National Repository of Grey Literature 16 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Micro-mechanical performance of concrete used as recycled raw material in cementitious composite
Hrbek, Vladimír ; Koudelková, Veronika ; Prošek, Z. ; Tesárek, P.
The reduction of industrial pollution is recently one of main goals over all fields. In civil engineering, re-cycling of structural waste provides wide opportunity contributing this effort. This paper focus on re-use of concrete waste, which after further processing can be used in new constructions as partial supplement to the mixture. To investigate the impact of re-cycled concrete addition, it is necessary to determine mechanical and structural parameters of individual phases in the “raw” material. For this purpose, grid indentation and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM, EDX) are combined to determine properties of concrete sample.
Utilization of image and signal processing techniques for assessment of built heritage condition
Koudelka_ml., Petr ; Koudelková, Veronika ; Doktor, Tomáš ; Kumpová, Ivana ; Kytýř, Daniel ; Valach, Jaroslav
Historical buildings represent invaluable heritage from the past and therefore their protection is a very important task. Assessment of their condition must not cause damage accumulation thus the least possible volume removed from the structure is essential. As many historical buildings in the Czech Republic are built using sandstone that can be considered as a typical heterogeneous system, statistical signal processing is a promising approach for determination of the representative volume element (RVE) dimensions. Such calculations can be carried out on the domain of logical arrays representing binary images of the materials microstructure. This paper deals with processing of image data obtained using SEM-BSE and high resolution flatbed scanner for determination of RVE dimensions. Advanced image processing techniques are employed and results from calculation using grayscale data are presented and compared with results calculated on the basis of color input images.
Crystallization force of sodium chloride
Koudelková, Veronika ; Wolf, Benjamin
Soluble salts are one of the most deteriorating factor causing damage of historical building materials due to generation of crystallization pressure inside pore space. Direct measurement of crystallization force is quite challenging, hence we developed at our institute a novel device able to detect the force of growing crystal. The device is based on the monitoring of force developed with upper microscopic glass on the growing crystal to maintain constant position. The crystal could generate force because of the existence of thin liquid layer of solution between both surfaces come into contact. The driving force for the subsequent growth of crystal against obstacle is supersaturation, which is mainly induced by evaporation of the salt solution. In this experiment, the crystal of sodium chloride generated force 16.8 mN and the corresponding crystallization pressure was equal to the value 0.48 MPa.
Grid indentation and statistic deconvolution: limitations and accuracy
Hrbek, V. ; Koudelková, Veronika
The evaluation of heterogeneous materials used in civil engineering on the microscopic level has become important aspect in proper understanding of the macroscopic behavior of the material. This contribution aims at advantages and problems related to the technique of grid indentation and at the evaluation of mechanical properties.
Chemical and mineralogical analyses of plaster samples from State Castle Bečov
Slížková, Zuzana ; Koudelková, Veronika ; Kozlovcev, Petr ; Šterner, Adam
Using chemical and microscopic analysis, it was determined that the analyzed sample of bedding mortar from the 13th century (Czech castle Bečov) is the air lime mortar with the quartz and silicate sand enriched by some content of slag grains. The internal plaster from the same building period of the castle was made using the lime-earthen mortar with predominantly silicate sand. The plaster contained an admixture of wood or plant particles, sawdust has been identified.\n\n
Chemical and microscopic analysis of the repair mortar, Petschek villa, V sadech 2, Prague 6
Slížková, Zuzana ; Koudelková, Veronika ; Frankeová, Dita ; Šterner, Adam
The aim of this work was to analyze the repair mortar from Petschek villa, by means of SEM-EDX analysis in order to characterize the aggregate and the binder in the mortar sample. The analyses proved the cement mortar covered with lime-cement mortar.
Chemical and microstructural characterization of the render, sampled from the Garden wall of the US Embassy in Prague 1
Slížková, Zuzana ; Frankeová, Dita ; Viani, Alberto ; Hauková, Petra ; Koudelková, Veronika ; Svoboda, Milan
The aim of the work was to analyze the mortar taken from the Garden wall (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in HCl to determine the mixing ratio.
Chemical and microstructural characterization of the render, sampled from Gloriette, the US Embassy in Prague 1
Slížková, Zuzana ; Frankeová, Dita ; Viani, Alberto ; Hauková, Petra ; Koudelková, Veronika ; Svoboda, Milan
The aim of the work was to analyze the mortar taken from the Gloriette (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in HCl to determine the mixing ratio.
Chemical and microscopic analysis of external plaster, Petschek villa, V sadech 2, Prague 6
Slížková, Zuzana ; Viani, Alberto ; Koudelková, Veronika ; Frankeová, Dita ; Hauková, Petra
The aim of this work was to analyze mortar from Petschek villa, XRD and SEM-EDX analyzes have been proposed, which results in the characterization of aggregate and mortar binders. The analyses proved gypsum plaster with surface paint.

National Repository of Grey Literature : 16 records found   1 - 10next  jump to record:
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3 KOUDELKOVÁ, Veronika
7 Koudelková, Věra
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