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Qualitative and quantitative analysis of clay soils
Šašek, Petr ; Viani, Alberto ; Ševčík, Radek ; Fabeš, Roman ; Řehoř, M.
Clay minerals are a group of aluminum silicates with a layered structure, which is formed by tetrahedrally and octahedrally arranged molecules with cations of potassium, magnesium, sodium and others. By combining layers of octahedra and tetrahedra several types of layered structures may be produced, which can form various types of clay minerals in nature. Clay minerals are divided into three main groups: kaolinite, smectite and illite. The aim of the study was to qualitatively and quantitatively analyse the clay minerals in soil samples; the main objective was to determine the phase transition on the boundary of smectite and illite phases. For this purpose XRD analysis with Rietveld refinement was employed.
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Properties of commercially available, ready-to-use mortars for restoration of historic renders and masonry
Janotová, Dana ; Niedoba, Krzysztof ; Gláser, Petr ; Šašek, Petr ; Fabeš, Roman
There is a wide range of premixed, dry mortars, on the market, designed with the reconstruction of historic renders and masonry in mind. The use of such materials has some advantages, including good workability and standard quality, however, due to unknown composition, being a secret of a manufacturer, it is frequently impossible to predict their influence on the substrate and on the ageing. If the ready-to-use mortar is to be applied during the renovation of the historic masonry, it is necessary to know: how close the mortars’ properties match the properties of the original material; will the repair be durable enough and will it degrade faster than the original material. Technical information, provided by the manufacturer, does not contain such data. The only parameters given, are the strength, porosity of hardened mortar and water vapour diffusion coefficient, however, it is not specified in which conditions these values were measured.
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