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Influence of calcined clays on the properties of cement pastes
Florian, Vojtěch ; Šilerová, Iva (referee) ; Šiler, Pavel (advisor)
V této práci byl studován vliv kalcinovaných jílů na vlastnosti portlandského cementu. Jíly a jílové materiály jsou studovány již mnoho let, přičemž nejvíce studovaný jíl je kaolín a kalcinovaný kaolín. Avšak kvůli změnám ekonomické situace původně levné materiály, např kaolín, zdražily. Vzhledem k důležitosti ekonomické stránky byly v této práci používany primárně jílové materály, které by bylo možné považovat za odpadní. Studovali jsme směs přírodních a syntetických jílů získaných z okolí Brna v České Republice, což je region bohatý na ložiska jílů. Tyto jíly byly analyzovány, kalcinovány, pomlety a byla u nich změřena pucolánová aktivita. Nově schválená norma ČSN EN 197-5 povoluje až 65% náhradu cementu jinými materiály, např jíly, což je téměř dvojnásobek v porovnání s původní maximální náhradou 35 %. Z toho důvodu byly v této práci připraveny cementovo-jílové směsi s až 70% obsahem jílu. Bylo zjištěno, že cementovo-jílové směsi s 60% obsahem jílu vykazovaly mechanické vlastnosti přinejhorším srovnatelné s referenčním vzorkem portlandského cementu, v některých případech měly tyto směsi dokonce lepší mechanické vlastnosti. Směsi s obsahem jílu kolem 30-40 % měly všeobecně lepší mechanické vlastnosti než referenční vzorek. Ze studovaných materiálů měly směsi připravené z jílu z opuštěné cihelny nejlepší ohybovou pevnost. Při stáří 28 dní měly směsi až o 60% vyšší ohybovou pevnost než referenční vzorek. Nejvyšší tlakovou pevnost vykazovaly cementovo-jílové směsi připravené z glaukonitického jílu. S rostoucím obsahem jílu tlaková pevnost klesala. V 90 dnech při 10% obsahu jílu měla směs o 60 % vyšší pevnost než referenční vzorek. Při 60% obsahu jílu byla pevnost ve srovnání s referenčním vzorkem o 26,5 % vyšší. Použití těchto cementovo-jílových směsí se zdá být slibné díky dobrým mechanickým vlastnostem a z ekonomického a ekologického hlediska. Tyto cementovo-jílové směsi by mohly snížit emise oxidu uhličitého a zároveň být levnější než portlandský cement.
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Fireclay Grog with a High Alumina Content
Mezulianík, Tomáš ; Tvrdík,, Lukáš (referee) ; Nevřivová, Lenka (advisor)
Special refractory grog with increased alumina content are not currently produced in the Czech Republic. The price of these grogs produced abroad is high, so there is an effort to produce grogs using domestic waste fractions of claystones, which have been stored for decades. The theoretical part of the thesis describes the current results and experience with the processing of fine waste parts of claystone W super and BVP. Suitable raw materials for the preparation of grog with an increased content of alumina are characterized. In the experimental part of the thesis is verified the possibility of production of grogs with increased content of Al2O3 according to the proposed prescriptions.
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The Use od Rammed Earth for Residential Buildings
Zadražil, Lukáš ; Remeš, Josef (referee) ; Žižková, Nikol (advisor)
The Bachelor thesis focuses on use of earth as a building material for residential buildings, in particular the rammed earth technology. The first part of the thesis deals with history of the earth structures in the world and in our country, using the Czech and foreign literature. Subsequently, the thesis defines earth as a building material. After that, the paper describes in detail the rammed earth technologies with examples of use in modern buildings around the world. Within the practical part, samples of earth from Dolní Těrlicko, approx. 30 km southeast of Ostrava, have been collected. Family house should be built on this land next year, with usage of rammed earth technology. In final part we propose and test methods of producing trial bodies from earth compound for pressure test.
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Color Changing of the Ceramic brick.
Kocmánek, Tomáš ; Zach, Jiří (referee) ; Nevřivová, Lenka (advisor)
The bachelor’s thesis is focused on color correction of brick body. There are examples of pigments commonly used in various industrial fields, as well as studies on the use of waste products as additives in brickmaking industry, altering, among other things, the color of the brick body. In the experimental part of the thesis the effect of three selected ferric pigments and two selected correction clays on the color and selected physico-mechanical properties of the brick body was investigated.
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Continual helicoidal mixer
Radoš, Pavel ; Malach, František (referee) ; Malášek, Jiří (advisor)
This work contains a proposal for constructions and workings of a worm mixer of clay, lime, cementand fly ash with water for delivery quantity 18 tons per an hour. The introduction describes problems of mixing and mixers in the preparation of building materials. I have mentioned calculation of the main proportions and drive under the relevant norms and self-fortress control of the stresssed parts of mixer. Drawing documentation is worked into the ACad program and contains the configurations of the proposed machinery and detailed subassembly of important parts of worm mixer.
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The Essence of earthen Architecture in the Czech Republic
Bažík, Lenka ; Pifko,, Henrich (referee) ; Novotný,, Martin (referee) ; Žabičková, Ivana (advisor)
For ten thousand years people have used earthen building material in their homes and in just the last hundred years advanced society has gradually turned away from it due to the development of modern technology. Earth is currently of little use as a building material, but it is gradually increasing with the importance of sustainability. Earth has its place in contemporary modern architecture and this is what this work tries to point out. The research is based on the assumption that each building material gravitates with its properties, composition and also the knowledge of the builder to create a certain space. Different building materials define different spaces, different construction uses and different details. This research defined the network of knowledge with the central themes of the essence of earthen architecture by the method of grounded theory and subsequently applied the theory in the design of a model case. The proposed small structure represents an ideal rendering of the space from a single material on the basis of acquired and known information about this material. It has massive earthen walls, which man created himself and it provides him the shelter. The shelter rises smoothly from the ground, its main source, it has soft round features, which were created by the touch of human hands, and when it expires, it naturally merges with the ground again.
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The development of grouting for additional sealing of embankment dams
Michalčíková, Magdaléna ; Klablena,, Petr (referee) ; Drochytka, Rostislav (advisor)
Seal of sand or gravel by chemical injection is known and used for a long time. Chemical grouting are however expensive and sometimes the use of cement does not lead to desire effects. So it is trying to find new materials and methodologies injection arrangement works. To achieve savings of chemical products are added to a mixture clay and cement. Clay-cement grouting mix are used not only in order that they are better quality, but also because in this way proposed mixtures have a tendency to penetrate better into incoherent sediments that need additional sealant of chemical injection. For further possible reductions of economic terms the mixture is trying to replace the classic clay. As a suitable substitute for classic clay is to a certain extent the use of secondary raw materials. Above all it is fly ash. As a part of my thesis I deal with the appropriateness use of these materials and examining their properties in the mixture. It was found that by using fly ash were improving consistency of the fresh mixture, reducing the amount of water-cement ratio and reduce shrinkage of the mixture. On the other hand, by using fly ash has been increasing decantation, permeability atc. In the next stage of my work was examined the influence of the quality of cement, lime and liquefaction in the mixture. The aim of thesis is to propose the optimal injection mixture for additional sealing earth dams.
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Utilization of liquefied soils in the form of backfilling self-compacting grouts
Chlachula, Jakub ; Krejčí, Pavel (referee) ; Drochytka, Rostislav (advisor)
The bachelor thesis focuses on the research of liquefied soils based on backfilling self compacting grouts. These grouts could be used as bedding for utility lines with lower cost and without unnecessary waste. The prerequisite is that the soil will be stabilized by a suitable stabilizing admixture, which should increase the strength of the composite. It will be necessary to liquefy this composite by using water and suitable liquefaction or plasticizers. As part of this thesis, currently known and used stabilizing admixture and plasticizers are also evaluated, same as the geological situation in the Czech Republic.
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Statistical analysis of the acceptance tests of ground anchors
Štefaňák, Jan ; Hrubešová,, Eva (referee) ; Záleský,, Jan (referee) ; Masopust, Jan (advisor)
The objective of dissertation is to find the approaches for processing the data extracted from the reports that document the performing of acceptance tests of ground anchors. The purpose of this activity is to allow further utilization of this data for designing practice. 795 test records were collected. It is essential for the correctness of analysis, that the whole anchor bond must be placed in homogeneous material. The records for anchors that don’t fulfilled this condition were removed. The set of 379 records of anchors installed in six different soil types during construction work in Czech Republic remained. All those anchors were tested according the demands of european standard ČSN EN 1537:2001, valid until 2013. The methodics based on the mathematical statistics, regression analysis and probability methods were compiled during solving the task defined above. The major result of data processing that was performed via methodics based on combination of mathematical statistics and probability simulation methods is the set of bond shear stress parameter values elaborated for variety of soil types. The regression model for determination of the force-displacement curve and the model predicting the creep behavior of loaded ground anchor were constructed, where the creep value is dependent on the tendon bond length, tendon free length and on the level of prestressing force. The description of full-scale experiment, whose results were used for verification of assumptions incorporated in relevant methodics, is included. The example of determining the probability of failure of anchored structure using the stochastic simulation technique is mentioned also, where the previously obtained results are used as input values for this calculation. Moreover, the software application serving for automatization of processes associated to conducting of the tests of ground anchors and to creating the test report is introduced.
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