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Lightweight concrete with reinforcement
Plochý, Ondřej ; Hubertová,, Michala (referee) ; Hela, Rudolf (advisor)
This bachelor thesis summarizes the current knowledge regarding to the design and properties of lightweight concrete and concrete with reinforcement. Also deals with research of lightweight aggregate concrete with Liapor and its interaction with dispersed steel fibers. The work examined recipes of volume classes D1,6 and D1,8 and strength classes SFRLC 20/22 and SFRLC 25/28. Recipes are monitored by physical-mechanical and rheological properties.
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Study of the effect of the application of cellulose fibers in cementitious composites
Dvořák, Richard ; Herka, Petr (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis is focused on composition and processing of cellulose fibers and their usage in cementitious composites. It describes key attributes of cellulose fibers, which has to be acquired for effective use in cement composites. There are stated effects of cellulose fibers on concrete properties, such as workability, physical and mechanic attributes and freeze-thaw resistance. In experimental part is designed a mixture with portion of cellulose fibers. There has been performed various tests to define the effect of cellulose fibers. There was designed experiment to determine its alkali resistance for fibers itself, and possible changes in microstructure of fibers were analyzed by optic and electron scanning microscope.
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High-performance concretes based on the secondary raw materials
Sáček, Josef ; Brandštetr, Jiří (referee) ; Šoukal, František (advisor)
This work is devoted to study of physical-mechanical properties and structure of high performance concretes (HPC) based on portland cement. The attention is focused on possibility of substitution of economic high-cost components of concrete with utilization of secondary raw materials or cheaper components. Properties of raw materials and their influence on whole quality of concrete were tracked by various methods. Mechanical properties of prepared HPC samples were tested especially (compression and flexural strength) with further microscopic study of structure. Isoperibolic calorimetry and X-ray powder diffraction method were also used for concrete characterisation. These methods allowed to determine the influence of raw materials on prepared HPC and to carry out a certain optimization among price and quality of this material.
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Latexes modified cementitious materials
Vinter, Václav ; Krátký, Josef (referee) ; Šoukal, František (advisor)
In this thesis, the development of mechanical properties and structure of latex modified cementious materials during hydration was studied. Latex modified materials are composites of inorganic cement (portland cement) and organic polymer latex. Preparation, processing and fabrication of the polymer cement material based on portland cement was optimized with aim to reach the most compact structure of the product with the finest mechanical characters. The experimental part was pointed to observe influence of the type and amount of polymer latex with focus on mechanical characters and hydration kinetics with given filling as well as without it. In presented work, the possibility of compaction of the material by high-shear mixing within twin-roll mixer (the prototype for production of MDF composite) was verified. The second part of the labor was aimed to analysis of prepared polymer-cementitious material. For determination of influence of batching of added polymer latex on hydration of cement paste the thermal analysis (DTA/TGA) and infrared spectroscopy of composite was done. At last the microscopic observation by optical microscope was carried.
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The effect of particles size on the properties of mortars.
Sehnal, Tomáš ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
The consumption of concrete as a building material is still increasing over the world. Concrete production is closely associated with CO2 and other greenhouse gases emissions. The reduction of these emissions can be achieved by a higher utilization of secondary raw materials in cement mixtures. This bachelor work is focused on the using of secondary raw material, finely ground granulated blast furnace slag and fly ash from fluidized bed combustion and high temperature combustion. The properties of milling pure cement and cement mortars with addition of secondary raw material will be measured. Compressive strength, flexural strength, and calorimetric measurement will be performed for these prepared mortars.
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Possibilities of utilization of solid residues from fluidized bed combustion for preparation of composite Portland cements
Beranová, Denisa ; Šiler, Pavel (referee) ; Opravil, Tomáš (advisor)
The bachelor thesis deals with possibilities of utilization of solid residues from fluidized bed combustion of coal, bed and filter ash, to be used in the production of composite Portland cements. 6 ash types were investigated, of which 3 were bed ash (finely ground) and 3 were filter ash colected from Ledvice, Tisová and Poříčí K8 power plants. The chemical composition of the ash collected was determined and the progress of a hydration reaction monitored, and then samples mixed with Portland clinker were prepared. Their respective compressive strength and flexural strength were then analysed and observations made on the hydration and composition of products of the hydration reaction. Finally the results of selected mixtures were verified with prepared standardized mortars.
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The effect of fly ash on the properties of cement mortars.
Bayer, Petr ; Brandštetr, Jiří (referee) ; Šiler, Pavel (advisor)
The consumption of the cement for construction industries is increased every year. That is associated with greenhouse gas emissions, especially carbon dioxide CO2. Reduction of greenshouse gas emissions can be achieved by maximisation of the use of cementitious and pozzolanic by-products. As by-product could be used blast furnace slag and fly ash. My bachelor’s thesis is focused on the possibility of the partical replacement of the cement by fly ash. High temperature and fluidized fly ashes will be tested. The goal is to examine the behavior of the cement mortars in compensation of 10, 20, 40 and 60 % by weight of cement by fly ash. The compressive and flexural strength and isoperibolic calorimetry measurement were performed.
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Lime mortars with the addition of ground limestone
Žižlavský, Tomáš ; Rovnaníková, Pavla (referee) ; Vyšvařil, Martin (advisor)
The thesis is focused on an effect of addition of ground limestone on properties of lime based mortars. Theoretical part of the thesis deals with diferenciation of plasters and their utilization, history of using limestone as an aggregate, its exploitation in the present and its impact on properties of lime based plasters, specially on strenghts. In the next part there's elaborated the carbonation reaction including the influence of external agents. Practical part of the thesis is focused on proving assumtions from theoretical part, particulary on the influence of ground limestone on the strenght properties of lime based plasters.
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Comparison of selected parameters of tensile strength of concrete
Rozsypalová, Iva ; Žítt, Petr (referee) ; Daněk, Petr (advisor)
The thesis deals with a comparison of the selected strength tension properties of the hardened concrete and finding relationships between them. This is essentially a simple tensile strength, tensile flexural strength and tensile splitting strength. The text describe the testing procedures to determine the tensile strength of concrete. Furthermore, there are presented the results of testing on different types of concrete (plain concrete, lightweight concrete, steel-fiber concrete, polymer-fibre concrete and high strength concrete). The conclusion deals with the derivation of dependancy between concrete strengths and comparing the values obtained from the available relations with the results of the tests.
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Cement composite materials with polypropylene fibers
Preisner, Martin ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with summarizing the possible effects of the addition of polypropylene fibers, especially low temperature plasma treated on the properties of cement composites and concrete. They are given basic information and distribution of polypropylene fibers. It describes the finish polypropylene fiber low-temperature plasma. The experimental part focuses on the effect of dispersion of polypropylene fibers treated plasma in the cement matrix.
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