National Repository of Grey Literature 92 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Studium a vývoj polymer-cementových kompozitů s důrazem na vysoký obsah druhotných surovin a kompenzaci objemových změn
Hermann, Radek ; Bydžovský, Jiří (referee) ; Reitermann, Pavel (referee) ; Kolísko, Jiří (referee) ; Drochytka, Rostislav (advisor)
Reducing of humanity's carbon footprint is currently one of the main directions of global research. Another significant problem is the disposal, recycling and secondary use of waste materials produced from a wide range of industries and municipal waste. This thesis deals with the problematics of polymer-cement composites, which are most often used for rehabilitation, reprofiling and structural repairs, especially of concrete structures. The thesis examines and verifies the possibilities of utilization of a large amount of secondary raw materials and waste as a substitute for cement as a primary binder. At the same time, the work deals with the full replacement of the primary filler with waste raw materials, for which there is currently no other use. The work also addresses and verifies the influence of several commonly available commercial polymer dispersions. The work deals with the use of liquid, but also powdered polymeric additives of various bases. The work also deals with the problematics of volume changes of the hydration process of polymer-cement composites and the effect of volume changes on the physical-mechanical properties of composites. The influence of volume changes that occur during the hydration of polymer-cement composites is a significant criterion in the selection and use of these composites. The volume changes of the material have a great influence especially on the maximum layer thickness and the maximum area that can be repaired with the material without the risk of cracks and the need to create a working joint. The results of this work are associated with a reduction in the economic and environmental impacts of production and use of polymer-cement building materials and increase the usability of these materials mainly due to the possibility of remediation of larger areas than previously possible.
Development of adhesive material for installation of cast basalt elements on metal base
Šikral, Martin ; Hodná, Jana (referee) ; Drochytka, Rostislav (advisor)
The diploma thesis deals with the development of polymeric adhesive material for the installation of cast basalt elements on a metal surface. The aim of this work is a development of the new adhesive material for the fixing of cast basalt elements to a metal base in high chemical stress environment and at higher temperature conditions. Furthermore, the thesis explores the possibility of using secondary raw materials as a substituttion of primary materials in the form of fillers. The thesis is also focuses on the determination of the advanced testing methods to verify the properties of devoloped adhesive materials, including monitoring the microstructure of the contact zone between the adhesive material and the surface.
Development of grounding enhancing cement composite mixture
Sochor, David ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
The diploma thesis deals with the development of a conductive cement composite grounding mixture for protection of building structures in areas with low conductivity. The theoretical part is focused mainly on the methods of buildings protections against lightning and overvoltage. The aim of this is to create a conductive composite with the possible use of secondary raw materials, which have a low electrical impedance value. The conclusion of the thesis is devoted to the evaluation of the efficiency of newly designed conductive composites and their possibility of incorporation into building protection systems against lightning or overvoltage.
Development of chemically resistant tile grout containing secondary raw materials
Matušková, Veronika ; Seidlová,, Michaela (referee) ; Drochytka, Rostislav (advisor)
The aim of the diploma thesis is development and research of a high-quality polymeric jointing grout material using secondary raw materials and hazardous waste for extreme chemical exposure. The main intended use of the developed grout joint is grouting of the cast basalt elements in building objects that are permanently expose to highly aggressive chemical environment. The use of input materials produced by progressive technologies should be another benefit of this grout joint to enhance ecological aspects of a grout joint production.
Development of resistant composite containing secondary raw materials for reconstruction of objects from cast basalt
Čtvrtečková, Anna ; Jakubík, Aleš (referee) ; Drochytka, Rostislav (advisor)
The diploma thesis is focused on the development of the resistant repair composite material using, secondary raw materials for the rehabilitation of objects made off the cast basalt with the highest possible filling of secondary raw materials. The resistant composite shall show the parameters approaching to the properties of cast basalt. The work is also focused at physical and mechanical properties of the composite material and its resistance to chemically aggressive conditions, and it is also aimed at the rehabilitation technology, especially the appropriate pre-treatment of the substrate to provide sufficient cohesion between the substrate and the repair composite.
Žlebek, Tomáš ; Seidlová, Michaela (referee) ; Bydžovský, Jiří (referee) ; Ďurica, Tibor (referee) ; Drochytka, Rostislav (advisor)
The work deals with the development of new polymeric coatings and screeds – epoxy, polyurethane and vinyl ester materials with the use of hazardous waste in the form of fillers. The areas that are destined for their landfill are constantly expanding and the costs of disposing of this waste are high. Their use eliminates negative impacts on the environment, but also leads to significant financial savings. The aim of this PhD thesis was to find a suitable way to treat selected hazardous waste and experimentally verify the possibilities of using the fillers pre-treated by optimal way in polymer coatings and screeds. The coatings and screeds are intended primarily for concrete substrates but the possibility of use on metal substrates, asphalt and cement-bonded particle boards was also been verified. These materials serve as a secondary protection of structures against the adverse effects of weather conditions. Secondary raw materials were used as fillers, which were fluidized bed combustion fly ash contaminated due to flue gas denitrification and specially pre-treated hazardous waste (solidification products). The aim was to proceed progressive use of the secondary raw materials as much as possible in order to reduce landfilling in the maximum possible way. It was necessary to treat hazardous waste in such a way that the most effective solidification would be achieved. The behavior of the solidifaction products in the polymer matrix, the distribution of particles in the structure and the disruption of coatings and screeds due to chemical stress were also investigated.
Study of the influence of structure on the resistivity of silicate composites
Uher, Vojtěch ; Šteffan,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Electroconductive silicate-based composites are advanced materials that allow building structures to perform several different functions simultaneously. Addressing the issues of their development and use is a suitable topic for research work. The aim of this work is to study the effect of structure on the resistivity of silicate composite. The structure of electrically conductive composites is studied on dry cement paste and mortar mixtures as well as on test bodies made of hardened cement paste and mortar after 28 days of curing. Based on the analysis of the raw materials, six suitable electroconductive fillers are selected based on particle size, resistivity, and water absorption. The parameters of dry cement paste and hardened cement paste with replacement of 4-19 wt. % cement by the selected fillers are determined. Two of the fillers are selected for use in dry and hardened mortar. Resistivity is determined for all dry mixes and hardened composites variants, and percolation thresholds are approximately determined. By studying the structure of the selected variants, it is shown that the most important parameters that have the greatest influence on the resistivity of the silicate composites are mainly the particle size and the intrinsic resistivity of the electrically conductive filler. For silicate composites in the hardened state, the volume of hydration products, especially portlandite and C-S-H gels, also has a significant influence. For both dry blends and hardened composites, it was found that the smaller the particle size of the electroconductive filler, the smaller the representation needed to reach the percolation threshold. Portlandite and C-S-H gels in the volume of the hardened composite cause its high resistivity. The resistivity of the hardened composite is always higher than that of the dry blends. Thus, the proportion of electroconductive filler needed to reach the percolation threshold is higher in hardened composites than in dry mixes. The resist
New possibilities of using secondary raw materials for the renewal of the railway substructure
Buřičová, Karolína ; Luňáček,, Martin (referee) ; Drochytka, Rostislav (advisor)
The work is devoted to new possibilities for the recovery of secondary raw materials and track bed waste with a combination of both suitable and unsuitable soils. The aim of the thesis is to develop a new functional sample suitable for the recovery of a substructure of railways based on secondary raw materials. The theoretical part addresses the issue of the use of soil and secondary raw materials as the base layers of railway structures, and is focused on the possibilities of soil adjustments or enhancement. The practical part is focused on the analysis and selection of potentially suitable raw materials, the design of new raw material mixtures containing concrete recyclables, waste from cleaning the auto mixer and waste from cleaning the rail bed. Further, to modify the mixtures designed with fluid ash from biomass combustion to achieve higher toughness. Then they will be experimentally verified and based on the results the optimal formula for use in the solid of the railway bottom will be determined. Final optimal recipe achieving basic required parameters for use in active zone without the requirement for frost resistance and ecology is composed of 30 % of F4-CS, 4 % of portland cement CEM II-B/LL, 3 % of lime hydrate, 70 % of recycled concrete and 10 % of fluid ash from biomass combustion.
Silicate Conductive Composites with Graphite Fillers
Baránek, Šimon ; Drochytka, Rostislav
Electroconductive composites are modern materials that are commonly used in many industries such as construction industry and machine-building industry. For example, these materials can be useful as sensors for monitoring changes in constructions, shielding stray currents from electrification networks, shielding electromagnetic radiation in operating rooms, cathodic protection against moisture or overvoltage protection of buildings. The topic of this post is the research of electrically conductive silicate composites with graphite-based fillers. In this research, composites with different ratios and types of graphite were tested and electroconductive properties such as impedance were monitored, as well as physical-mechanical properties such as strength. It was found that by adding 10 wt. graphite into the mixture reduces the impedance of the composites by 50 % and the compressive strength is reduced by approximately 40 %.
Possibilities of Using Waste Materials in Trenchless Renovation Piping Systems
Majerová, Jana ; Drochytka, Rostislav ; Hermann, Radek ; Figala, Petr
Properties of the resin system are key properties in the CIPP trenchless pipeline repair system. Fillers affect the properties of the resin system and the cost of renovation. One of the ecologically and economically attractive options is the use of secondary raw materials. The article describes the properties of some suitable secondary raw materials and their influence on the properties of the resin system in comparison with traditional fillers The article compares three types of secondary waste materials and the reference filler. The SiO2 content, the particle size of the filler and the mechanical parameters of the proposed recipes are most important.

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