Papers by Kateřina Kovářová
SPACE International Journal of Conference Proceedings, Jul 24, 2022
Staletá Praha, Dec 14, 2021
Advances in intelligent systems and computing, Sep 30, 2017
The sandstone internal structure is one of the most important factors controlling mechanical prop... more The sandstone internal structure is one of the most important factors controlling mechanical properties of this stone. There are many methods enabling study of the properties and character of the internal structure. The known methods are based on the penetration of a chosen medium of a detected volume into the pores or they are based on image analysis of rock slices, where fluorescent colouring highlights the pores. Unfortunately, these methods have a destructive character and, therefore, it is not possible to use the stone samples again. The possibility to re-use the samples makes the micro-CT a very useful tool. Interpretation of the micro-CT results in combination with the results of other methods may enable more detailed view into the internal structure. We studied widely used Czech sandstones using the micro-CT in the course of our experiment. Next, the acquired data was evaluated in commercial software VGStudio MAX 2.2 and also in our FOTOMNG system. We implemented new specialized module in this system for evaluating of such data. For a measurement we prepared several image preprocessing methods. This preprocessing is consisted for example from image binary thresholding for a better diversity between inner porosity and sandstone itself or colour inversion. As addition we implemented function for cropping the samples, due to depreciation of the sample borders caused by repeated measurement. We are able to calculate the value of porosity, for whole series a volume of porespace of sandstone samples or other statistical values. Results and limitations of interpretability are discussed in this article.
Key Engineering Materials, Aug 1, 2018
: The paper is focused on a system of investigation of hidden parts of historical buildings as fo... more : The paper is focused on a system of investigation of hidden parts of historical buildings as footing masonry and subsoil affecting significantly their technical conditions and stability. These impacts are mostly difficult to identify in time and there are often indirect producing differential settlement resulting in development of systems of cracks in the building masonry. Reliable analysis of the building supporting system shall precede any remedial actions or reconstructions. If the demonstration of the above negative impacts on the building becomes visible, it can indicate our late entry in to solving the problems with deterioration of the foundation system. Investigation boring and instrumentation of boreholes for high accuracy 3D displacement monitoring with local levelling system is presented in the paper illustrated by an example of one baroque church of the Broumov group of churches. This activity was followed by analyses of building stones and determination of degree of the footing masonry and subsoil deterioration together with careful input data for numeric modelling estimation.
Advanced Materials Research, Apr 1, 2014
The aim of the contribution is to present the results of research focused on cement mineralogical... more The aim of the contribution is to present the results of research focused on cement mineralogical composition changes and their influence on physical-mechanical properties of sandstones. Three types of Czech sandstones were tested during this experiment Hořice, Kocběře and Božanov. The sandstone samples were treated in the climatic chamber in order to simulate weathering processes that are typical for winter period in Prague. The influence of road salts was also taken into consideration. For the purposes of mineralogical changes determination the sandstone cement was separated and subsequently analyzed using X-Ray diffraction a DTA/TG analysis. The physical-mechanical properties such as e.g. uniaxial compressive strength, water absorption and open porosity were determined before and after the climatic treatment to enable evaluation of the influence of weathering processes.
The sandstone internal structure is one of the most important factors controlling mechanical prop... more The sandstone internal structure is one of the most important factors controlling mechanical properties of this stone. There are many methods enabling study of the properties and character of the internal structure. The known methods are based on the penetration of a chosen medium of a detected volume into the pores or they are based on image analysis of rock slices, where fluorescent colouring highlights the pores. Unfortunately, these methods have a destructive character and, therefore, it is not possible to use the stone samples again. The possibility to re-use the samples makes the micro-CT a very useful tool. Interpretation of the micro-CT results in combination with the results of other methods may enable more detailed view into the internal structure. We studied widely used Czech sandstones using the micro-CT in the course of our experiment. Next, the acquired data was evaluated in commercial software VGStudio MAX 2.2 and also in our FOTOMNG system. We implemented new special...
Key Engineering Materials, 2018
: The paper is focused on a system of investigation of hidden parts of historical buildings as fo... more : The paper is focused on a system of investigation of hidden parts of historical buildings as footing masonry and subsoil affecting significantly their technical conditions and stability. These impacts are mostly difficult to identify in time and there are often indirect producing differential settlement resulting in development of systems of cracks in the building masonry. Reliable analysis of the building supporting system shall precede any remedial actions or reconstructions. If the demonstration of the above negative impacts on the building becomes visible, it can indicate our late entry in to solving the problems with deterioration of the foundation system. Investigation boring and instrumentation of boreholes for high accuracy 3D displacement monitoring with local levelling system is presented in the paper illustrated by an example of one baroque church of the Broumov group of churches. This activity was followed by analyses of building stones and determination of degree of the footing masonry and subsoil deterioration together with careful input data for numeric modelling estimation.
Advances in Intelligent Systems and Computing, 2017
The sandstone internal structure is one of the most important factors controlling mechanical prop... more The sandstone internal structure is one of the most important factors controlling mechanical properties of this stone. There are many methods enabling study of the properties and character of the internal structure. The known methods are based on the penetration of a chosen medium of a detected volume into the pores or they are based on image analysis of rock slices, where fluorescent colouring highlights the pores. Unfortunately, these methods have a destructive character and, therefore, it is not possible to use the stone samples again. The possibility to re-use the samples makes the micro-CT a very useful tool. Interpretation of the micro-CT results in combination with the results of other methods may enable more detailed view into the internal structure. We studied widely used Czech sandstones using the micro-CT in the course of our experiment. Next, the acquired data was evaluated in commercial software VGStudio MAX 2.2 and also in our FOTOMNG system. We implemented new specialized module in this system for evaluating of such data. For a measurement we prepared several image preprocessing methods. This preprocessing is consisted for example from image binary thresholding for a better diversity between inner porosity and sandstone itself or colour inversion. As addition we implemented function for cropping the samples, due to depreciation of the sample borders caused by repeated measurement. We are able to calculate the value of porosity, for whole series a volume of porespace of sandstone samples or other statistical values. Results and limitations of interpretability are discussed in this article.
15th International Multidisciplinary Scientific GeoConference SGEM2015, SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, 2011
Building stone is during its “life” influenced by actions of weathering processes which usually l... more Building stone is during its “life” influenced by actions of weathering processes which usually lead to changes in the internal structure of the stone which influences its durability. For this reason, studies of a stone internal structure are very important. There are many methods to determine effective porosity and provide porosity values in a percentage, nevertheless, these methods do not enable visualization of the internal structure. The visualization can be useful for better understanding of the durability phenomenon. Therefore, the methods of X-Ray microtomography and microscopy in ultraviolet light were used in our research of three Czech sandstones. Both methods also provide different values of porosity which are given due to their limitation. The main aim of this contribution is to present basic information about both methods and to compare their results, advantages and disadvantages.
The aim of the introduced contribution is to present the methodology for the research and mainten... more The aim of the introduced contribution is to present the methodology for the research and maintenance of facing ashlars of historical structures. The natural building stone of historic monuments is subjected to various types of deterioration and damages mostly due to weathering processes. If the stone has to be completely changed during the reconstruction, it should be preferentially replaced by variety of the same lithological composition, the same or similar appearance and with the sufficient durability. It is methodologically necessary to generate the ashlars façade plan based on digital photographic procedure in the real scale before the restoration. The aim of this paper is to bring a modern look for the processing, visualization and storage of information obtained in mapping facades of historic buildings. The data processing and their storage in GIS were implemented on the façade of St. Martin's Cathedral in Bratislava. There are also described the basic processes of stone...
After the controversial discussion which accompanied a recent repair of the Charles Bridge in Pra... more After the controversial discussion which accompanied a recent repair of the Charles Bridge in Prague an interdisciplinary team was given the task of summarizing the technical, technological and conservation requirements for the selection and processing of the replacement stone intended for ashlar masonry repairs. Geologists, structural engineers, construction historians, conservationists and restorers joined together to give their views on the relevant intensity of interventions, the replacement stone quality and also the parameters of processing by craftsmen. Methodical guidelines should define the necessary level of adequate historical, technological and structural surveys and, subsequently, propose an optimal procedure for laboratory tests and for the following repair processes of a particular structure. A focus on the influence of the finishing tools to the look and durability of the stone surface is among the most innovative aspects. Concurrently the practical usefulness of the...
Sandstones were often used mainly as building material in Prague. Weathering processes lead to de... more Sandstones were often used mainly as building material in Prague. Weathering processes lead to deterioration of these dimension stones and to changes in their durability. The range of the deterioration depends on petrography, including internal structure, mineral and matrix composition, and also changes initiated. The stone’s properties are negatively influenced especially during the winter frost period, and the presence of salt can exacerbate this process. The national standardized testing methods for natural stone, such as determination of frost resistance and determination of resistance to salt crystallisation may not take into consideration the actual conditions in the stone’s locality. Road salts, mainly composed of sodium chloride, are used to de-ice streets in Prague during winter season. Samples of snow/water mixtures from Prague city centre were chemically analyzed and the average NaCl concentration was determined. To simulate the weathering processes typical in Prague’s wi...
13th SGEM GeoConference on SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, 2013
Advanced Materials Research, 2014
The aim of the contribution is to present the results of research focused on cement mineralogical... more The aim of the contribution is to present the results of research focused on cement mineralogical composition changes and their influence on physical-mechanical properties of sandstones. Three types of Czech sandstones were tested during this experiment Hořice, Kocběře and Božanov. The sandstone samples were treated in the climatic chamber in order to simulate weathering processes that are typical for winter period in Prague. The influence of road salts was also taken into consideration. For the purposes of mineralogical changes determination the sandstone cement was separated and subsequently analyzed using X-Ray diffraction a DTA/TG analysis. The physical-mechanical properties such as e.g. uniaxial compressive strength, water absorption and open porosity were determined before and after the climatic treatment to enable evaluation of the influence of weathering processes.
Advanced Materials Research, 2013
The aim of the contribution is introduce the role of the geologist in the process of the restorat... more The aim of the contribution is introduce the role of the geologist in the process of the restoration of monuments ashlars masonry. Within the frame of our project, we participate on the reconstruction of battlements of the castle Kost, which were built predominantly from sandstones. These stones undergo to weathering processes and so they are damaged. Therefore, it has been necessary to restore and even change some blockstones. In cooperation with the experts from other branches, especially restorers and preservationists, the building blocks suitable for exchange were selected and the new replacement rock material was chosen. As it is obvious from the process of this reconstruction, the participation of geologists is indispensable.
SGEM2012 12th International Multidisciplinary Scientific GeoConference, 2012
ABSTRACT Weathering processes lead to deterioration of dimension stones and to changes in their d... more ABSTRACT Weathering processes lead to deterioration of dimension stones and to changes in their durability. The range of the deterioration depends on petrography, including internal structure, mineral and matrix composition, and also changes initiated. The stone's properties are negatively influenced especially during the winter frost period. The presence of salt can exacerbate this process. The Czech national standardized testing methods for natural stone, such as determination of frost resistance and determination of resistance to salt crystallisation, may not take into consideration the actual conditions in the stone’s locality. This paper is focused on the description of an alternative procedure of stone durability determination and on the evaluation of induced changes. To simulate the weathering processes typical in Prague’s winter climatic conditions, seasonal data from 1999 to 2008 were statistically analyzed. Samples of snow/water mixtures from Prague city centre were chemically analyzed to determine the average NaCl concentration. Three Cretaceous sandstones - Božanov, Hořice and Kocbeře - were tested during this experiment. Developed changes in the internal structure were studied using Hg porosimetry. Physical-mechanical properties, such as water absorption at atmospheric pressure, uniaxial compressive strength, apparent density and open porosity, were also studied.
European Journal of Remote Sensing
Buildings, Feb 6, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Acta Polytechnica, Dec 31, 2022
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Papers by Kateřina Kovářová