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Pevnost lepených spojů obkladových panelů břízová překližka sklo
Matějovská, Lucie
The diploma thesis deals with gluing selected types of wooden materials (birch and beech plywood) with glass and two types of adhesives (Sikasil SG-20 and Soudal PU Construct). The strength of bondes splices was measured by tensile and bending test in an Instron 3365 tensile test machine. The theoretical part focused introduction of basicofbonding technology. The practical part focused made of bonding splicesand evaluation of results from tensile and bending test.
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Klikov Formation in a newly localized landslide area near České Budějovice
Pilařová, Eliška ; Jerman, Jan (advisor) ; Mužík, Vlastimil (referee)
Diploma thesis is focused on obtaining new knowledge about the Klikov Formation of the České Budějovice Tertiary Basin during the extraordinary opportunity of construction a section of the D3 highway at the southern edge of České Budějovice near the villages of Roudné and Včelná. The location is also interesting because of newly detected landslide. The route of the highway is designed in large side-hill cut. The cut reached a total height of up to 20 m and was mainly carried out in the soft rock of the Klikov Formation, while vertical rock slopes up to several meters high remained without any stabilization during excavation. This made it possible to examine the soft rock of Klikov Formation in various aspects, e.g. stability, structural properties, properties of the rock material itself, etc. The text is divided into two parts. The first part describes construction works during the excavation of side cut, and the second to laboratory tests. The diploma thesis presents the connection between field observation and laboratory results.
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Experimental investigation of shear strength of soils from the Dobkovičky landslide area and development of correlations between soil strength and their physical properties
Roháč, Jakub ; Mašín, David (advisor) ; Blahůt, Jan (referee) ; Hrubešová, Eva (referee)
Critical and residual states are key soil conditions relevant to slope stability. Evaluating the available shear strength in relation to these conditions is crucial for reliable stability analyses. The best way to determine the strength parameters is through properly selected laboratory tests of soil mechanics. However, in specific cases, these parameters can be estimated based on other material properties of soils. The work clarifies the applicability of various correlation equations from the literature and proposes new relationships, created from laboratory- determined results of strength and index parameters of soils from the Bohemian Central Mountains. It shows how different equations or different material properties of soils can predict the required value of strength. The work also describes how the residual strength of soils and its estimation can be affected. This is mainly caused by the clay fraction proportion and by the shear rate used in its laboratory determination. The results are applied to a specific geotechnical problem - to estimate the critical state and the residual friction angle of soils from the selected study area of the D8 motorway, which is well known thanks to the stability problems. Last but not least, various errors and misunderstandings are discussed, which are often...
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Gluing of FDM 3d printed parts from PLA
Šlimar, Filip ; Slaný, Martin (referee) ; Zemčík, Oskar (advisor)
The thesis deals with the theory of 3D printing, materials for printing and bonding. It focuses on FDM printing and PLA material. It also compares gluing with other methods and deals with the distribution of adhesives, the gluing procedure and tests of glued joints. The work, based on literature studies, proposes an experiment to evaluate selected adhesives. The practical part contains a description, results and evaluation of the experiment. The evaluation of adhesives is based on tensile and shear strength.
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Bio-based wood adhesive derived from brewers spent grain
Muselíková, Vladislava
Brewers spent grain (BSG) is an abundant waste material from the brewing process, representing approximately 85% of total by-products generated, is rich in cellulose and non-cellulosic polysaccharides and has a strong potential to be recycled. One of the main components of the BSG is protein, which has a potential to be extracted, modified and used as an adhesive for the woodworking adhesive. This work deals with the protein extraction through alkali treatment and its subsequent modification, crosslinking with glyoxal. The crosslinked adhesive was tested through ABES method to find, that ideal content of glyoxal is 20%. Subsequent adjusted standard tests for the lap shear strength and bend strength (MOE and MOR values) were used to compare its values to commercially available PVAc adhesive. The lap shear strength results were 2,7 times lower to PVAc, the bend strength values were, on the other hand, 1,5 times higher. The PVAc was partially replaced (50 and 25%) by the protein adhesive showing that the extracted adhesive could serve as a partial replacement to lower the ecological impact of the PVAc adhesive.
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Přírodní lepidla na bázi krve - pevnost lepeného spoje u rostlého dřeva
Pluháček, Viktor
This bachelor thesis is an experiment with a focus on the use of adhesives from natural and renewable sources. Adhesives used are Henkel's PVAc glue, Ponal Super 3 and the blend of bovine blood, slaked lime, bile and milk. Two types of test specimens were made from spruce and beech boards. One type tested for shear strength and the other for tensile strength perpendicular to the adhesive joint. Part of the samples were subsequently conditioned and the other tested by soaking in water to determine the durability class according to EN 204: 2001. After being removed from the water, soaked samples were conditioned. Followed by their testing.
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Využití alternativních výztužných materiálů ve vrstvených lepených materiálech
Svatoň, Kryštof
Thesis deals with possibilities of reinforcement of plywood boards with natural materials in order to improve mechanical and physical properties. 5-layer spruce boards were reinforced under top layer with basalt fabric and jute. There was used environmental friendly glue for plywood fabrication. Results indicate increase in mechanical properties of boards with basalt fabric reinforcement. Mechanical properties of boards reinforced by jute were decreased.
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Pevnostní vlastnosti lepidlových filmů v závislosti na klimatických podmínkách lepených spojů
Knápková, Adéla
The diploma thesis deals with influence of climatic conditions on the strength properties of adhesive bonded joints of outdoor wood furniture by using dispersion-based PVAc adhesive for assembly joints. Samples of acacia, beech and larch wood were glued with waterborne polyvinyl acetate adhesive. The glued joints were exposed to various humidity and temperature conditions in order to monitor the influence of climatic conditions on the shear tensile strength of adhesive film of individual wood species.
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Study of properties of polymer-modified cementitious adhesive material during shear stresses
Powetz, Dominik ; Nováček,, Jaroslav (referee) ; Žižková, Nikol (advisor)
This bachelor thesis deals with the study of the properties of the polymer modified cementitious tile adhesives during shear stress. In the theoretical part of this thesis is described the influence of absorption of the tile and the content of polymer powder on tensile adhesion and shear strength. After that, the review of known methods for determining the shear strength of adhesives and mortars was done. In the last step of the theoretical part, this bachelor thesis is focused on the most common building defects and failures that occur during the tiling and their subsequent use in the construction of wall cladding elements and ceramic floor tiles. The practical part of the bachelor thesis is focused on the design and testing of an alternative method for the determination of shear strength of bonding, with the effort to achieve the simplest and the most economical option for testing (easy sample preparation, low demands on instrumentation) with the possibility of replacing the known method DIN 18156-3 for testing shear strength of cementitious tile adhesives.
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New directions for waterproofing of underground transport
Čech, Tomáš ; Čížek, Luboš (referee) ; Šťastník, Stanislav (advisor)
This diploma thesis focuses on the implementation of waterproofing of underground constructions using an LLDPE membrane hinged on anchors. In the future, this method will replace the commonly used waterproofing system in Scandinavia with extruded polyethylene foam. This method of tunnel construction and waterproofing is compared with the NRTM method, often used in Central Europe. The thesis describes the installation of a waterproofing system, especially materials, accessories, welding devices and auxiliary installation equipment. The main focus of the thesis is to verify the reliability of the individual types of welds and to assess the waterproofing system in terms of implementation and environmental demands.
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