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Modelling of shear strength of concrete beams
Večeře, Jakub ; Lehký, David (referee) ; Novák, Drahomír (advisor)
The bachelor thesis deals with the modeling of reinforced concrete beams and compares their load-deflection (L-D) curves with curves obtained in an extensive experiment at the University of Lodz under the guidance of Prof. Renata Kotynia, Dr.Hab. For comparison, data from two selected beams with identical shapes, lengths, and concrete strengths were used – one reinforced with steel and the other with a composite made of glass fiber-reinforced polymer (GFRP). Modeling is carried out using nonlinear fracture mechanics of finite elements (2D) in the ATENA software. Emphasis is particularly placed on accurately modeling the bond between concrete and reinforcement. Modeling was performed in both 2D and 3D.
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Design of repair material with reduced electrical impedance
Žáková, Karolina ; Černý, Vít (referee) ; Drochytka, Rostislav (advisor)
This bachelor's thesis focuses on designing a new composition of corrective material based on silicate with the aim of reducing electrical impedance. In the theoretical part, fundamental concepts necessary for understanding the topic will be described, such as terms related to conductivity, silicates, composites, and corrective materials in general. The experimental section includes the selection of raw materials, preparation, and testing of various compositions of corrective materials with different fillers. The impact of various additives on the electrical properties of the corrective material will be investigated, including its conductivity, resistivity, and cohesion. The final section summarizes and evaluates the achieved results.
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Evaluative Language in Electronic Product Reviews
Polášek, Radek ; Mihai, Hana (referee) ; Reich, Pavel (advisor)
Tato práce bude zaměřena na ohodnocení jazyka v recenzích mobilních telefonů. K tomuto účelu bude použita recenze Apple iPhone 7. Apple má širokou nabídku produktů, jmenujme počítače, tablety, hodinky nebo mp3 přehrávače. Mobilní telefony jsou ale jedním z nejpopulárnějších produktů. Z tohoto důvodu, jsou recenze mobilních telefonů perfektním zdrojem pro tuto tezi. Účel této práce je analyzovat a demonstrovat prostředky ohodnocení jazyka v reklamní mluvě a odhalení strategií a jazykových prostředků použitých k ovlivnění čtenáře, při apelování na city, morálku a estetiku chápání. Předpokládám, že recenze jsou zaujaté díky použité formě jazyka, která může obsahovat osobní názory autora nebo metody manupulace se čtenářem. Tyto metody mohou být použity při stylizaci textu, mohou apelovat na emoce nebo sociální zázemí čtenáře nebo mohuu být použity při rozhodování o tom zda a jaké informace v recenzi poskytnout. Tato teze ověří, zda je tato hypotéza platná.
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Use of FRP Composites as Reinforcing Material for Concrete
Kratochvílová, Denisa ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
Because FRP composites have high fiber strength and good durability, they are increasingly used for repairs, modernisation and reconstruction of concrete structures. In practice, however there is a risk of premature separation of FRP reinforcement from concrete. This can be avoided by appropriate selecting the fibers and the matrix and the appropriate shape of the reinforcement. The actual materials and consistency of FRP reinforcement with concrete are also covered by this diploma thesis.
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Static analysis of a concrete outlet channel
Skalník, Stanislav ; Nováček, Jan (referee) ; Zich, Miloš (advisor)
The thesis deals with the static analysis associated with the outlet channel of the lock chamber. The basis for the work was the design of reinforcement using full-threaded prestressing bars and the drawing documentation of the existing condition. The aim of the work was to present the issues associated with the anchoring of the prestressing bars by cohesion in the existing concrete structure, in particular testing on test blocks in the laboratory to verify a suitable solution. Following the data obtained, to perform an analysis and comparison on models solved by nonlinear computation in ATENA Science software. Subsequently, the analysis of the model of the existing condition of the outlet channel section is also carried out by nonlinear calculation with the evaluation of its behaviour to extreme loads. This model is then supplemented with reinforcement using prestressing bars with application of the knowledge associated with the pullout test models. The model of the pre-stressed outlet channel section is thus a simulation of the design on the lock itself.
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Structural Properties of Ultralight Concrete and its Optimal Application in Structures
Kadlec, Jaroslav ; Bílek,, Vlastimil (referee) ; Adámek, Jiří (referee) ; Terzijski, Ivailo (advisor)
This doctoral thesis deals with design of three variants of ultra lightweight concrete (ULC) and their mechanical properties. The ULC usually has the dry density of 900-1200 kg/m3 and it is possible to use it for load bearing structures. Low density of ULC is achieved by replacing heavy aggregate for lightweight aggregate. The lightweight aggregate is known under the trade name Liapor in the Czech Republic. To achieve density below 1000 kg/m3, an aeration of the paste has to be done. An exchange of heavy aggregate for lightweight aggregate results in a very fragile behavior of ULC. A great attention is paid to bond strength between concrete and reinforcing steel in the thesis. In addition to the standard test of bond strength testing by pull-out, a modified pull-out test is designed, which includes the effect of minimum reinforcement cover. The mentioned test more precisely simulates a real behaviour of the structure exposed to bending moment. The doctoral thesis tries to point out on different parameters between measured data and the applicable standard for the design of load-bearing structures.
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Adhesion of Adhesive Joints for Facade Applications Made of Wood-based Materials
Nečasová, Barbora ; Schmid, Pavel (referee) ; Sedlák,, Petr (referee) ; Kovářová, Barbora (advisor)
The presented dissertation thesis is focused on investigating the adhesive properties of façade cladding made of wood and wood-based materials in combination with flexible adhesion/assembly systems. The systems allow the implementation of effective construction joints and provide a solution with uniform stress distribution which allows the transfer of heavy loads, while simultaneously reducing the weight of the entire structure, which is also often connected with substantial cost reductions. Despite all that, little attention has been paid to this area so far. It is not a solution which is properly embodied in technical standards or in designers´, architects´ and contractors´ awarenesses. The aim of this dissertation is to characterise adhesive properties of selected façade cladding representatives made of wood and wood-based materials for the purposes of bonded joint application in a ventilated façade system. To define adhesion of façade joints, numerical and experimental methods are used, taking also various limit conditions into account. The main conclusion of the dissertation is the characterisation of basic parameters which influence adhesion, effectiveness and quality of façade glued joints. The secondary conclusion is the compilation of a simple methodical procedure for testing and implementing façade glued joints. The dissertation also makes a contribution by extending the current state of knowledge of façade adhesive joints.
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DEVELOPMENT OF SPECIAL REHABILITATION MATERIALS FOR CONCRETE FOR EXTREME STRESS WITH USE OF SECONDARY RAW MATERIALS
Hodul, Jakub ; Klečka,, Tomáš (referee) ; Ďurica,, Tibor (referee) ; Bydžovský, Jiří (referee) ; Drochytka, Rostislav (advisor)
The doctoral thesis deals with finding the use of some waste and secondary raw materials in the production of special polymer remediation materials for concrete, which could be applied even in constructions, where extreme mechanical and chemical load is occurred. The aim of this doctoral thesis is experimental examination of the possibility of using selected types of waste, including hazardous waste which represent the highest risk to environment, and secondary raw materials as a substitute for the currently used primary fillers in order to reduce the ecological footprint of the product itself. Some types of secondary raw materials, such as filter fly ash contaminated by flue gas denitrification process, are no longer used as a concrete admixture or partial cement substitution due to unwanted release of toxic ammonia (NH3). Mainly for this reason, the thesis deals with the progressive utilization of such types of secondary raw materials as well as with another currently unused waste into polymeric patching, grouting and anchoring materials while preserving or improving the final properties compared to reference materials using only primary raw materials. The result of this thesis is to find out suitable formulations for efficient preparation of special polymeric remediation materials for concrete containing waste and secondary raw materials as fillers. The partial aim of the thesis and a the scientific contribution is an observation of the developed materials internal structure using a modern device, CT tomography, an influence of the filler type on the long-term durability, and last but not least the observation of the rate of pollutants incorporation, found in hazardous waste, into the polymeric matric with the aid of EDX and FTIR analysis.
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FRP for concrete reinforcement
Blahová, Aneta ; Vaněrek, Jan (referee) ; Bodnárová, Lenka (advisor)
The bachelor thesis deals with composite polymer FRP reinforcement. It descibes the method of manufacturing FRP reinforcements, which are their properties and what materials are used by manufacturers. Lists FRP reinforcement application in various structures. Also mentions the durability of FRP reinforcement in an aggressive environment and the cohesiveness of FRP reinforcement with concrete. The conclusion of the work is a proposal for experimental testing of a bond between FRP reinforcement and concrete.
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