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The development of the solidification material from hybrid cement based on slag
Valach, Jakub ; Janča, Martin (referee) ; Koplík, Jan (advisor)
The bachelor thesis is focused on the research and development of hybrid cements based on slag. The base is granulated blast furnace slag, which serves as a substitute for cement, cement is used as an admixture. Various additions of cement and activator are monitored. The mixture is activated by Caustifying limestone. Firstly, the strengths of the mortars are mixed and measured without the addition of cement in order to find a suitable ratio of activator and slag. Subsequently, I focused on mixing and measuring the strength of mortars with the addition of Portland cement and I looked for suitable samples, which I analyzed by XRD, EDS, SEM. I also determined their stiffening time, lavish and volume stability.
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The influence of barium oxide on the formation and properties of portland clinker
Zezulová, Anežka ; Šoukal, František (referee) ; Opravil, Tomáš (advisor)
Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes, or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present master’s thesis examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulfate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point integration), as well as the effects on the variations of temperature of the phase formation (TG-DTA) and the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS, and the solubility of barium phases by ICP-OES. The hydration of clinker minerals containing barium was studied by isothermal calorimetry.
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Influence of ettringite formation on mechanical properties of zinc doped cements.
Kunovský, Ondřej ; Matějka, Lukáš (referee) ; Šiler, Pavel (advisor)
This bachelor thesis deals with the study of the effect of hydration accelerators in cement pastes doped with zinc ions. Their influence on hydration reactions, mechanical properties and the amount of ettringite formed was studied. CEM I 42.5 R cement was used and zinc was added in the form of ZnO in an amount of 1 wt. % of Zn relative to cement content. Strengths were measured over a time horizon of 98 days. In addition, analyzes by SEM, XRD and DTA methods were performed on selected samples to determine the amount of ettringite. It has been found that compressive strengths can also decrease during hydration. At this decrease, SEM, XRD and DTA showed a reduction in the amount of ettringite in the sample.
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Hybrid systems based on alkali activated materials and Portland cement
Bradová, Lada ; Koplík, Jan (referee) ; Kalina, Lukáš (advisor)
The most promising route to improve the sustainability of cement is to produce the blended Portland cements with supplementary cementitious materials. Blast furnace slag (BFS) is one of the significant pozzolan source used worldwide in blended cements contributing to lowering of the environmental impact of cement industry. On the other hand, the replacement of the Portland clinker is connected with the undesirable effects such as reduction of early strength development. In order to overcome this disadvantage, the study deals with the development of hybrid cements in which the utilization of solid waste alkaline activator quickly awakens the pozzolanic properties of BFS. The new types of blended alkali activated cements were designed to meet the European standard EN 197 1 and classified to the Blastfurnace CEM III/C cements in accordance with the mechanical, physical, chemical and durability requirements. The effect of alkali activation caused an increase in early (2 days) compressive strength development in comparison with reference sample. The setting time was delayed two times which is also interesting from the point of view of concrete production. Moreover, this non traditional hybrid alkali activated Portland cement provides considerable ecologically and economically potential.
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The study of zinc influence on Portland cement hydration.
Ptáček, Martin ; Janča, Martin (referee) ; Šiler, Pavel (advisor)
The topic of this work is the monitoring of the effect of zinc on the hydration process in Portland mixed cement (specifically with the addition of finely ground granulated blast-furnace slag, high temperature fly ash and fluidized bed combustion filter ash). How much zinc and at what time it remains in the pore solution during hydration. Activation energy of a mixture of cement with zinc in the form of soluble salts (Zn(NO3)2.6H2O and ZnCl2) and insoluble oxide (ZnO) by isothermal calorimetry was also investigated. The XRF method has shown composition during hydration. The zinc retardation effect was investigated by isothermal calorimetry and activation energy was calculated using this method. The XRF and ICP-OES methods were used to measure the zinc content of the pore solution. And the amount of portlandite was monitored by the DTA and XRF method.
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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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