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Possibilities of the utilization of the waste sand from the water glass production in building industry
Bílek, Vlastimil ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
Nowadays, the waste sands from the water glass production have no utilization and due to high alkali content are considered as a dangerous waste. So the aim of this thesis is to find and study some possibilities of their utilization in the building industry. First of all, some necessary analysis of these sands were performed and then some advantages and disadvantages of their application for production of materials based on portland cement and alkali activated materials were studied. Characteristics of fresh and hardened pastes, mortars and concretes containing these waste sands were determined. The most tested properties were their workability and their compressive and flexural strength. Close attention for the risks of alkali-silica reaction and for options of its suppressing by the mineral admixtures was paid.
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Modern Inorganic Building Materials Free of Portland Cement
Sadílek, Jakub ; Opravil, Tomáš (referee) ; Zmrzlý, Martin (advisor)
This bachelor’s thesis is focused on properties of modern construction inorganic ma-terials – geopolymeric concretes. In introductional part of work it is described basic theoretical background, as properties of binders, principles of setting and hardening. For preparation of geopolymer matrix was used secondary or waste materials of energetic and metallurgical industry – fly ashes and slags. In laboratory were prepared four com-positions of geopolymeric concretes combined from geopolymeric matrix with constant compostition and variable composition of aggregates. As aggregates these materials were used: three fractions of quartz sand, steel furnace slag and in one composition also crystals of mineral wollastonit. It was discovered that the use of steel furnace slag as aggregate in geopolymeric concrete has positive influence mainly to compressive strength, but the addition of wollastonite mineral do not evocate expectable increase of mechanical properties of samples.
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Hybride binders based on the high-calcium ash
Hubáček, Václav ; Cába, Vladislav (referee) ; Koplík, Jan (advisor)
The goal of this bachelor´s thesis was to develop a hybrid binder based on high calcium fly ash with the focus on addition of Portland cement, observation of hydration process, measurement of mechanichal properties, identification of hydration products and comparation with Portland cement. Hybrid binder was developer by adding different amounts of Portland cement to the selected mixture of high calcium fly ash activated by sodium hydroxide. Setting times and flexural strength and compressive strength were measured for these hybrid binders. Afterwards one type of hybrid binder was selected for more analyses (XFR, XRD, SEM/EDS and isothermic calorimetry). These analyses were also used for a sample of Portland cement and alkali activated high calcium fly ash and afterwards these three samples were compared between each other. The collected data show that the compositions of the activated fly ash and hybrid binder are very similar and the addition of Portland cement to the mixture has only a minor impact. Main hydration product for both of them was ettringite. Addition of Portland cement to the activated high calcium fly ash has positive impact on mechanical properties, it shortens the start of setting time of a mixture and it also increases early and later compressive strenghts.
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Study of volume changes of binders silicate
Nováček, Jaroslav ; Rovnaníková, Pavla (referee) ; Steuer,, Radek (referee) ; Pavlík,, Zbyšek (referee) ; Šťastník, Stanislav (advisor)
In theory, this work is devoted to the principles and methods of measurement of volume changes of mortars and concretes. Emphasis is placed on cement self-levelling screeds with initial shrinkage compensation. In the practical part of the work is devoted to the development of prototype measuring system designed for non-contact detection of volume changes hydrating silicate. Using the new measurement method is also practically examined the influence of boundary conditions on hydration volume changes of selected silicate binders, cement mortar and cement levelling compound based on four different connective concepts. In the calculation, this work focuses on the numerical modelling of volume changes of the examined compounds.
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Development of materials for 3D printing of elements meeting the requirements of transport structures
Romanová, Dorota ; Melichar, Jindřich (referee) ; Žižková, Nikol (advisor)
This bachelor thesis deals with the use of supplementary cementitious materials as a partial replacement of Portland cement in cement composites, focusing on the requirements of transport constructions. The theoretical part consists of a description of the input raw materials as well as cement substitutes, the studied properties of the 3D printed mixtures and a description of the characteristics of the technology. The practical part is focused on the experimental testing of the selected properties with monitoring of the influence of polymer and bio-polymer additive dosage in the proposed formulations and subsequent analysis of the most convenient one for 3D printing.
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Use of calcined clays for polymer modified mortars
Macíková, Barbora ; Sokola, Lubomír (referee) ; Žižková, Nikol (advisor)
This bachelor thesis deals with the use of metakaolin as a partial cement replacement for polymer modified mortars. The theoretical part describes negative impact of cement production on the environment. Attention is being paid to the use of supplementary cementitious materials in an effort to reduce the carbon footprint, with the metakaolin being considered as the main alternative. Its composition, availability, use, properties and suitability for use in polymer modified mortars are investigated. The practical part is focused on the verification of the relevant properties of mortars with metakaolin as a binder component and its suitability for future use as a supplementary cementitious material.
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Influence of hydration accelerators on zinc - doped cement mortars
Beneš, Pavel ; Šilerová, Iva (referee) ; Šiler, Pavel (advisor)
This work deals with monitoring the hydration of cement mortars and cement pastes made from CEM I 42.5 R cement doped with zinc oxide in an amount of 1 % wt. To eliminate the delay in the onset of hydration due to the presence of zinc oxide, the following accelerators were added to the cement mixtures in different proportions: calcium oxide, formic acids and calcium formate. Hydration was monitored using isoperibolic calorimetry. Furthermore, the mechanical properties of mixtures were investigated, namely the tensile strength after bending and the compressive strength after 7 days and after 28 days. The cement mortars were further subjected to additional analyses, such as porosimetry, DTA/TG and SEM.
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Influence of calcium sulphate type on hydration of Portland cement
Šimčíková, Ivana ; Šiler, Pavel (referee) ; Šoukal, František (advisor)
My bachelor thesis deals with the study of the influence of calcium sulphate types on the hydration of Portland cement. Hydration is performed at 15 °C, 25 °C and 40 °C. In the theoretical part we find a description of the hydration of Portland cement and the influence of the type and amount of gypsum on the hydration period. The experimental part contains the preparation of samples for measurement and the principle of calorimetry including a description of the calorimetric curve. The data obtained from the calorimetric curve was processed into ternary diagrams for illustration. The diagrams show that the more calcium sulphate is soluble, the shorter the induction period, the times of reaching the minimum heat flow and heat flow at the maximum silicate peak will have. Further, the diagrams showed that as the amount of water in sulphate increases, so does the amount of hydration heat released.
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