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Study of the adheisve affinity into the wood cell wall at the sub-microstructural level
Mitrenga, Ondřej ; Rovnaník, Pavel (referee) ; Vaněrek, Jan (advisor)
This thesis focuses on the problematic of adhesive affinity into wood cell wall at the sub-microstructural level. The main subject of this thesis is research work of scholarly articles focused on the penetration of resins and polymers into the cell wall of the wood. In contains a description of the principles on which the used methods are based, and a summary of the results achieved. In the experiment, several method were used to investigate the possible penetration of selected methods adhesives into the structure of the cell wall. These are fluorescence microscopy, confocal microscopy, scannin electron microscopy (SEM) and transmission electron microscopy (TEM).
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interaction of adhesive with structural wood
Janová, Petra ; Rovnaník, Pavel (referee) ; Vaněrek, Jan (advisor)
This labor is based on penetration of adhesives into a wood cell walls. It focuses mainly on adhesives that are currently used for construction purposes. It also contains a methodics of selecting adhesives and wood, which will be used for glued joints and summarizes the methods used for detect these adhesives in the wood cell wall. It experimentally verifies the appropriate selection of the dye-solvent combination used in the adhesive.
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Optimizing requirements for wood coatings
Bednářová, Ilona ; Petránek, Vít (referee) ; Vaněrek, Jan (advisor)
The work deals with wood coating systems. It is focused on the theoretical division of paints due to different aspects, moreover on testing of wood coating systems. In the practical part of the work, the experimental work regarding the influence of weather conditions onto durability of different wood coatings system was preceded. They were compared two different coatings within the basic tests in different environments.
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Additional reinforcement of wood elements
Janoušek, Radek ; Vejpustek,, Zdeněk (referee) ; Vaněrek, Jan (advisor)
This diploma thesis deals with the possibilities of additional reinforcement of wooden elements using different types of BFRP materials. In the practical part, an experiment of reinforcing plywood with external reinforcement using BFRP fabrics with different basis weights was performed. As part of the strength tests performed, the specimens were subjected to bending and shear stresses. To verify the bonding quality of the plywood, the bodies were exposed to the effect of elevated temperature and a delamination test was performed to determine the bonding quality of the plywood joints. The achieved values were evaluated and compared with the available literature.
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Optimization Of Methodology For Durability Assessment Of Steel Pylons
Čada, Pavel ; Ing. Miroslav. Brodňan, Ph.D. (referee) ; Chobola, Zdeněk (referee) ; Švehla,, Vladimír (referee) ; Vaněrek, Jan (advisor)
In this thesis the corrosion resistance of two types of steel materials were evaluated, Corten A as a representative of WS (weathering steel) and the corrosion resistance of anti-corrosion protection formed by the zinc coating. The different kinetics of corrosive processes was found during the NSS test. WS steel exposed to 400 hours of NSS laboratory test showed growth of the corrosion rate, however, after this period of time there has been a significant decline in this rate. Conversely, when using Zn as anodic protection, the corrosion losses decrease linear up to 300 hours of exposure, but after this time there was a relatively significant linear increase in corrosion rate. During measurements on existing VHV pylons they were measured corrosion decreases of steel and Zn anti-corrosion protection. Normal corrosion rate for weathering steel with 10 m.a-1 and for Zn corrosion loss 1.8 m.a-1 were found. Technical and economic assessment were evaluated using variant of new poles with Zn surface layer and revitalization of existing pylons from WS steel. With regard to all aspects obtained from laboratory tests and economic assessments, friendlier version of revitalization of existing VHV pylons from WS steel using a sufficient corrosion resistance of these steels were found out.
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Study of the interphase region of wood bonds
Chlup, David ; Dufka, Amos (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis deals with summarizing knowledge on issues related to the penetration depth of the adhesive into the wood structure. In the thesis they are described all adhesion theories. We focus on the effect of viscosity and durability bond line according to varying amounts of filler adhesive. Furthermore, it is described some microscopic techniques, which measure the penetration of the adhesive into the cell structure.
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Monitoring and Analysis of Corrosion of Reinforcing Steel in Reinforced Concrete Elements and Structures Using the Acoustic Methods
Timčaková, Kristýna ; Semerák,, Petr (referee) ; Medveď,, Igor (referee) ; Vaněrek, Jan (referee) ; Chobola, Zdeněk (advisor)
The dissertation thesis deals with the study of non-destructive acoustic methods as instruments for monitoring and analysing corrosion of reinforcing steel in reinforced concrete elements. Four acoustic methods were selected for this task - the impact-echo method, the nonlinear acoustic spectroscopy method, the acoustic emission method, and the ultrasonic pulse velocity method. To verify the functionality of these methods, testing was carried out on three sets of reinforced concrete samples that had been exposed to the effects of sodium chloride, which corroded the embedded steel reinforcement in these samples. Suitable parameters were proposed for individual acoustic methods to monitor corrosion of the reinforcements. In addition, experiments were designed to demonstrate the ability of the selected acoustic methods to reveal the corrosion of steel reinforcement and its influence on the concrete matrix and to assess the condition of the degraded elements and structures. The analysis of the measurement results based on their comparison shows the advantages and disadvantages of the individual methods and of their practical applications. To verify the results, correlation with common methods that are currently used for the study of corrosion was carried out and included for example the electrical resistivity measurement of the reinforcement and simultaneous monitoring of the sample surface using a confocal microscope to record the development of microcracks during the degradation.
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Study of thermal resistance of reinforced wood members
Janoušek, Radek ; Krbila, Jaromír (referee) ; Vaněrek, Jan (advisor)
This bachelor's thesis studies the problem of thermal resistance of a system consisting of timber as a structural member with external strengthening in the form of carbon fibre reinforced polymer lamellas connected by various types of adhesives. Attention will be paid to the thermal resistance of reinforced timber members with subsequent mechanical load.
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Modification of epoxy resin effecting ductility of wood bonds
Hudečková, Petra ; Drochytka, Rostislav (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis is focus on a jointing process of wood parts, the basic kinds of adhesives that are used for wood constructions, and also deals with an important demands on a bonded wood joint. Then there is briefly described an issue of fracture toughness and the ways of epoxy adhesives filling, primarily filling with the rubber, the thermoplastics and other fillers. In the experimental part the reinforcing of epoxy matrix with the different quantity of rubber was carried out. The mixture was prepared by an ultrasound homogenizer. Firstly, the tensile strength test with epoxy samples was carried out. Secondly, the Young modulus was calculated and in the last part the fracture surface was analyzed with the scanning electron microscope.
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