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Development of phase composition in silicate systems by available methods and their optimalization
Opravilová, Lenka ; Palou, Martin (referee) ; Škvára, František (referee) ; Havlica, Jaromír (advisor)
One of the most prominent measurable parameters of the development of phases and phase transformations in inorganic systems are undoubtedly the volume changes of silicate matrix. The study of volume changes is crucial in the terms of usable durability of final product. They represent shrinkage or expansion of the material and may lead to significant decrease of technological and ecological parameters and often to complete destruction of these materials. Most often the volume changes can be observed when cement is used as a binder and in concretes, mortars, artificial aggregates and other similar materials. There are many methods to detect, define and determine the volume changes qualitatively or quantitatively. The development of phases was investigated as a part of the dissertation thesis and hence the volume changes were observed under the conditions closest to the real state in the construction industry. The raw materials and admixtures were selected which model the content of hazardous components present in conventional materials (both natural and secondary), used in construction and the relationship with volume changes was searched and demonstrated. The contacts for measuring the volume changes were attached to test surfaces of specimens and the physical - mechanical tests (volume changes, phase changes, strength, etc.), chemical analysis and ecotoxicity tests depending on the length of hydration were performed.
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The effect of aggregate type on the properties of lime mortar
Žižlavský, Tomáš ; Rovnaníková, Pavla (referee) ; Vyšvařil, Martin (advisor)
The thesis is focused on the comparison of the role of different types of aggregates and the binder-aggregate ratio on the properties of lime mortars. The theoretical part of the thesis deals with the effect of properties of aggregate, a binder-aggregate ratio and a use of calcareous aggregate, especially limestone, on the properties of mortars. It also deals with the utilization of limestone as aggregate in a history of masonry. In the practical part of the thesis there is a comparison of physically-mechanical and microstructural properties of mortars prepared with different type of aggregate (siliceous sand and limestone aggregate), with varying binder-aggregate ratio and also with a partial substitution of the aggregate by limestone fines. It was found that the usage of limestone instead of quartz sand produces the mortar of comparable properties. The partial substitution of the aggregate with limestone fines caused noticeable growth of strength, especially in mortars with higher binder-aggregate ratio.
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Change in the durability of concrete made of recycled concrete by alternative addition of ceramic admixtures
Stavař, Tomáš ; Hoffmann, Oldřich (referee) ; Stehlík, Michal (advisor)
The master thesis dealing with problematic about durability of concrete, with use of recycled concrete and addition of silica additions. Predominant for resistance of concrete constructions is surface layer, through which aggressive gasses and liquids penetrate from surrounding environment. The most important indicator of concrete durability is ability of surface layer transmissions of aggressive substants. In experimental part will be defined the actual state of surface layer by normal testing methods. The transmissions of surface layer will be tested on concrete cubes. Tests for transmissions of air (method TORRENT), of water (method ISAT), of acid gases (dept of carbonation by quick test in 98% CO2) will be carried out and also strength tests. Assessment of positive or negative influence of additions and amount of cement on durability and mechanical properties of concrete will be discussed in conclusion.
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The effect of aggregate type on the properties of lime mortar
Žižlavský, Tomáš ; Rovnaníková, Pavla (referee) ; Vyšvařil, Martin (advisor)
The thesis is focused on the comparison of the role of different types of aggregates and the binder-aggregate ratio on the properties of lime mortars. The theoretical part of the thesis deals with the effect of properties of aggregate, a binder-aggregate ratio and a use of calcareous aggregate, especially limestone, on the properties of mortars. It also deals with the utilization of limestone as aggregate in a history of masonry. In the practical part of the thesis there is a comparison of physically-mechanical and microstructural properties of mortars prepared with different type of aggregate (siliceous sand and limestone aggregate), with varying binder-aggregate ratio and also with a partial substitution of the aggregate by limestone fines. It was found that the usage of limestone instead of quartz sand produces the mortar of comparable properties. The partial substitution of the aggregate with limestone fines caused noticeable growth of strength, especially in mortars with higher binder-aggregate ratio.
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|
|
Development of phase composition in silicate systems by available methods and their optimalization
Opravilová, Lenka ; Palou, Martin (referee) ; Škvára, František (referee) ; Havlica, Jaromír (advisor)
One of the most prominent measurable parameters of the development of phases and phase transformations in inorganic systems are undoubtedly the volume changes of silicate matrix. The study of volume changes is crucial in the terms of usable durability of final product. They represent shrinkage or expansion of the material and may lead to significant decrease of technological and ecological parameters and often to complete destruction of these materials. Most often the volume changes can be observed when cement is used as a binder and in concretes, mortars, artificial aggregates and other similar materials. There are many methods to detect, define and determine the volume changes qualitatively or quantitatively. The development of phases was investigated as a part of the dissertation thesis and hence the volume changes were observed under the conditions closest to the real state in the construction industry. The raw materials and admixtures were selected which model the content of hazardous components present in conventional materials (both natural and secondary), used in construction and the relationship with volume changes was searched and demonstrated. The contacts for measuring the volume changes were attached to test surfaces of specimens and the physical - mechanical tests (volume changes, phase changes, strength, etc.), chemical analysis and ecotoxicity tests depending on the length of hydration were performed.
|
|
|
Change in the durability of concrete made of recycled concrete by alternative addition of ceramic admixtures
Stavař, Tomáš ; Hoffmann, Oldřich (referee) ; Stehlík, Michal (advisor)
The master thesis dealing with problematic about durability of concrete, with use of recycled concrete and addition of silica additions. Predominant for resistance of concrete constructions is surface layer, through which aggressive gasses and liquids penetrate from surrounding environment. The most important indicator of concrete durability is ability of surface layer transmissions of aggressive substants. In experimental part will be defined the actual state of surface layer by normal testing methods. The transmissions of surface layer will be tested on concrete cubes. Tests for transmissions of air (method TORRENT), of water (method ISAT), of acid gases (dept of carbonation by quick test in 98% CO2) will be carried out and also strength tests. Assessment of positive or negative influence of additions and amount of cement on durability and mechanical properties of concrete will be discussed in conclusion.
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