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Experimental testing of elasticity modulus for base layers of pavements
Kotas, Vojtěch ; Mondschein,, Petr (referee) ; Stehlík, Dušan (advisor)
The thesis is focused on experimental testing of resilient modulus Mr with triaxial test of chosen unbounded and bounded mixtures used in the sub-base layer of pavement. The reason of testing is to compare results with TP 170 – pavement construction guide containing commonly used values of resilient modulus Mr. Thesis should check if those values are correct and real. For classification of chosen materials there are used another tests like grain size distribution, compaction, California bearing ratio CBR for unbounded mixtures and compressive strength for cement-bounded mixtures.
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Geopolymers based on fly ashes and brick body
Řezník, Bohuslav ; Lang,, Karel (referee) ; Příhoda,, Jiří (referee) ; Žižková, Nikol (referee) ; Rovnaníková, Pavla (advisor)
In line with the current focus on utilizing side products of various production processes, this dissertation thesis analyzes the process of alkali activation of particular side products: fly ash and brick fragments. This activation produces geopolymeric materials widely used in civil engineering. The thesis aims to optimize the geopolymerization process so that the resulting geopolymer is both ecologically and economically viable. To that end, the thesis studies the course of geopolymeric reaction between the alkali activator and fly ash from: (i) the Chvaletice power plant, (ii) the Dětmarovice power plant, and (iii) biomass combustion, as well as (iv) fluid fly ash from the Hodonín power plant. All experiments of geopolymeric reaction have focused on the factors influencing the synthesis of geopolymers—that is: composition of the alkali activator, the ratio of alumino-silicate to the activator, and the impact of temperature on structure of the synthesized geopolymer. Further, the thesis analyzed the synthesized polymer’s microstructure, phase composition, resistance against corrosive conditions, and compressive strength, as well as mechanical-fracture properties of selected fly-ash geopolymers. The thesis finds that the most suitable for geopolymeric synthesis appears to be the fly ash from the Chvaletice power plant in which case the obtained geopolymers showed best properties in the studied areas. The fly ash from the Dětmarovice power plant, biomass fly ash, and fluid fly ash have failed to reach acceptable properties. Separately, the thesis studies the geopolymerization of brick body that could be suitable input for alkali activation. The geopolymers synthesized from brick fragments resulted in materials of supperior mechanical strength. A mixed use of fly ash and brick fragments failed to show a synergetic effect. Properties of the resulting geopolymers have been inferior to the properties of geopolymers produced using just fly ash or just brick body.
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Use of ultrasound testing of concrete in bridge structures
Olejková, Sabina ; Komárková, Tereza (referee) ; Cikrle, Petr (advisor)
There are analyze kinds of diagnostic methods in terms of bachelor’s thesis. It is written about principles of ultrasonic pulse method and its options of usage on the current concrete structure. There are processed results of measurement on the testing samples which will be compared with results of stress strength. There is also spoken about calibration relationships in the bachelor’s thesis. Calibration relationships are described in Czech technical norms.
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The study of the refractory concrete binding system based on phosphoric acid and aluminous cement
Pavlík, Tomáš ; Švec, Jiří (referee) ; Šiler, Pavel (advisor)
This thesis deals with refractory concrete binding system based on aluminous cement and phosphoric acid. The prepared refractory concretes were fired at 1 000 °C. Various effects on compressive strength of refractory concrete were studied. The influence of aluminous cement content and phosphoric acid content, the influence of various admixtures, the influence of plasticizers and the influence of time and method of sample storage were studied. Simultaneous thermogravimetry and differential thermal analysis of the basic unfired sample were performed. Finally, selected refractory concretes were fired at 110, 200, 400, 600, 800, 900, 1 000 and 1 100 °C. The compressive strength of these samples was measured and powder X ray diffraction analysis was performed. The compressive strength of refractory concretes under intermediate temperatures (800–1 100 °C) was most increased in samples with metakaolin and gray microsilica.
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Reactive powder composites and cement composites without macropores
Panenková, Monika ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the design principles and manifacture of ultra performance concrete (UHPC), reactive powder composites (RPC) and other fine-grained materials, such as Macro defect free (MDF) or Densified systems with small particles (DSP). Theoretical part of this work is focused on the requirements of properties and composition UHPC and RPC and methodology of their design principles. Experimental part describes design principles RPC, manufacture of test specimens, testing of certain physical and mechanical properties, such as tensile strenght, bending strenght and compressive strenght and determination chemical character X-ray and thermal analysis.
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Double-stage system of subgrade stabilization
Švarcová, Monika ; Mondschein,, Petr (referee) ; Stehlík, Dušan (advisor)
This diploma thesis is focused on the properties of unsuitable and conditionally unsuitable fine-grained soils after a one-stage or two-stage treatment by using a binder. The theoretical part occupies with problematical properties of the fine grained soils in a subgrade and a possible technology of the change of these properties. The laboratory testing of treated soils is described and a practical technology of the one stage and two-stage stabilization. In the practical part the fine grained soils are treated by one-stage or two-stage stabilization. For the one stage stabilization the cement is used, for the two-stage stabilization the properties of the soil are improved by lime and then the soil is stabilized by cement. The treated soils are laboratory tested, the initial bearing index IBI, California bearing ratio CBR, unconfined compressive strength and frost susceptibility is tested. Based on the results of the laboratory tests the benefit of the two-stage stabilization is measured.
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Influence of multiple cyclic loading on the selected parameters of lightweight concrete
Alexa, Martin ; Misák, Petr (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with the observation of the values of selected parameters (especially the static modulus of elasticity) of light-weight concrete in compression before and after multiple cyclic loading. The deformation of test specimens during multiple cyclic loading were measured with resistive strain gauges. Test specimens (cylinders with a diameter of 150 mm and height of a 300 mm) were cyclically loaded and up to 4 500 loading cycles were performed. The aim of this thesis is assessment changes in the values of static modulus of elasticity depending on the number of loading cycles.
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Testing early strength concrete by electronic tester
Holbová, Monika ; Kocáb, Dalibor (referee) ; Cikrle, Petr (advisor)
This project solves the creation of calibration relations for determining the compressive strength of early age concrete. It deals with news in the field of hardness methods. 36 samples were made for this experiment and tested by ultrasound and by impact hammer SilverSchmidt type L with Mushroom Plunger. The result is set of calibration relations for determining of compressive strength for different methods and their combinations.
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Properties of Fiber Reinforced Plastics
Jastrzembská, Alena ; Petránek, Vít (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with the theoretical part of raw materials, production and properties of composite materials with fiber reinforcement and polymer matrix. It also gives a brief overview of selected prominent Czech and foreign producers of composite materials with polymer matrix and fiber reinforcement. The practical section deals with testing the durability of selected composite profiles immersion in aggressive environments and testing of compressive strength.
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