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  • 1.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Free mica in crushed rock aggregates2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Free mica particles in crushed rock aggregates for constructional purposes affect the quality of the end product. It is also known that mica-bearing rocks may cause damages of the road constructions, especially in regions with a temperate climate. The negative influence arises in both bounded and unbounded layers. The deterioration of the construction is related to the ability of mica particles to be released during crushing and to concentrate in the aggregate fine fractions. As the free mica particles absorb and hold liquid such as bitumen and water, the unbounded base course becomes susceptible to frost weathering and the mechanical properties of the asphalt mixture are negatively influenced. The water absorption ability is in turn caused by an increased specific surface area of the fine fraction depending on the grain shape of mica particles and their intra crystalline cavities. The aim of the present study was to investigate, emphasise, and contribute to an understanding of the performance of free mica particles in the fine fractions of crushed rock aggregates. The free mica problems are well- known, but sparsely taken into account in projecting and prospecting activities. The mineralogical composition (i.e. the quality) of the rock material is often a subordinated task in early stages in planning for roads and railways. Connected with establishment of quarries the estimation of rock materials quality is generally based on petrographic and mechanical analyses of drill-cores.The study presented consists of: * The investigation of the ability of free mica particles to enrich in fine fractions of granitoid crushed rock aggregates. The comparison study to examine a possible correlation between the content of mica in original rock materials, the content of free mica particles in rock aggregate products, and the content of free mica particles in drill cuttings. * The development of a method to estimate free mica particles in aggregate fine fractions using image analysis of grain mounts. * The development and practical applicability of a method to estimate rock aggregates quality using analyses of drill cuttings. The study reveals that mica-bearing rocks exposed to mechanical impact release free mica particles that concentrate in the fine fractions of crushed rock aggregates. The original grain size of mica in the host rock is suggested to influence on the process. Coarse-grained rocks seem to separate free mica grains in earlier phases of the crushing process than fine-grained ones. The enrichment is suggested to depend on the textural characteristics of the rock rather than on the mineralogical composition. These aspects must be taken into consideration when the grain size fractions for analyses of free mica content are selected. The statistical evaluation of the new method for estimation of free mica particles points out its certainty and repeatability. Due to the possibility to save the images of the statistical operation, the results of the method are controllable. These factors mentioned make the method satisfactory and statistically acceptable from a scientific point of view. The concept using drill cuttings for estimation of rock aggregates quality is practically tested and evaluated as an effective field method. The further development and calibration should focus on improvement of sampling concerning the content of coarse drill cuttings. The homogeneity/heterogeneity of the bedrock is crucial for the selection of the samples and stresses the necessity of representative sampling.

  • 2.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Kartläggning av teknologi och ingenjörshjälpmedel för bergmaterialproduktion2003Report (Other academic)
    Abstract [sv]

    Inom bergmaterialindustrin har en rad forskningsresultat och andra hjälpmedel presenterats med avsikt att effektivisera och optimera produktionen. Många av dessa verktyg har ännu inte kommit till praktisk användning i den omfattning som är önskvärd i syfte att förbättra företagens och branschens lönsamhet, höja produktkvaliteten och stödja en långsiktig, hållbar utveckling. Projektets målsättning har varit att göra en övergripande kartering över ny teknik och senaste forskningsresultat samt befintlig praxis. Ett andra mål har varit att lämna rekommendationer för snabbare införande av nya tekniska rön. Utredningen baseras på litteraturstudier och intervjuer med erfarna människor från branschen, konsulter och leverantörer inom alla ingående delprocesser samt studiebesök vid utvalda referensanläggningar. För att möjliggöra en schematisk framställning och en systematisk arbetsgång har studien utgått ifrån bergmaterialkedjans processflöde, vilket har indelats i följande sju teknikområden: prospektering av nya täkter, losshållning inklusive planering av täktverksamhet, krossnings- och siktningsprocessen, lastning och transport i täkt, upplagshantering samt provtagning och provning, transport till kund, användningsområden, produktutveckling och restprodukter, kunskapsöverföring mellan processtegen. Arbetet redogör för verktyg och hjälpmedel, befintlig praxis, svensk aktuell forskning och senaste forskningsresultat samt relevant litteratur inom varje delprocess. Ny teknik faller under verktyg och hjälpmedel och med befintlig praxis avses en beskrivning av graden för tillämpning. Bland ändamålsenliga hjälpmedel, vars användning ännu inte är vedertagen, kan nämnas MWD-teknik, geofysiska metoder, bildanalys, automatisk processtyrning, laserscanning samt trådlös kommunikation. Införandet av modern teknik kan förfalla gå långsamt, men eftersom branschens investeringar är stora och avskrivningstiderna är långa måste den låga förnyelsehastigheten ges viss förståelse. Därtill måste investeringarna vara kostnadseffektiva i förhållande till anläggningens produktionsvolym, vilken i sin tur är relaterad till avsättning. Forskningsresultat upplevs många gånger vara komplicerade att tolka och det akademiska språket i kombination med avancerade beräkningar möts av tvivel om huruvida resultatet är tillämpbart i praktiken. Innan forskningsresultat ska implementeras bör de följaktligen dels anpassas till rådande produktionsförutsättningar, dels förmedlas med ett tydligt, enkelt branschspråk. Det innebär att teoretiska hypoteser och belägg måste översättas till praktisk verksamhet när de presenteras för branschen. Andra angelägenheter av mer allmän karaktär som har framkommit under studien är bland annat efterlysning av ett tydligt geologiskt språk, en enhetlig tolkning av regelverk, ett relativt stort rekryteringsbehov under kommande år, större krav på omfattningen av återvinning och återanvändning samt allmänhetens bristande kunskaper om bergmaterialets betydelse för samhälle och infrastruktur.

  • 3.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Technological properties of rock aggregates2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The commission of technical geology is to apply geological knowledge to the field of constructional engineering, mining technology, environmental protection, architecture etc. The sector of infrastructure is highly dependent on the production of crushed rock materials as the main constituent of e.g. road and railway constructions. The functional properties of crushed rock materials used are of major importance concerning the durability of the construction and they are strongly connected to economic and environmental consequences. The quality of the aggregates is the crucial agent to reach the optimal performance of the infrastructural network. Due to the geological, geographic and climatologic preconditions of Northern Scandinavia, the quality of crushed rock materials is even more important. The Fennoscandian bedrock is dominated by igneous and metamorphic rocks. The access to qualitative rocks for production of aggregates displays considerable regional variation. The oblong geographical extension of the North Scandinavian countries, the fairly low population and the frequent traffic require the widespread infrastructure. The temperate climate characterized by freeze-thaw cycles combined with usage of studded tyres requires a long lasting construction of high sustainability.In spite of available international standards dealing with the aggregates’ quality, the deterioration of the road constructions is noted in Sweden; it is mostly caused by use of mica-rich, heterogeneous rocks. The utilization of these kinds of rock materials as base courses and bituminous wearing courses results in economic losses and negative environmental consequences.The aim of the present thesis was to study technological properties of aggregates in a challenge to connect them with the petrographic characteristics of rock materials. The study includes an investigation of enrichment of free mica particles in fine fractions originating from crushed rock aggregates and the development of a scientifically based method for estimation of free mica particles in aggregate fine fractions. The second part of the thesis deals with the influence of petrographic parameters on the mechanical (functional) properties of aggregates. Finally, an interlinking method of drill cuttings analysis is applied as a tool for estimation of rock aggregates’ quality and usability.The studies of mica confirmed the enrichment of free mica particles in fine fractions of the crushed rock compared with initial mica content in the rock. The primary grain size of mica in the host rock is suggested to influence the process of enrichment. The evaluation of the developed method for estimation of free mica particles confirms its certainty and repeatability. The petrographic analyses of drill cuttings indicated the compatibility between the content of free mica in fine fractions originating from crushed rock and drill cuttings respectively.The literature review concerning the correlations between petrographic and mechanical properties of rock materials indicated the necessity to intensify the research on this field. Mineralogical composition, micro-cracks, porosity, grain size, grain shape and the degree of foliation were found to be the most important petrographic parameters influencing the mechanical and technical properties of igneous, metamorphic and sedimentary rocks. The study of the petrographic characteristics of granitoid and gabbroid intrusive rocks as a tool for evaluation of mechanical properties confirmed that grain size, content of mica and frequency of micro-cracks are the main petrographic variables influencing mechanical properties of granitoids. In the case of gabbroid rock types, the mechanical properties generally respond to the mica content and frequency of micro-cracks.The results of the study of the petrographic and mechanical properties of the rock materials point to the possibility to develop a system for estimation of the mechanical properties of rock materials using their petrographic characteristics.

  • 4. Johansson, Eva
    et al.
    Lindqvist, Per-Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sammanställning av metoder för beskrivning, provning och klassificering av berg2003Report (Other academic)
  • 5.
    Johansson, Eva
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Loorents, Karl-Johan
    VTI - Statens väg-och transportforskningsinstitut.
    Miskovsky, Karel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    A method for estimation of free mica particles in aggregate fine fraction by image analysis of grain mounts2007Conference paper (Other academic)
  • 6.
    Johansson, Eva
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Miskovsky, Karel
    Project: Estimation of rock aggregate quality in the road alignment by using drill cuttings analysis - by using drill cuttings analysis2010Other (Other (popular science, discussion, etc.))
    Abstract [en]

    The drill cuttings method is used for qualitative evaluation of rock aggregate in the road alignment during the road project stage

  • 7.
    Johansson, Eva
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Miskovsky, Karel
    Envix Nord AB, Umeå.
    Bergknut, Magnus
    MTC, Umeå.
    Sachlova, Sarka
    Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Prague.
    Petrographic characteristics of intrusive rocks as an evaluation tool of their technical properties2016In: Sustainable use of traditional geomaterials in construction practice, Geological Society of America, 2016, p. 217-227Chapter in book (Refereed)
    Abstract [en]

    The main petrographic variables of intrusive rocks that influence the technical test methods common used within the aggregate industry were identified and evaluated, the aim being to investigate whether petrographic description could be used as a tool for the preliminary quality evaluation of different rock groups. Evaluation of the dependence of the technical test methods on petrographic variables covered 26 intrusive rocks, including some of their altered varieties (orthogneisses), divided into two groups: 17 granitoids and 9 gabbroids. The selective designated samples were analysed to determine their petrographic characteristics and resistance to fragmentation, wear and wear by abrasion from studded tyres. In order to identify the complicated associations between the petrographic and technical properties, multivariate statistical evaluation was performed. The results of statistical evaluation highlighted that mean grain size of mica minerals, grain size distribution, content of mica minerals and mean grain size were the main variables influencing the technical properties of granitoid rocks, while for gabbroid rocks, the main influences were the frequency of microcracks, mica content, grain size distribution and mean grain size.

  • 8.
    Johansson, Eva
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Miskovsky, Karel
    Loorents, Karl-Johan
    Swedish Road Administration.
    Estimation of rock aggregates quality using analyses of drill cuttings2009In: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 18, no 3, p. 299-304Article in journal (Refereed)
    Abstract [en]

    There is a need for an effective method to estimate the quality of crushed rock aggregates and its usability in the early stages of project planning, e.g., for road and railway constructions and quarry prospecting. The proposed method is based on mineralogical and petrographic analyses of drill cuttings and analysis of the coarse fraction to estimate the homogeneity/heterogeneity of the bedrock. The geological analyses are followed by an estimation of the rock materials' mechanical properties and their potential technical usability. Development and practical applicability (field and laboratory) of the method have been performed and correlated to three road projects from regions of different geological and climatic zones in Sweden. The study confirms the capability of the proposed method as a surveying tool.

  • 9.
    Johansson, Eva
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Miskovsky, Karel
    Loorents, Karl-Johan
    VTI - Statens väg-och transportforskningsinstitut.
    Löfgren, Ola
    Ekovision nord, Vindeln.
    A method for estimation of free mica particles in aggregate fine fraction by image analysis of grain mounts2008In: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 17, no 2, p. 250-253Article in journal (Refereed)
    Abstract [en]

    The need to evaluate free mica grains in fine fraction of aggregate products has initiated the development of a statistically and scientifically acceptable method. The proposed method is based on a modified point-counting approach using digital micro photos of thin sections of aggregate grains and a software package to sustain sample analysis. A thin section of aggregate grains provides permanent sample documentation readily available for complimentary or other analysis. Statistical analysis, together with a repeatable analysis of samples (permanent mounts), confirms the robustness of the method. The method is appropriate as a complementary assessment tool to estimate and trace changes or variations in quality of rock aggregate. Though, the estimation of free mica particles in fine fraction needs to be combined with other analyses, e.g., petrographic analysis and analyses of mechanical properties, to assess the quality of any rock material. As the samples can be collected from drill cuttings, i.e., an accessible residual product obtainable from surveying or production, the present method is particularly useful as a surveying tool and in prospecting and projecting activities.

  • 10. Lindqvist, Per-Arne
    et al.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Bergets inverkan på praktisk produktionsoptimering2005Report (Other academic)
  • 11. Lindqvist, Per-Arne
    et al.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Kartläggning av produktionsoptimering: studiebesök och fallstudier2004Report (Other academic)
  • 12. Lindqvist, Per-Arne
    et al.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Metoder för design och simulering vid produktionsoptimering2005Report (Other academic)
  • 13.
    Loorents, Karl-Johan
    et al.
    VTI - Statens väg-och transportforskningsinstitut.
    Johansson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Arvidsson, Håkan
    VTI - Statens väg-och transportforskningsinstitut.
    Free mica grains in crushed rock aggregates2007In: Bulletin of Engineering Geology and the Environment, ISSN 1435-9529, E-ISSN 1435-9537, Vol. 66, no 4, p. 441-447Article in journal (Refereed)
    Abstract [en]

    Enrichment of free mica (i.e. as monomineralic grains) in the fine fraction of crushed rock aggregates affects the quality of the aggregate end product. Granitoid rock from the Svecofennian Province were used as being representative of crushed rock aggregates commonly used for construction purposes. The results reveal a general trend of enrichment of mica for finer fractions. For the coarse grained rock a peak occurs at 0.25-0.5 mm followed by a decrease in the amount of free mica; for grains <0.063 mm there is an increase. The general trend and peak are correlated to the microstructural characteristics of the samples.

1 - 13 of 13
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