the new cladding have to be connected with an old load-bearing structure, the designers have to overcome many limitations. One of the main difficulties is high thermal and moisture expansion of these materials which has a direct impact on the appearance of the façade. The obtained results showed that expansion properties should be studied closely when using wooden elements in the design and that a neglection can lead to a premature failure of the system.
Abstract: This article is oriented toward the heat-moisture behaviour of the wooden construction sheeting. The behaviour of building envelope is evaluated according to the heat transfer coefficient and foremost from the view of the condensed vapour amount inside the building envelope structure. For exemplary building envelope will be elaborated model calculations and then they will be compared. The results have shown that diffusion-open structure has the best characteristics concerning the heat-humidity behaviour and ecology of wooden constructions.
Abstract: The known solution of isotropic elastic layer was modified for orthotropic elastic material behavior in this contribution. The solution was original derived for calculation of footing settlement. However it should be useful for estimation of orthotropic material parameters. Timber is classical orthotropic material. Timber board which is placed on the rigid basement it could be considered as the elastic layer. From the known load displacement curve we can, vice versa, estimate the material parameters. The present solution should be able to control loading by rigid strip footing acting perpendicular to the plane of orthotropy. The contribution summarize the first steps of the proposed back analysis.
Abstract: This paper deals with the influence of the coarse aggregate grain size on the frost resistance of concrete. For the purpose of the experiment, three types of concrete were produced, varying only in the maximum grain size of the used natural aggregate. The evaluation of the frost resistance of concrete is based on non-destructive (NDT) dynamic and static testing methods. The results of the experiment indicate influences of the aggregate used in the production of the concrete on the results of its frost resistance.
Abstract: The paper reacts to the contemporary situation in the field of determining the position of reinforcement in the reinforced concrete structures, in which the best method used so far – the Co 60 radiography – is significantly limited or even excluded due to the tightening of laws and regulations for management of radiation sources. In the article, the authors focus on the use of alternative NDT methods which, in an appropriate combination, can substitute the present radiographic method. They mention the advantages as well as technological and principle limitations of the methods of georadar and electromagnetic indicators, and on practical examples they demonstrate their usability when used separately or in a suitable combination.
Abstract: This paper aims to verify the use of recycled foam plastics to produce lightweight concrete. Two types of recycled foam plastics (ethyl vinyl acetate and cable insulator) and their mixture in ratios 3:1, 1:1 and 1:3 were used as filler. An organic-based adhesive, Conipur 360, was used as a binder. The evaluation method included verify one of basic physical properties – bulk density. At the same time, thermal properties and strength characteristics of the samples were monitored.
Abstract: The paper deals with the experimental investigation aimed at the continual monitoring of the process of setting and early hardening in cement pastes and mortars using the measurement equipment Vikasonic. The measurement principle consists in measuring the time of ultrasonic pulses transit through a test specimen placed between two ultrasonic transducers. This innovative method of measurement could in the future suitably complement or, in some cases, completely substitute the measurement of setting in cement composites using the Vicat apparatus. The pilot measurement results performed on the cement pastes and mortars are presented in the paper.