Department of laboratory research on geomaterials
| Doc. Ing. Jiri Scucka, Ph.D. | ||
| Doc. Ing. Ivan Janecek, CSc. Mgr. Ing. Adam Kalbarczyk Dr. Ing. Pavel Konecny Ing. Alena Kozusnikova, CSc. Ing. Lucie Kralova Milan Kraus | Miroslava Krupikova Ing. Lukas Kubina Ing. Katerina Mareckova Prof. Ing. Petr Martinec, CSc. Dr. Deepak Amban Mishra, Ph.D. Renata Papcunova | Ing. Eva Plevova, Ph.D. Mgr. Lucie Ruppenthalova Ing. Lenka Vaculikova, Ph.D. Ing. Vera Valovicova, Ph.D. Prof. Ing. Zdenek Vasicek, DrSc. Ing. Leona Vavro, Ph.D. |
The Department of Laboratory Research on Geomaterials was established as an independent department in 2006 by amalgamating the three laboratories of the Centre for the Research on Earth Materials. The department provides comprehensive material research on geomaterials and selected construction materials. Mineralogy and petrography belong to the general trends of research, where new methodologies of the identification and characterization of materials are being developed in an area based on infrared spectroscopy, on the methods of thermal analysis, optical and confocal microscopy and on image analysis. Among significant scientific areas also belong: stress and strain properties of geomaterials in different states of stress; the changes in the permeability of materials due to the changes of stress conditions; the interaction of materials with water; and thermal properties of geomaterials. The geology of coal basins and geological problems associated with important geotechnical constructions also forms part of the research.
Main research topics
Geology of coal basins. For many years the department has been dealing with problems associated with the geology of coal basins. For the most part, this research topic includes the geological documentation of boreholes and mine workings; sedimentological and lithological analysis of rocks and coal. Considerable attention is focused on the research and identification of correlation horizons in coal basins, the results of which are continuously used, primarily in the correlation of coal seams in the Czech part of the Upper Silesian Coal Basin. In 2008, the monograph Geological environment and geotechnical properties of covering strata of Carboniferous in the Czech part of the Upper Silesian Basin was published. From both a social and economic aspect, another important area of research, in which department personnel have been involved for many years, is the study of the bonding of gases in coal mass and in rocks in connection with the technology of coal bed methane extraction; with the CO2 storage and with the occurrence of gas-dynamic phenomena jeopardizing the safety of work underground. In 2011, the results of this work were published in the monograph Carbon dioxide and rock massif.
Mineralogy and petrography. We provide petrographic and mineralogical analyses of a wide spectrum of both natural and industrial materials for our partners in industry, science, and education. As far as natural rocks are concerned, we deal primarily with the classification of rocks in petrographic systems; with the analysis of rock composition and structure (particle size distribution, grain sorting, roundness and angularity of clastic grains; the identification of carbonates and clay matrix in rock; coal mass in sediments; transformation of rock-forming minerals; normative com-position on the basis of chemical analysis).
We determine the structure, composition, grain, and pore size distribution in industrial materials such as mineral abrasives, micronized particles, and silicate construction materials. We also identify the components and minerals and determine the type and intensity of corrosion and alteration.
Coal petrology includes maceral analysis of coal; determining mineralization in coal, analysis of the deformation of coal before and after deformation tests; micro-hardness and textural analysis of cokes. Department personnel are currently involved in research for the international project of the Research fund for coal and steel: The improve-ment of coal carbonization through the optimization of fuel in coking coal blends - RATIO COAL.
Image processing and analysis of geomaterials and construction materials. For the study of the composition and structural-textural parameters of geomaterials and construction materials, methods of digital image processing and analysis are used and developed in the department. The procedures of image analysis are used mainly to enable the quantification of the composition and structural parameters of material; the analysis of shape, size and orientation of particles; the analysis of the size and distribution of pores; the measurement of intensity and orientation of micro-fracturing, etc. Department personnel have developed many new algorithms and methodologies which have been applied in morphological analysis of geomaterials at different scale levels. For example, they have succeeded in solving what was until now a very difficult analytical problem: the determination of the size and shape of grains and morphological anisotropy in thin sections of carbonate rocks (microscopic scale). The methodology of the evaluation of the morphology of aggregate grains for construction purposes has been prepared and verified (mesoscopic scale), which enables the description and quantification of the morphometric parameters of aggregate grains in relation to the orientation of mineral grains and micro-fracturing in rock and their use in modelling in civil engineering and geotechnics. Furthermore, the methodology for the quantification of structural-textural parameters of underground working faces has been developed as part of a geotechnical survey in the underground engineering (macroscopic scale). This makes possible a significant improvement in the knowledge from the investigation of a working face, while simultaneously eliminating safety risks.
Research on physical properties of geomaterials. The other area of research is the study of the effect of thermo-hydro-mechanical processes on physical properties of geomaterials, such as mass and volume density; absorptive capacity; water absorption; ultrasonic wave velocity; thermal conductivity; specific thermal capacity; and thermal expansion. The strength and strain properties are estimated in laboratory tests of compression strength and tensile strength, where the Young modulus, Poisson’s ratio, under the uniaxial and triaxial state of stress and the ultrasonic wave velocity in the deformation process are determined. The results of triaxial tests are further utilized in the construction of Mohr’s criteria. Special attention is paid to the study of the permeability of rocks and coal in the triaxial state of stress.
Particular attention is paid to the study of rocks and coal permeability in triaxial state of stress. The measuring equipment consists of a triaxial cell KTK 100, modified for gas passage. The confining pressure is applied by the pressure of hydraulic oil up to a maximum value of 100 MPa. The source of axial stress is a computer controlled mechanical press ZWICK 1494, with a maximum force of 600 kN. Usually, nitrogen is used as a gas medium for the permeability measurement. The effect of different parameters on the permeability of rock and coal under the triaxial stress state is studied; structure, anisotropy and composition; the increase of hydro-static pressure; the increase of axial stress and temperature.
Extensive series of sedimentary carboniferous rocks and coals have already been tested by the methodology for the measurement of permeability developed by department. In recent years, research has been focused on granitic rocks from important localities in the Czech Republic. Within the RDIOP project Institute of Clean Technologies for Mining and Utilization of Raw Materials for Energy Use, the department obtained new sophisticated hydraulic equipment, MTS, for the mechanical testing of rocks. The acquisition of this equipment enables the department to conduct a wide spectrum of tests of mechanical properties, including, for example, determining the fracture toughness of rocks or measuring the permeability of rocks for liquids.
Research on clay minerals. The issue of clay minerals has been studied by our department for many years. In close cooperation with the VSB – Technical University of Ostrava and the University of Ostrava, research into nano-materials based on clay minerals is already in progress; the study of the thermal stability of laboratory prepared composite materials; and the development of the possibilities of the application of the FTIR and Raman spectroscopy for the identification and quantification of clay minerals in rocks. The reason for the continuing interest in clay minerals is their remarkable capability to absorb organic or inorganic compounds into their crystal structure. With the exception of their traditional role as sorbents, clay minerals represent a means in the development of materials with predefined properties: the so called nano-composites. The knowledge gained about the properties of nano-composites prepared in this way, contributes to the solution of current problems associated with the preparation of sorbents for the removal of substances from various environmental burdens with the formation of barriers for depositing waste, or the reinforcement and stabilization of soils with a high content of clays and humic substances.
The application of thermal analysis is also being developed in the department with the study of sorption and mechanical properties of clay mineral and modified clays. Within the study of thermal stability of prepared composite materials, a comprehensive database of thermal curves of clay minerals, their admixtures and selected types of sedimentary rocks has been prepared. For the most part, the changes of weight dependent on temperature and time, with optional adjustment of experimental atmosphere (oxidation, inert atmosphere), including a high vacuum, are evaluated. The temperature of dehydration, dehydroxylation and transformations of individual minerals and kinetic parameters of running reactions are also determined. Thanks to advanced kinetic software, we can also predict the process of reaction and thermal stability of material in an optional temperature mode.
A further trend in research is the application of FTIR and Raman spectroscopy to the qualitative and quantitative analysis of clay minerals in rocks, primarily in those areas where the presence of clay minerals significantly affects the physical and chemical properties of rocks – in geomechanics, when ensuring the slope stability, in the solution of problems regarding the construction and stability of underground construction and in many other fields when the Earth’s crust is to be affected. In recent years, attention has been focused on the utilization of statistical multivariation methods in the analysis of infrared spectra of minerals and rocks. With just the combination of the FTIR spectroscopy and statistical methods, it is possible to obtain faster and more reliable results in the determination of individual minerals in rocks. The results of this research have been prepared within the research programmes of several grant projects between 2003 and 2010, with the results continuously published in the relevant journals.
Research on concrements of urinary tract. For many years, our department has also been dealing with the mineralogical analyses of concrements of the urinary tract of patients from the Ostrava region. This unique research takes place in collaboration with the department of clinical biochemistry of the Municipal Hospital in Ostrava and the data of more than 14,000 patients have been investigated to date. Not only are mineralogical analyses utilized, but also the analyses of trace elements content and the synchrotronic micro-CT tomography on lump samples. This research shows how complicated the inner structure of concrement, which originated in the dynamic environment of the human body, actually is. It was found out that urinary calculi of patients from the Ostrava agglomeration contain 130 mineral combinations, while the Ca–oxalate and Ca,Mg-phosphate concrements are completely dominant. The results of the long-term research have been prepared within the project of the GA CR in 2009 - 2011. A co-researcher in the project was the Faculty of natural sciences of Masaryk University in Brno. The results are published continuously in important European urological journals. The adoption of a new methodology of mineralogical analysis of concrements in the Czech Republic (based on the IR spectroscopy, optical microscopy and micro-chemical methods) was emphasized also in the book by K. Jiřík et al. The Municipal Hospital of Ostrava in transformations of time (2002).
Study of slag and geopolymers. Analytical procedures used in our department are also applied in finding out the causes of volume changes of backfilling slag and metallurgical ceramics that cause extensive damage to construction in the Ostrava region. This damage, which appeared in the period after 2000, is a serious social and economic problem.
Metallurgical slag found during archaeological explorations is studied as well. The identification of slag types contributes to the understanding of the circumstances relating to technologies used in the constructions under archaeological investigation. For example, the results of the work were published in 2011, within the framework of the monograph St. Martin Church in Bohusov. Geopolymers (i.e. alkali activated granulated furnace slag) belong to new progressive building binders. The research carried out in collaboration with FMME VSB-TUO deals with their micro-texture and structure of pores and with the origin of new mineral phases in geopolymer with granulated slag and with different portions of milled fly ash and with the use of liquid and solid alkali activators. The research personnel succeeded in developing new types of geopolymers with more stable mineral phases in a dense structure of geopolymer.
Structure and properties of geocomposite materials. Over a considerable period, the department has dealt with unique research into the structure and properties of geocomposites – specific materials created by pressure grouting of chemical grouts into soils, disturbed rocks or into disturbed building constructions. The research is carried out in collaboration with the department of geomechanics and mining research and primarily includes the development and application of methodologies for the visualization of the geocomposite structure; the quantification of structural-textural parameters; the study of relationships between the material structure and its physical-mechanical properties and the evaluation of thermal stability of chemical grouts in geotechnical or building constructions. Special attention is paid to important anomalies in the structure of geocomposite monoliths created during the particular geotechnical applications and to their effect on the behaviour of material in the construction.
Other information
|
Recently solved projects ( PDF, 207 kB )
Selected publications ( PDF, 220 kB ) |