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Biodegradation of 3D printed composites based on poly(3-hydroxybutyrate)
Gazdová, Nikol ; Menčík, Přemysl (referee) ; Melčová, Veronika (advisor)
This bachelor thesis deals with the biodegradation of 3D printed bodies composed of poly(3- hyroxybutyrate), polylactic acid, bioceramics and plasticizer. These components were selected for their biocompatibility and properties that could be used in tissue engineering as a temporary, absorbable bone tissue replacement. The main objective was to investigate the effect of the individual constituent bodies on the biodegradation itself. Biodegradation was carried out at 37 °C in a solution simulating the ionic concentration of blood plasma. Samples were sequentially withdrawn at monthly intervals for five months. To evaluate the results, 2 methods were used, weight change and compression test, where the strength of each body was evaluated. From the evaluation of the data it was not possible to reach a uniform result on which substance influences biodegradation the most, because it always depended on the ratio of the other substances. To investigate the effect of poly(3-hydroxybutyrate) and polylactic acid on the rate of biodegradation, mixtures of RP9, RP10 and RP15 were compared. It showed that a higher polylactic acid and lower poly(3-hydroxybutyrate) content had a significant positive effect on the biodegradation rate, as the difference between the weight loss for the RP9 blend with the highest poly(3-hydroxybutyrate) content and the RP10 blend with the highest polylactic acid content was 8.37% for solid bodies and 4.13% for porous bodies. For strength, the difference was 73.32% and 73.65% for the solid and porous bodies, respectively. Observing the effect of bioceramic content on the RP11, RP12 and RP15 mixtures, we concluded that this effect was almost negligible on the biodegradation rate The difference in weight loss between the RP11 mixture with the lowest bioceramic content and the RP12 mixture with the highest bioceramic content was only 1, 68 % for solid bodies and 0.99 % for porous bodies, while mixture RP15 showed the highest biodegradation rate despite having a medium value of bioceramics in the mixture. For the mechanical properties, this then amounts to a difference of 10.4% for the solids and 7.57% for the porous bodies. When comparing the effect of plasticizer for mixes RP13, RP14 and RP15, the effect was more on the strength drop, where the difference in strength drop for mix RP13 with the lowest plasticizer content and RP14 with the highest plasticizer content was different by 20.3% and 18.16% for the solid and porous body, respectively. The decrease in weight was then different by 4.1 % and 0.83 % for the solid and porous body, respectively. Finally, bioceramics from different companies emerged as an important element for the biodegradation rate. Hydroxyapatite from Applichem was the best biodegraded and hydroxyapatite from CN Lab was the worst. The difference for weight loss was 17.35% for the solid and 5.93% for the porous body. The strength loss was then different by 55.6% for the solid body and 33.38% for the porous body.
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Utilization of waste glass in cement composites
Gottwaldová, Aneta ; Dufka, Amos (referee) ; Bodnárová, Lenka (advisor)
Bachelor thesis deals with the processing of waste glass in cement composites. Bachelor thesis includes a search theoretical and experimental part. Specifically, it was verified by fluorescent waste glass and glass screen at a dose of 5, 10, 15 and 20 weight % of a batch of cement. Properties of composites were examined after 7, 28, 56 and 90 days. We monitored TG analysis and XRD analysis of cement composites with waste glass.
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Development of concrete with high fly ash content and verification of durability in various environments
Ambruz, Pavel ; Voves, Jiří (referee) ; Hela, Rudolf (advisor)
This thesis contains two main parts: theoretical and experimental. The theoretical part deals with summarization knowledge of high-volume fly ash (HVFA) concretes. Among others, there are mentioned processes of producing of fly ash, characteristic features and resistance to aggressive environments of HVFA concretes. The theoretical part ends with a suitable example of practical application. In the practical part were tested properties of nine different mixtures containing 40%, 50% and 60% replacement by weight of the cement by fly ash. They were compared with the reference mixtures without fly ash addition. The main endpoints were long-term compressive strength, resistance to aggressive environments, the influence of fly ash on consistency, hydratation temperatures, water absorption and volume changes.
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The utilization of the asphalt and concrete recycled materials to roads
Žďára, Zbyněk ; Šperka, Pavel (referee) ; Stehlík, Dušan (advisor)
This diploma thesis is divided into two parts, theoretical and practical. The is a review om the topic of recycled asphalt pavement and recycled concrete and their possible use in road construction in the theoretical part. The individual chapters deal with describing these materials, their production, and their use in construction layers of pavements. In the next chapters the attention is also paid to their problematic features and foreign experience using these materials in pavements. In the practical part, laboratory samples of recycled asphalt pavement and recycled concrete and their mixtures with cement are tested. The main purpose is to verify the applications of these mixtures of recycled asphalt pavement and recycled concrete in the bonded base layers of the pavement. Another purpose is to compare how these mixtures individual properties with different proportions of both components and different amounts of cement will be different. In the end, the two mixtures with the best properties was selected and the modulus of elasticity was experimentally determined for the possibility of replacing the currently used base layers and the economic evaluation of this design was made.
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The Influence of different Types of Fiber-reinforcement on the Behavior of Concrete Slabs
Wünsche, Dominik ; Žítt, Petr (referee) ; Kocáb, Dalibor (advisor)
The bachelor‘s thesis deals with the issue of concrete, specifically self-compacting concrete, fiber concrete and other types of concrete used. The work consists of two parts, the theoretical one, which will deal with the properties of the concrete. It describes the individual test methods used in the practical part. The test methods are the ultrasonic pulse method, the resonance method, the static modulus of elasticity, the compressive strength, and especially flexural strength. The second part is a practical part, which is processed by an experiment. In the experimental part, it will be mainly about carrying out tests of self-compacting concrete slabs and concrete with the addition of steel fibers. Subsequently, selected characteristics of concrete are determined and the whole experiment is evaluated.
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The development of high-strength concrete with a high content of el. fly ash
Roubal, David ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the study of high-strength, high-volume fly ash concrete. The theoretical part of this thesis focuses on the detailed characteristic and main principles of high-strength concrete, high-volume fly ash concrete. In addition, according to the findings, the technology of high-strength and high-volume fly ash concrete, including principles of high strength, has been described. On the basis of the findings, high-strength, high-volume fly ash concrete for specific compressive strengths has been designed and created in the experimental section. These concretes were then subjected to a number of tests.
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Comparison of selected parameters of tensile strength of concrete
Rozsypalová, Iva ; Žítt, Petr (referee) ; Daněk, Petr (advisor)
The thesis deals with a comparison of the selected strength tension properties of the hardened concrete and finding relationships between them. This is essentially a simple tensile strength, tensile flexural strength and tensile splitting strength. The text describe the testing procedures to determine the tensile strength of concrete. Furthermore, there are presented the results of testing on different types of concrete (plain concrete, lightweight concrete, steel-fiber concrete, polymer-fibre concrete and high strength concrete). The conclusion deals with the derivation of dependancy between concrete strengths and comparing the values obtained from the available relations with the results of the tests.
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Suitability of vitrified lignite bottom ash for composite cements.
Bayer, Petr ; Krátký, Josef (referee) ; Wolter, Albrecht (advisor)
Předložená magisterská práce se zabývá možným použitím vitrifikovaného lignitového lóžového popele jako náhrada slinku v kompozitních cementech. Byly zkoumány vlivy přidaného vitrifikovaného lóžového popele, jeho jemnosti, alkalických roztoků a jejich koncentrací. Byly připraveny kompozitní cementy v souladu s normou DIN EN 197 – 1. V těchto cementech bylo nahrazeno 30 % slinku vitrifikovaným lóžovým popelem. Konkrétně byly připraveny kompozitní cementy s vitrifikovaným lóžovým popelem o jemnosti 5549 cm2/g a 8397 cm2/g. Dále byly přidány alkalické roztoky hydroxidů a síranů vždy o dvou různých koncentracích, za účelem stimulace pucolánové a/nebo geopolymerní reakce. Mechanické vlastnosti připravených vzorků byly charakterizovány mechanickým testováním na prizmách s rozměry 40×40×160 mm, jak je specifikováno v normě DIN EN 196 – 1. Byla provedena nedestruktivní měření dynamického elastického modulu a destruktivní testovaní na pevnosti v tlaku a v ohybu. Distribuce velikosti částic a chemická analýza vstupních materiálů byla vykonána pomocí laserové granulometrie a rentgenové fluorescence. U zatvrdlých kompozitů bylo dále zkoumáno po 2 a 28 dnech hydratace fázové složení s využitím metody rentgenové difrakce a mikrostruktura s využitím skenovací elektronové mikroskopie. Výsledky ukázaly, že mechanické vlastnosti jsou nezávislé na množství přidaných alkálií stejně jako na jemnosti přidaného vitrifikovaného lóžového popele. Nicméně, znatelně nižší mechanické pevnosti byly pozorovány pro vzorky, které byly aktivovány hydroxidy, pravděpodobně kvůli brzké tvorbě silikátového hydrogelu. Vzorky aktivované sírany nedosáhly pevností jako referenční malta.
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The development of ultra-high strength (UHPC) and reactive powder (RPC) composites
Rundt, Lukáš ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Bachelor’s thesis studies ultra-high strength concrete and reactive powder composites. In theoretical part there are researched and described properties of raw materials used for their production, mainly additions. Design methodology, processing and types of curing are also studied. Psychical mechanic and durability properties of fresh and hardened concrete are described. In practical part 4 mixtures were designed and prepared and their rheological properties, strengths after 7 and 90 days in case of UHPC and strengths after 7, 28 and 60 days in case of RPC were tested.
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