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Wood stabilizers for its use in cement composites
Vaněk, Dominik ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The thesis focuses on the analysis of the effects of wood stabilizers in wood cement composites. Moisture, dimensional, thermal and mechanical parameters of wood cementitious materials were monitored. In addition, the effect of replacing cement with alternative components was also assessed. Within the theoretical part, a survey of the literature findings is made with a focus on the stabilization of wood in these composites. The theoretical knowledge was evaluated and subsequently the types and concentrations of stabilizers or modifiers were proposed for the experimental part of the work. In the experimental part, the effect of stabilizers on selected wood parameters was first analyzed. Next, the hydration parameters of the individually stabilized wood-cement mixtures were assessed. These parameters were evaluated and then the formulations of the wood cement mixtures from which the cement-bonded particleboards were made were proposed. Selected mechanical properties were determined on these boards, which were evaluated and assessed including microstructural analysis.
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Long-term tests for examination of surface treatments in various adverse environments simulating real effects
Hudečková, Petra ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
Cement bonded particleboards contain organic base and as they are set outside, extreme weather condition, such as frost, chemical defrosting substances or sulphates, cause their degradation. The presence of the organic base in the matrix of the material could be the reason why there is higher probability of degrading when compared with materials containing an inorganic base. It could be partially eliminated by an appropriate surface modification of the slab, which main goal is to weaken the impact of an aggressive environment and to extend the lifespan of the board. On the other hand, the surface modifications based on a polymer base are prone to degrade because of other unfavourable conditions such as UV radiation when compared with the cement bonded particleboard. The classification of the surface modifications and the way of their degradation caused by the aggressive environment in real applications are presented in the theoretical part of the thesis. In the experimental part, appropriate methodical ways of testing the resistance of cement bonded particleboard’s coating system were chosen. Then, the testing and comparing of the physical, mechanical and aesthetic properties of different types of coatings were done. Moreover, a spectrophotometric analysis of the colour shade changes for the different aggressive environment were carried out. Furthermore, microstructures of chosen surface modifications were assessed by using an optical and an electron microscope.
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Modification of the filler in cement-bonded boards with alternative filamentous fillers
Dywor, Michal ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The cement boards are commonly used as a filler fir or spruce chips-profit wood. The increasing demands for construction materials forcing technology to develop new types of composite materials using an alternative source of fillers. In this work in the context of theoretical knowledge about the specified fibers in composite systems are discussed properties of cement binder and filler for cement – bonded particleboards and alternative materials. The practical part describes the test methods designed recipes and then made boards of which were carved specimens intended for testing the properties of boards with alternative fillers.
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Cement-bonded particleboards with utilization of alternative raw materials
Urbánek, Libor ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis is focused on effective utilization of currently produced alternative raw materials in the production of cement-bonded boards. The emphasis is primarily on the scraps and dust arising from the processing of cement-bonded slabs, as well as on slag and limestone. The theoretical part contains a survey of current knowledge about the given issue. In the experimental part, the alternative raw materials were analyzed in detail and their influence (as modifier components of the matrix and the filler) on the properties of cement-bonded slabs was examined. Research and development took place using physico-mechanical, thermal and microstructural methods.
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Optimisation of cement-bonded particleboard matrix composition by using alternative raw material sources
Roháček, Lukáš ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis deals with possibility of utilization raw materials from alternative sources for production of cement-bonded particleboards. In theoretical part the possibilities of modifying composition of cement-bonded slabs with emphasis on their matrix are discussed in detail. On basis of the findings and their evaluation, waste from the formatting of cement-bonded particleboards, micronized limestone, heat sink and high temperature fly ash were selected to the composition modification. The mentioned raw materials were analyzed and subsequently tested as substitutes for the matrix of cement-bonded particleboards in the experimental part. The properties of the proposed materials were tested even in the longer term, including the microstructure.
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Development of cement-bonded particleboards with modified matrix composition
Konečný, Dalibor ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
In manufacture of cement-bonded particle boards are in present-days used exclusively wooden particles as filler. This thesis deals with a research of possible substitution of this material, especially of waste emerging by production of CBPB itself. At first is completed a survey of possible substitute fillers and czech and foreign literature, dealing with issues of modification of composition of cement-bonded particle boards. In practical part are tested some treatments of waste and its adding to recipe. Further are analysed the influences of substitution of cement by slag and substitution of wooden particles by recycled fibreglass. By laboratory work with CBPB is monitored the influence of amounts of added wather to fresh mixture and also to properties of finished elements.
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