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Study of carbonatation in alkali activated systems
Suchý, Rostislav ; Koplík, Jan (referee) ; Kalina, Lukáš (advisor)
The carbonation of the building materials based on the ordinary Portland cement is relatively well-known and extensively studied phenomenon. Conversely mechanism, reaction products and factors affecting the carbonation of the alkali activated materials are still not sufficiently clarified. In this work, the progression of the carbonation of the alkali activated materials under different conditions was investigated. The reaction products and the microstructural changes were determined by XRD respectively SEM-EDX analysis. The corrosive conditions due to the decreasing of the pH of the binders by the carbonation were observed by XPS analysis of the steel fibers. The carbonation of the alkali activated samples was compared with the reference samples based on the Portland composite cement. Besides these analyzes, the mechanical properties of the binders were monitored.
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Investigation and Modelling of Concrete Carbonation
Rovnaníková, Markéta ; Keršner, Zbyněk (referee) ; Bajza, Adolf (referee) ; Havlica, Jaromír (advisor)
The corrosion of steel reinforcement is probably the most frequent type of degradation of reinforced concrete structures. Reinforcing bars are protected from corrosion by a thin iron oxide layer which is formed on their surface due to a high alkalinity of the surrounding concrete. Corrosion may start when this layer is destroyed (i) either by chloride ion penetration (when the concentration of dissolved chloride at the depth of the reinforcing steel exceeds a critical value) or (ii) by a reduction in the pH value of pore solution to values below 9.5. Such a reduction in alkalinity is the result of carbonation of the Ca(OH)2 in the concrete mass, i.e. of its reaction with the atmospheric CO2. The main aim of this work is an experimental investigation and modelling of carbonation process. The effect of relative humidity, curing period and replacement of Portland cement by supplementary cementing materials (SCM - fly ash, blast furnace slag and metakaolin) on carbonation process has been studied. Calcium hydroxide content in the presence of SCM and their pozzolanic activities have been also determined. Furthermore, lots of parametric studies and comparison of carbonation models have been provided. The software tools based on the introduced models and considering the input data to be statistically independent random variables have been described and used for other parametric studies.
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Investigation of portlandite carbonation using the in-situ X-ray diffraction analysis
Růžička, Lukáš ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
Thesis deals with carbonation of portlandite using in-situ X-ray diffraction analysis. The carbonation of portlandite progress in concrete structures and it is already quite widely discussed. It is responsible for corrosion and degradation of reinforced concrete elements, and thus its influence is perceived very negatively. The main goal of this work is to determine the ideal conditions for the progress of carbonation of portlandite. In this work the progress of carbonation depending on the relative humidity and temperature was observated. The amount of carbonated portlandite was evaluated by means of thermal analyzes (TG / DTA) and X-ray analysis.
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Survey and Diagnostics of Building Construction
Haloun, Jan ; Cikrle, Petr (referee) ; Anton, Ondřej (advisor)
The topic of the first part of this bachelor thesis covers the methods of diagnostics of reinforced concrete constructions and their practical application. In the theoretical part are described the methods currently used with diagnostics of reinforced concrete constructions with focus on methods used in practical part. The practical part covers the survey of reinforced concrete constructions and its evaluation. The main objects of the practical part were the detection of the strength class of concrete and real reinforcement of certain elements.
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Diagnostics of bridge structure
Nápravník, Petr ; Žítt, Petr (referee) ; Láník, Jaromír (advisor)
This bachelor´s thesis deals with construction-technical survey of a highway bridge no. D1-243 across Ripska street at suburbs of Brno. Theoretical part contains bridge terminology, inspections, problematics of prefabricated beams I-73, construction-technical survey and description of laboratory tests. Practical part deals with making of a construction-technical survey, evaluation of construction parts and a summary of results.
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Preparation and implementation of construction and technical survey of a building
Šebela, Václav ; Heřmánková, Věra (referee) ; Anton, Ondřej (advisor)
This bachelors thesis covers preparation and implementation of a construction and technical survey of reinforced concrete structure in Rousínov. The theoretical part is describing examined properties of reinforced concrete and methods of diagnostics used in this field of study. The practical part focuses on the construction and technical survey. The main focus of the survey is the quality of concrete and the assessment of reinforcement in representative parts of the structure. The last part concludes results of the survey.
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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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