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  • 51.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    Borehole KLX12A. Normal loading and shear tests on joints. Oskarshamn site investigation2006Rapport (Fagfellevurdert)
  • 52.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    Borehole KLX13A. Shear tests on sealed joints. Oskarshamn site investigation2006Rapport (Fagfellevurdert)
  • 53.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    Äspö Pillar Stability Experiment. Samples from TASQ tunnel at Äspö HRL. Normal loading and shear tests on joints2005Rapport (Fagfellevurdert)
  • 54.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Andersson, Lars
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Appelquist, Karin
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Normal Loading and Shear Tests on Rock2016Rapport (Annet vitenskapelig)
  • 55.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Andersson, Lars
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Appelquist, Karin
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Normal Loading and Shear Tests on Rock Joints from Olkiluoto2016Rapport (Annet vitenskapelig)
  • 56.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Brzovic, Andres
    de los Santos, Carlos
    Direct shear and tensile test on cemented healed joints from El Teniente mine, Chile2011Inngår i: Proceedings of the 12th ISRM International Congress on Rock Mechanics, 2011, , s. 649-654Konferansepaper (Fagfellevurdert)
  • 57.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Jansson, Thomas
    Christiansson, Rolf
    Measurement of micro crack volume in low porosity crystalline rock2007Inngår i: Proceedings of the 11th ISRM Congress, 2007Konferansepaper (Fagfellevurdert)
  • 58.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Johannesson, Pär
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Lindqvist, Jan-Erik
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Brander, Linus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Schouenborg, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    ONKALO POSE Experiment - Geological and Rock Mechanical Tests on Samples from a Heating Test at Olkiluoto2016Rapport (Annet vitenskapelig)
  • 59.
    Jacobsson, Lars
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Larsson, Jörgen
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Direct shear tests on large natural and artificially induced rock fractures in a new laboratory equipment2023Inngår i: Proceedings of the ISRM 15th International Congress on Rock Mechanics and Rock Engineering & 72nd Geomechanics Colloquium: Challenges in Rock Mechanics and Rock Engineering / [ed] Schubert, W. & Kluckner, A., Salzburg: Austrian Society for Geomechanics , 2023, s. 2709-2714, artikkel-id 1827Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A direct shear equipment for testing rock fractures up to 400×600 mm size, and up to 5 MN force in both normal and shear loading directions, was developed. Normal loading and direct shear tests under constant normal stiffness (CNS) and constant normal load (CNL) conditions were conducted on 300×500 mm specimens, one planar steel joint and two natural and two tensile induced rock fractures. Design targets, e.g. system to maintain undisturbed fractures up to testing and high system stiffnesses to achieve well-controlled shear tests, were verified by the experiments. A new optical system for local deformation measurements was used to accurately determine fracture displacements besides conventional non-local deformation measurements. The determined normal stiffnesses were similar previous results from the literature on smaller fractures, whereas the shear stiffness data are novel. The results provide a new insight into processes at the onset of fracture slip.

  • 60.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Schouenborg, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Grelk, Bent
    Smits, Arwen
    Expert System for Dimensioning of Facade Cladding2010Inngår i: Proceedings of Global Stone Congress 2010, 2010, , s. 1-4Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Proceedings of the Global Stone Congress 2010, Alicante Spain, 2-5 March 2010 2010 (Extern vetenskaplig bok)

  • 61.
    Jacobsson, Lars
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Larsson, Jörgen
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Mas-Ivars, Diego
    Svensk Kärnbränslehantering AB, Sweden; KTH Royal Institute of Technology, Sweden.
    Kasani, Hossein A
    Nuclear Waste Management Organization, Canada.
    Johansson, Fredrik
    KTH Royal Institute of Technology, Sweden.
    MEKANISKA EGENSKAPER HOS STORABERGSPRICKOR2024Konferansepaper (Annet vitenskapelig)
    Abstract [sv]

    Experimentella undersökningar av skjuvegenskaperna hos bergsprickor i hårt berg har generellt fokuserat på mindre sprickprover för normalspänningar på upp till 20 MPa, representativa för ett kärnbränsleförvar på ca 400 meters djup. Vid stora sprickprover har skjuvegenskaperna generellt bestämts för låga spänningar, på någon eller några MPa. För att få en förståelse för inverkan av sprickornas storlek för skjuvegenskaperna vid höga normalspänningar är det avgörande att genomföra skjuvförsök på stora bergsprickor (> 200 mm) i hårt berg under höga normalspänningar. I projektet Parameterization of Fractures, POST (2014–2016), studerades skaleffekterna genom in situ-försök, småskaliga skjuvförsök och beräkningssimuleringar. Det konstaterades att laboratorieexperiment under kontrollerade förhållanden och på stora bergprover är nödvändiga för att få tillförlitliga resultat. Det konstaterades också att in-situ-försök är komplexa med stora underliggande osäkerheter och är samtidigt kostsamma. I det pågående projektet POST 2 som startade 2017 har bergsprickor på upp till 500 mm provats i en ny unik laboratorieutrustning, jämte provning av mindre sprickor, vid höga normalspänningar för både CNL och CNS förhållanden och med ny mätteknik. Teknik för att tillverka replikaprover av bergsprickor har utvecklats och provats med syfte att göra lastparameterstudier. Kvaliteten hos geometriavbildningen hos replikaproverna och sprickornas geometrier har uppmätts med högupplöst skanning. I denna artikel presenteras en del av resultaten från projektet. Resultaten från projektet är tillämpbara för andra områden med undermarkskonstruktioner såsom projektering av tunnlar och bergrum för infrastrukturprojekt och gruvor.

    Fulltekst (pdf)
    fulltext
  • 62.
    Jacobsson, Lars
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Sandström, Johan
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Sjögren, Torsten
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Brander, Linus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    ONKALO POSE Experiment - Laboratory Determination of Density, Porosity and Mechanical Anisotropy of Gneiss and Granite2016Rapport (Annet vitenskapelig)
  • 63.
    Jansson, Anette
    et al.
    Chalmers University of Technology, Sweden.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Löfgren, Ingemar
    Chalmers University of Technology, Sweden.
    Lundgren, Karin
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Gylltoft, Kent
    Thomas Concrete Group AB, Sweden.
    Experimental investigation of surface crack initiation, propagation and tension stiffening in self-compacting steel–fibre-reinforced concrete2012Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 45, nr 8, s. 1127-1143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To investigate crack initiation and propagation in reinforced, self-compacting, steel–fibre-reinforced concrete (SCSFRC) members, tie elements were tested in tension. Strain and surface crack formation were monitored with an optical strain measurement system based on digital image correlation. In addition, to capture the softening behaviour (s–w) of the material, uni-axial tension testing was performed on SCSFRC cylinders. The results show that, with the optical strain measurement system, it was possible to detect different cracking modes and to follow the crack growth. It was especially of interest to recognize that high fibre amounts tend to change a sudden opening of a crack (as in non-fibrous concrete) into a more stable procedure. It was found that, for a given crack width, the SCSFRC specimens exhibited a noticeably higher tension stiffening than the specimens without fibres. Moreover, at a given load, the crack widths decreased by as much as 65% for the SCSFRC specimens with a nominal fibre content of 1%. For the uni-axial tension tests the results showed that with higher fibre content, for this type of fibre and concrete, both the peak stress and the residual tensile stress were increased. Additionally, it was noted for both specimen types that the scatter in fibre distribution decreased with increasing fibre content.

  • 64.
    Jansson, Robert
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research, Brandmotstånd.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Albrektsson, Joakim
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research, Brandmotstånd.
    Lindqvist, Jan-Erik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Brandteknik, material (BRm).
    Optisk mätmetod visar hur långt in betongen skadats2011Inngår i: Husbyggaren, ISSN 0018-7968, Vol. 53, nr 2, s. 4 to 6-Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 65.
    Larsson, Jörgen
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik. KTH Royal Institute of Technology, Sweden.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    An Approach to Compensate for the Influence of the System Normal Stiffness in CNS Direct Shear Tests2020Inngår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 53, s. 2185-2199Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Applying accurate normal load to a specimen in direct shear tests under constant normal stiffness (CNS) is of importance for the quality of the resulting data, which in turn influences the conclusions. However, deficiencies in the test system give rise to a normal stiffness, here designated as system normal stiffness, which results in deviations between the intended and actual applied normal loads. Aiming to reduce these deviations, this paper presents the effective normal stiffness approach applicable to closed-loop control systems. Validation through direct shear tests indicates a clear influence of the system normal stiffness on the applied normal load (13% for the test system used in this work). The ability of the approach to compensate for this influence is confirmed herein. Moreover, it is demonstrated that the differences between the measured and the nominal normal displacements are established by the normal load increment divided by the system normal stiffness. This further demonstrates the existence of the system normal stiffness. To employ the effective normal stiffness approach, the intended normal stiffness (user defined) and the system normal stiffness must be known. The latter is determined from a calibration curve based on normal loading tests using a stiff test dummy. Finally, a procedure is presented to estimate errors originating from the application of an approximate representation of the system normal stiffness. The approach is shown to effectively reduce the deviations between intended normal loads and the actual applied normal loads.

    Fulltekst (pdf)
    fulltext
  • 66.
    Larsson, Jörgen
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Williams Portal, Natalie
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Johnson, Erland
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Johansson, F
    KTH Royal Institute of Technology, Sweden.
    Mas Ivars, D
    KTH Royal Institute of Technology, Sweden; SKB Swedish Nuclear Fuel and Waste Management Co, Sweden.
    Geometrical Quality Assurance of Rock Joint Replicas in Shear Tests – Introductory Analysis2020Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The presence of joints in rock masses influences the structural integrity of geotechnical structures. A critical failure mode is shearing, thus making the shearing process of importance to understand. Historically, studies have been mainly executed on the basis of laboratory experiments, since full-scale in situ tests are seldom performed due to technical and economic considerations. Since each rock joint is unique by nature, the utilization of replicas is applied to carry out controlled experimental parameter studies. However, the manufacturing process of replicas introduces many sources of uncertainty. Therefore, in this work the influence of geometrical variations in replicas on the shear strength characteristics is evaluated, mutually as well as in relation to the mother rock specimen of the replicas. The joint surfaces were 3D scanned and the contact area of the joint was measured using pressure sensitive film before direct shear tests. Deviations in morphology were evaluated by surface comparisons between the joint surfaces of the mother rock and replicas. The initial matching of the joints was evaluated by calibrating the scanning data with respect to the contact area measurements. It could be visualized that geometrical deviations were caused by rock fragments coming off during mould production, positioning of the moulds and pores resulting from replica casting. These factors were found to influence the shear strength characteristics of the replicas. The influence of the deviations originating from morphology on the joint matching is demonstrated. In summary, it is shown that replicas with similar shear strength characteristics as rock can be manufactured, but even small deviations affect the characteristics, in particular the peak strength. Therefore, parameters relevant for geometrical quality assurance should be identified along with required value ranges. Selected introductory results on quantified parameters for geometrical quality assurance are presented, serving as a basis for continued work.

  • 67.
    Larsson, Jörgen
    et al.
    KTH Royal Institute of Technology, Sweden.
    Johansson, F
    KTH Royal Institute of Technology, Sweden.
    Ivars, D. Mas
    KTH Royal Institute of Technology, Sweden; SKB Swedish Nuclear Fuel and Waste Management Co, Sweden.
    Johnson, Erland
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Williams Portal, Natalie
    RISE Research Institutes of Sweden, Material och produktion, Korrosion.
    A novel method for geometric quality assurance of rock joint replicas in direct shear testing : Part 2: Validation and mechanical replicability2023Inngår i: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755, Vol. 15, s. 2209-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Each rock joint is unique by nature which means that utilization of replicas in direct shear tests is required in experimental parameter studies. However, a method to acquire knowledge about the ability of the replicas to imitate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking. In this study, a novel method is presented for geometric quality assurance of replicas. The aim is to facilitate generation of high-quality direct shear testing data as a prerequisite for reliable subsequent analyses of the results. In Part 1 of this study, two quality assurance parameters, σmf and VHp100, are derived and their usefulness for evaluation of geometric deviations, i.e. geometric reproducibility, is shown. In Part 2, the parameters are validated by showing a correlation between the parameters and the shear mechanical behavior, which qualifies the parameters for usage in the quality assurance method. Unique results from direct shear tests presenting comparisons between replicas and the rock joint show that replicas fulfilling proposed threshold values of σmf < 0.06 mm and < 0.2 mm have a narrow dispersion and imitate the shear mechanical behavior of the rock joint in all aspects apart from having a slightly lower peak shear strength. The wear in these replicas, which have similar morphology as the rock joint, is in the same areas as in the rock joint. The wear is slightly larger in the rock joint and therefore the discrepancy in peak shear strength derives from differences in material properties, possibly from differences in toughness. It is shown by application of the suggested method that the quality assured replicas manufactured following the process employed in this study phenomenologically capture the shear strength characteristics, which makes them useful in parameter studies.

  • 68.
    Larsson, Jörgen
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik. KTH Royal Institute of Technology, Sweden.
    Johansson, F.
    KTH Royal Institute of Technology, Sweden.
    Ivars, DM
    KTH Royal Institute of Technology, Sweden; SKB Swedish Nuclear Fuel and Waste Management Co, Sweden.
    Johnson, Erland
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Williams Portal, Natalie
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    A novel method for geometric quality assurance of rock joint replicas in direct shear testing – Part 1: Derivation of quality assurance parameters and geometric reproducibility2023Inngår i: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755, Vol. 15, nr 9, s. 2193-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Since each rock joint is unique by nature, the utilization of replicas in direct shear testing is required to carry out experimental parameter studies. However, information about the ability of the replicas to simulate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking. With the aim to facilitate generation of high-quality direct shear test data from replicas, a novel component in the testing procedure is introduced by presenting two parameters for geometric quality assurance. The parameters are derived from surface comparisons of three-dimensional (3D) scanning data of the rock joint and its replicas. The first parameter, σmf, captures morphological deviations between the replica and the rock joint surfaces. σmf is derived as the standard deviation of the deviations between the coordinate points of the replica and the rock joint. Four sources of errors introduced in the replica manufacturing process employed in this study could be identified. These errors could be minimized, yielding replicas with σmf ≤ 0.06 mm. The second parameter is a vector, VHp100, which describes deviations with respect to the shear direction. It is the projection of the 100 mm long normal vector of the best-fit plane of the replica joint surface to the corresponding plane of the rock joint. |VHp100| was found to be less than or equal to 0.36 mm in this study. Application of these two geometric quality assurance parameters demonstrates that it is possible to manufacture replicas with high geometric similarity to the rock joint. In a subsequent paper (part 2), σmf and VHp100 are incorporated in a novel quality assurance method, in which the parameters shall be evaluated prior to direct shear testing. Replicas having parameter values below established thresholds shall have a known and narrow dispersion and imitate the shear mechanical behavior of the rock joint.

  • 69.
    Larsson, Jörgen
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik. KTH Royal Institute of Technology, Sweden.
    Johansson, F
    Mas Ivars, D
    Johnson, Erland
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Williams Portal, Natalie
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Rock joint replicas in direct shear testing – Part 1: Extraction of geometrical quality assurance parameters.Manuskript (preprint) (Annet vitenskapelig)
  • 70.
    Lindqvist, Jan Erik
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Flansbjer, Mathias
    Flerskalig metodik för att undersöka betongs mekaniska respons2012Inngår i: CBI-nytt, ISSN 0349-2060, nr 1, s. 4-5Artikkel i tidsskrift (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 71.
    Lindqvist, Jan Erik
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB, Tillståndsbedömningar.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Hansson, Erik
    Inspecta.
    Analysis of irradiated concrete: Microscopic and mechanical tests on concrete from a nuclear power plant containment structure2016Rapport (Annet vitenskapelig)
    Abstract [en]

    Drilled concrete cores from the centralpart of the containment structure of reactor 2 in Oskarshamn weretested in the present study. Optical microscopy and scanning electron microscopy wereapplied.The microscopy analyses performed have not documented any changes in the properties of the concrete that can be interpreted as beingdue to the specific environment to which the samples havebeen exposed. The parameters that havebeen studied includecrack patterns that could indicate volume changes inthe aggregate or cement pasteand indications of alkali silica reaction. The observed differences in the concrete surface compared to the inner part of the concrete are such that they couldoccur in concrete exposed to a normal indoor environment. There are no crack patterns to indicatethat the radiation has caused a volume increase inthe aggregate or drying shrinkage in the cement paste. Thereareno changesin the crack patterns, porosity or polarization properties that may indicate reduced mechanical strength. The damage seen in the surface of sample 5 is likely to have beencaused by a local mechanical impact and thisdamage is superficial andlocal. The mechanical properties of the concrete were evaluated by uniaxial compression tests on cylinders machined from drilled cores. Full-field strain measurement was performed on the surface of the cylinders during the compression test. Optical full-field deformation measurement was conducted usinga measurement technique based on Digital Image Correlation (DIC) with a stereoscopic camera set-up, consisting of two CCDcameras. The basic idea behind DIC is to measure the deformation of the specimen duringtesting by tracking the deformation of a surface speckle pattern in a series of digital images acquired during loading. That there is some variation in strain between the various segments is natural, since the local stiffness depends on aggregate sizeand location. The general picture is that the strain distribution is relatively uniform along the length of the cylinder,which indicates that the tested cylinders do not exhibit any degradation of mechanical properties. There is also no significant difference between the cylinders taken towards the insideof the structure, compared with thosetaken towards the outside.The overall conclusion is that the tests carried out do not indicate any degradation of the mechanical properties, and that the properties in general are equivalent for the cores taken towards the inside and the outside of the structure.

  • 72.
    Lindström, Camilla
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Safety.
    Appelquist, Karin
    Ramboll, Sweden.
    Brander, Linus
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Sjöqvist, Lovise
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Kvantifiering av mikrostrukturer och dess inverkan på sprickbildning i berg2019Rapport (Annet vitenskapelig)
    Abstract [en]

    A new methodology based on monitoring of crack propagation during small-scale mechanical tests on sawn rock prisms under tension has been developed. The methodology includes a combination of different experimental methods and measuring techniques at different scale levels. Material testing is performed through a tensile stage. Crack monitoring is performed by means of Digital Image Correlation and Acoustic Emission. After the test, microcrack and fracture patterns are studied and quantified in thin-sections using fluorescent light under a petrographic microscope.

    By using Digital Image Correlation it is possible to follow crack propagation in relation to the microstructure on the surface of the specimen in a detailed way, whereas Acoustic Emission offers real-time measurement of the crack activity within the specimen. By combining these techniques, it is possible to relate the Acoustic Emission signal characteristics to different phases of the cracking process, such as crack initiation, propagation and bridging of microcracks into macrocracks as well as the creation and localization of the final fracture. After the tensile stage test, crack patterns and the final fractures are studied in detail using polarizing and fluorescence microscopy, establishing the relationship of these. The methodology is practiced to increase the knowledge of critical parameters affecting cracking processes in rock materials and to show how this is related to the material's microstructure as well as mesostructure.

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  • 73.
    Malaga, Katarina
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Tammo, Kristian
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Williams Portal, Natalie
    REr.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Alkali Resistance of Textile Reinforcement for Concrete Façade Panels2014Inngår i: XXII NORDIC CONCRETE RESEARCH SYMPOSIUM, 2014, , s. 61-64, Publication no. 50Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Textile reinforced concrete has been proven to be a suitable solution for the production of thin and lightweight façade panels. Despite it being researched over the past decade, its long-term durability is not sufficiently characterized. This article presents experimental results from accelerated aging and direct tensile testing of various textile reinforcement alternatives according to ISO 10406-1. Based on the results, a large degeneration of the glass and basalt fibre bars was observed after 30 days of immersion. As for carbon fibre grids, no significant difference in ultimate tensile force was noted before and after immersion.

  • 74.
    Mathern, Alexandre
    et al.
    Chalmers University of Technology, Sweden; NCC Infrastructure, Sweden.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety. Chalmers University of Technology, Sweden.
    Löfgren, Ingemar
    Thomas Concrete Group, Sweden; Chalmers University of Technology, Sweden.
    Magnusson, Jonas
    NCC Infrastructure, Sweden.
    EXPERIMENTAL STUDY OF TIME-DEPENDENTPROPERTIES OF A LOW-PH CONCRETE FOR DEPOSITIONTUNNELS2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Swedish Nuclear Fuel and Waste Management Company developed a method for the final disposal of canisters for spent nuclear fuel in tunnels at depths of about 500 meters. The concept for closure of the deposition tunnels is based on a bentonite seal supported by a spherical concrete dome structure. In order to fulfil the requirements specific to the repository concept, a special mix of lowpH self-compacting concrete was developed. A series of large-scale castings and laboratory tests were conducted to gain experience on this low-pH concrete mix, in conjunction with the full-scale demonstration test of an unreinforced concrete dome plug in the underground hard rock laboratory in Äspö, Sweden. The laboratory tests aimed at studying the creep properties under high sustained compressive stresses of the low-pH concrete mix, its shrinkage properties and the properties of the rock-concrete interface. This paper provides an overview of these tests and analyses the latest results of the recently completed creep tests, which include 6 years of measurements. These results allow to improve understanding of the structural behaviour of the concrete plug and to assess the effects of the very high pressure acting on the plug on its deformations, cracking and water tightness.

  • 75.
    Mueller, Urs
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Williams Portal, Natalie
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Chozas, Valle
    ACCIONA, Spain.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Larraza, Inigo
    ACCIONA, Spain.
    da Silva, Nelson
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Malaga, Katarina
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Reactive powder concrete for facade elements: A sustainable approach2016Inngår i: Journal of Facade Design and Engineering, ISSN 2213-302X, Vol. 4, nr 1-2, s. 53-66Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reactive powder concrete (RPC) is a fairly novel material with extraordinary strength and durability properties. Due to these properties, it is increasingly being utilized for external fa¸cade cladding thus enabling a considerable reduction in the thickness of concrete elements. Commercial RPC formulations on the market are usually expensive and less sustainable due to high cement clinker contents. In this study, improved RPC formulations with higher amounts of supplementary cementitious materials (SCMs) were developed. The formulations were combined with different types of reinforcements ranging from steel fibres to fibre textile grids primarily to enhance the ductility and tensile strength of the composite material. The results showed that even with clinker replacement levels of up to ca. 40% of the total binder amount, a satisfactory mechanical performance of the RPC mixes could still be achieved. A fairly steep strength gain rendered heat treatment unnecessary. The materials displayed good flow properties and a reasonably short initial setting time. The incorporation of carbon textile fibre grids proved to be highly effective in improving the post cracking behaviour of the RPC. The results validated a more sustainable approach for RPC applied to thin fa¸cade elements. 

  • 76.
    Mueller, Urs
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Williams Portal, Natalie
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Textile Reinforced Reactive Powder Concrete and its Application for Facades2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Reactive powder concrete (RPC) is a fairly novel material with extraordinary strength and durability properties. Due to these properties, it is increasingly being utilized also for external facade cladding thus enabling a considerable reduction in the thickness of concrete elements. Commercial RPC formulations on the market have drawbacks in terms of sustainability due to their high clinker content and heat curing which is often applied to increase final strength and material density. The presented study focusses on improved formulations with higher replacement levels of cement clinker by supplementary cementitious materials (SCMs). One different mix formulation was designed and tested in terms of mechanical properties. The formulation was combined with carbon textile reinforcements primarily to enhance the flexural and tensile behavior of the material. The results showed that even with clinker replacement levels of up to 33 % of the total binder amount, a satisfactory mechanical performance of the RPC mix could still be achieved. Fairly steep strength gains rendered heat treatment unnecessary. The incorporation of carbon textile fiber grids proved to be effective in improving the post peak performance of the RPC. However, their performance depended strongly on the bond between the carbon grid and the RPC. Higher moister contents in the concrete proved to reduce the bond strength between the carbon textile and the cement paste. This is maybe less relevant for facades but structural elements with textile reinforcement and RPC might perform less well in completely submerged environment.

  • 77.
    Robuschi, S.
    et al.
    Chalmers University of Technology, Sweden.
    Lundgren, K.
    Chalmers University of Technology, Sweden.
    Fernandez, I.
    Chalmers University of Technology, Sweden.
    Zandi, K.
    Chalmers University of Technology, Sweden.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety. Chalmers University of Technology, Sweden.
    Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures2018Inngår i: Proceedings of the 12th fib International PhD Symposium in Civil Engineering, Czech Technical University , 2018, s. 1039-1046Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Concrete structures are strongly affected by reinforcement corrosion, the most common cause of deterioration. Most studies on structural effects of corrosion rely on artificial methods to obtain a corrosion level that would otherwise require years, but doubts on the soundness of the methods have been raised. Specimens taken from existing structures offer the chance of studying the effect of natural corrosion, however the choice of the test setup is challenging. Hence, pilot tests are carried out to investigate the optimal design for testing the anchorage capacity of specimens with smooth reinforcements. The outcome is an asymmetrically supported 3-point bending beam test. The benefits of using complementary tools as Digital Image Correlation (DIC), Non-Linear Finite Element Analysis (NLFEA), pull-out tests and tensile tests and 3D scanning of the bars are presented.

  • 78.
    Robuschi, Samanta
    et al.
    Chalmers University of Technology, Sweden.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    Fernandez, Ignasi
    Chalmers University of Technology, Sweden.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik. Chalmers University of Technology, Sweden.
    Anchorage of naturally corroded, plain reinforcement bars in flexural members2020Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 53, nr 2, artikkel-id 38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reinforced concrete structures are often damaged by corrosion, which affects the interaction between reinforcement bars and concrete. Earlier studies mostly applied artificial corrosion to test the bond between deformed bars and concrete. However, there is a lack of knowledge on the effects of natural corrosion on plain bars. In this paper, 20 beams with naturally corroded plain bars and varying amount of damage were taken from an 80-year-old bridge and tested in three-point bending. All but three of the specimens anchored the yield force of the bars after the opening of one or two major bending cracks. At large deflections, the load-carrying mechanism changed from beam to arch action. Eventually, end-slip of the reinforcement bars was observed. The bars were extracted, cleaned, three-dimensionally scanned, and tested in tension. The average bond strength in the unyielded zone was found to be equal to 7.39 MPa, with a standard deviation of 3.33 MPa. The casting position was identified as an important factor: when uncorroded, bottom-cast bars had a higher bond strength than that of top-cast bars. However, they were more prone to splitting cracks and, consequently, loss of bond strength for small corrosion levels. Top-cast bars had increasing bond strength with increasing corrosion levels, owing to the absence of external cracks. These differences were likely related to a denser concrete surrounding the bottom-cast bars. The remaining bond capacity in the yielded zones was evaluated to be approximately 1.0 MPa. © 2020 The Author(s).

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  • 79. Seiffedine, S
    et al.
    Sjögren, Torsten
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Inverkan av porer på mekaniska egenskaper i gjutna aluminiumkomponenter2009Inngår i: Gjuteriet, Vol. 5, nr 8, s. 21-23Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 80.
    Suchorzewski, Jan
    et al.
    RISE Research Institutes of Sweden, Samhällsbyggnad, Infrastruktur och betongbyggande.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Arun Chaudhari, Ojas
    RISE Research Institutes of Sweden, Samhällsbyggnad, Infrastruktur och betongbyggande.
    Williams Portal, Natalie
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Experimental Development and Field Validation of Rock Anchors for Sustainable Onshore Foundations2024Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 2745, artikkel-id 012011Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of an innovative rock anchor prototype manufactured using high strength steel sheets produced locally in Sweden is the core of the PROWIND concept. Steel sheets provide a design freedom to easily manufacture complex geometries, which can be advantageous to enhance the shear force transmission in the bond-length segment of the anchor. The underlying challenge of this concept has been to design a solution which meets the design requirements of today and future technological advancements, all while keeping conventional installation practices in mind. The project followed a 4-step development process: (1) concept analysis and modelling, (2) small-scale prototypes testing and (3) large scale lab-validation and lastly (4) field validation. The performance of the developed rock anchor prototype and grouting material was experimentally quantified on both small and large-scale test specimens and also validated in full scale in the field concerning installation process, proof-loading and maintaining the prestress over time. The PROWIND anchors with the end feature with ribbed design have 4-5 times higher load bearing capacity. The experience from the anchor installation proved that the developed grout and anchors are faster and easier to install. The field test in two different geological conditions has proven that the news design is reducing the required anchorage length to just 1 meter. The restressing of anchors is fully possible with the proposed lock-off solution with a nut. All of those contribute to lower costs of installations and possibly longer service-life.

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  • 81. Williams Portal, Natalie
    et al.
    Flansbjer, Mathias
    Alkali resistance of textile reinforcement for concrete facade panels2014Inngår i: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, nr 2, s. 61-64Artikkel i tidsskrift (Fagfellevurdert)
  • 82.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Assessment of Fire Exposed Concrete with Full-field Strain Determination and Predictive Modelling2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A condition assessment of civil engineering structures is typically performed after the occurrence of a fire incident to determine the remedial actions required out of a structural point of view. A condition assessment is based on the mapping of damage on the given structure, which is traditionally executed via methods that yield indirect results related to surface and/or geometric properties. To be able to predict the accurate fire resistance performance of a given structure, it is most suitable to apply a mapping method which can be directly coupled to the change in material properties of concrete at high temperatures. The aim of this study is to explore the potential of applying an innovative damage mapping methodology directly coupled to the change in material properties of concrete at high temperatures. This methodology consists of optical full-field strain measurements based on Digital Image Correlation (DIC) coupled with a predictive model based on finite-element analysis (FEA). An experimental study was firstly conducted to expose concrete slabs to a standard fire curve. Subsequently, compression tests were performed on drilled cores taken from the damaged induced specimens, all while optically measuring the full-field strain on a specimen surface. As a preliminary step, an FE model of a fire exposed core was developed based on input data from standard temperature-dependent properties. The analysis consisted of a sequentially coupled thermal stress analysis to solve the multiphysics problem. The model was able to capture the temperature distribution in the concrete with enough certainty given the choice of input data. The resulting strain along the height of the core was also comparable to the experimental optical strain measurements, particularly as the distance increased from the fire exposed surface. These results can be practical when assessing the required strengthening actions to restore the load carrying capacity and durability of the concrete structure.

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  • 83.
    Williams Portal, Natalie
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Bäckstrand, Albin
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    HCT-City - Bromätning i Varberg2023Rapport (Annet vitenskapelig)
    Abstract [sv]

    Projektet HCT City studerar hur HCT-konceptet (High Capacity Transport) kan appliceras i städer, genom piloter i Varberg och Stockholm samt analyser i Sundbyberg och Uppsala. I projektet testas hypotesen att HCT-konceptet kan förbättra både produktiviteten och transporteffektiviteten avsevärt och därmed minska utsläppen av CO2 och hälsovådliga emissioner, samtidigt som effekter avseende vägslitage och trafiksäkerhet minskas eller förblir oförändrade. Inom ramen för projektet har effekter adresserats vid utbyte av konventionella tunga fordon och kontroll mot HCT-fordon beträffande: trafiksäkerhet och påverkan/nedbrytning av gator, broar och vägar i tätorten. Denna rapport omfattar en fallstudie där kontrollerad fältmätning genomfördes på en utvald bro belägen på Österleden i Varberg. Mer specifikt utfördes deformationsmätning för att förstå konstruktionen verkningssätt beroende på bland annat fordonsvikt- och hastighet. De utförda mätningarna visar att brofarbanans nedböjning är generellt relativt liten och påkänningarna följaktligen är små vid passage av referensfordon och andra fordon under den aktuella mätperioden. Referensfordonets hastighet avspeglar sig i varaktigheten för brofarbanans nedböjning. Hastighet vid bropassagen verkar dock inte ha någon större inverkan på brofarbanans respons, vilket tyder på att den dynamiska effekten är liten för den aktuella bron.

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  • 84.
    Williams Portal, Natalie
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Carró‐Lopez, Diego
    Universidade da Coruña, Spain.
    Fernandez, Ignasi
    Chalmers University of Technology, Sweden.
    Analysis of tensile behavior of recycled aggregate concrete using acoustic emission technique2020Inngår i: RILEM Technical Letters, ISSN 2518-0231, Vol. 5, s. 131-140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recycled concrete aggregate (RCA) was processed from reinforced concrete edge beams sourced from a demolished bridge in Sweden. This material replaced different ratios of coarse aggregate in a benchmark concrete. The tensile behavior of the developed concrete mixes was characterized via monotonic and cyclic uniaxial tensile tests performed on notched cylinders. Such tensile tests allow for the quantification of the fracture energy and softening behavior of the concrete. Moreover, acoustic emission (AE) measurements were conducted in conjunction with the cyclic tests to characterize e.g. micro‐crack initiation and development, as well as crack localization. The tensile behavior of the various materials was found to be similar with minimal variation in the results. However, the softening behavior suggests that the RCA materials are slightly more brittle compared to both the mother and benchmark materials, which could be indicative of differences in the interface transition zones. The corresponding AE measurements also indicated similarities between the micro‐crack initiation and development for these mixes. It can be constituted that if the concrete used to produce RCA is of high quality and from one source, the resulting RAC will have adequate tensile properties with minimal variation, despite the aggregate replacement ratio. © The Author(s) 2020.

  • 85.
    Williams Portal, Natalie
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.
    Flansbjer, MathiasRISE Research Institutes of Sweden, Material och produktion, Tillämpad mekanik.Carró-Lopez, DiegoFernandez, Ignasi
    Analysis of tensile behavior of recycled aggregate concrete using acoustic emission technique2020Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    Recycled concrete aggregate (RCA) was processed from reinforced concrete edge beams sourced from a demolished bridge. This material replaced different ratios of coarse aggregate in a benchmark concrete. The tensile behavior of the developed concrete mixes was characterized via monotonic and cyclic uni-axial tensile tests performed on notched cylinders. Such tensile tests allow for the quantification of the fracture energy and softening behavior of the concrete. Moreover, acoustic emission (AE) measurements were conducted in conjunction with the cyclic tests to characterize e.g. micro-crack initiation and development, as well as crack localization. The tensile behavior of the various materials was found to be similar with minimal variation in the results. However, the softening behavior suggests that the RCA materials are slightly more brittle compared to both the mother and benchmark materials. The corresponding AE measurements also indicated similarities between the micro-crack initiation and development for these mixes. It can be constituted that if the concrete used to produce RCA is of high quality and from one source, the resulting RAC will have adequate tensile properties with minimal variation, despite the aggregate replacement ratio.

  • 86.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Honfi, Daniel
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Byggteknik.
    Testing of self-supporting laminated glass balustrades2019Rapport (Annet vitenskapelig)
    Abstract [en]

    The work carried out within Task 2 Experimental work of the ÅForsk funded project "Structural safety of glass components" is presented in this report. The main goal of this project was to improve the understanding about the structural safety of self-supporting glass components. In particular, the results of the project intended to extend the current knowledge about the effect of impact and related testing methods regarding the safety of glass structures.

    Static and impact tests were conducted on a self-supporting glass balustrade with point-fixings. The laminated glass consisted of two 10 mm thick layers of laminated glass and a 0.76 mm thick interlayer made of EVA (ethylene vinyl acetate). A static line load was cyclically applied to the top of the specimen to gain an understanding of the static behaviour of the glass structure and to minimize the settlement in the structure prior to applying impact loading. The specimen was subsequently subjected to dynamic loading by impact tests based on EN 12600 (pendulum impact) with different drop heights until attaining failure. The dynamic structural response of the glass balustrade was analysed by three-dimensional Digital Image Correlation (3D-DIC). This measurement technique made it possible to directly relate the measurement of any point to the specimen and to study the deformed 3D shape in detail during the impact test. The FE-analysis (FEA) conducted using SJ Mepla was found to correlate rather well with the dynamic test results particularly up to the initial peak displacement.

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  • 87.
    Williams Portal, Natalie
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB, Betong & Berg. Chalmers University of Technology, Sweden.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut. Chalmers University of Technology, Sweden.
    Johannesson, Pär
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Malaga, Katarina
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    Tensile behaviour of textile reinforcement under accelerated ageing conditions2016Inngår i: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 5, s. 57-66Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Textile reinforced concrete (TRC) has emerged as a promising alternative wherein corrosion is no longer an issue and much thinner and light-weight elements can be designed. Although TRC has been expansively researched, the formalization of experimental methods concerning durability arises when attempting to implement and design such innovative building materials. In this study, accelerated ageing tests paired with tensile tests were performed. The change in physico-mechanical properties of various commercially available textile reinforcements was documented and evaluated. The ability for the reinforcements to retain their tensile capacity was also quantified in the form of empirical degradation curves. It was observed that accelerated test parameters typically applied to fibre-reinforced polymer (FRP) bars and grids are generally too aggressive for the textile reinforcement products and alternative boundary conditions are necessary. The developed degradation curves were found to have an overall good correlation with the experimental findings.

  • 88. Williams Portal, Natalie
    et al.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Lundgren, Karin
    Malaga, Katarina
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Implementation of experimental data in analyses of textile reinforced concrete structures2015Inngår i: FERRO-11 – 11th International Symposium on Ferrocement and 3rd ICTRC - International Conference on Textile Reinforced Concrete, 2015, , s. 149-158Konferansepaper (Annet vitenskapelig)
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  • 89.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Anchorage of Textile Reinforcement in High-Performance Concrete2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The mechanical properties of textile reinforced high-performance concrete (TRHPC) applied in innovative lightweight sandwich elements has been investigated in the framework of EC supported FP7 project, H-House (Healthier Life with Eco-innovative Components for Housing Constructions). TRHPC offers new possibilities for architects and engineers to create thinner and more durable concrete façade elements. Textile reinforcement grids are typically woven from non-metallic rovings usually consisting of continuous glass, rock or carbon fibres. The most promising performing textile reinforcement alternative in terms of mechanical and durability performance consists of carbon fibres. Carbon fibres do however have an inherent smooth surface which is unfavourable concerning its bond to the cement paste, which is often improved by polymer-based coatings. The bond behaviour, being a critical design parameter, should be investigated for TRHPC in order to understand limitations regarding required anchorage lengths for use in applications such as façade elements. The aim of this study was to quantify and verify the required anchorage length for a selected epoxy impregnated carbon textile reinforced TRHPC combination. To achieve this aim, the bond behaviour, leading to a suitable anchorage length (or overlap), was firstly studied by means of pull-out tests. Thereafter, the ultimate strength of the composite material was measured via uniaxial tensile testing with and without an overlap splice according to the findings from the pull-out tests. Optical measurements during the pull-out tests were performed using a video extensometer technique and by Digital Image Correlation (DIC) for the uniaxial tensile tests. Results indicated that the required anchorage length to yield rupture of the textile reinforcement in pull-out was deemed appropriate as an overlapping length when tested in tension. The combination of these two experimental methods on the composite level was useful for determining the overlapping length required for the TRHPC which could be applied in larger scale applications.

  • 90.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, MathiasRISE - Research Institutes of Sweden, Säkerhet och transport, Safety.Mueller, UrsRISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Analysis of the Flexural Behavior of Textile Reinforced Reactive Powder Concrete Sandwich Elements Using Optical Measurements2018Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    Prefabricated and non-load bearing sandwich façade elements were developed using Textile Reinforced Reactive Powder Concrete (TRRPC) along with low density Foamed Concrete (FC) and Glass Fiber Reinforced Polymer (GFRP) continuous connecting devices. Four-point bending tests were performed on large-scale TRRPC sandwich element beams to characterize the structural performance, which included the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on Digital Image Correlation (DIC) were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behavior of the developed elements was found to be highly dependent on the stiffness and strength of the connectors to ensure composite action between the two TRRPC panels.

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  • 91.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Safety.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Samhällsbyggnad, CBI Betonginstitutet.
    Experimental Study on Anchorage in Textile Reinforced Reactive Powder Concrete2017Inngår i: Nordic Concrete Research, ISSN 0800-6377, Vol. 57, nr 2, s. 73-88, artikkel-id 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The EC funded project SESBE (Smart Elements for Sustainable Building Envelopes) focused on utilizing new types of cementitious materials for reducing the mass and thickness of façade elements while increasing their thermal performance. A method enabling the quantification and verification of the required anchorage length for a given textile reinforced reactive powder concrete (TRRPC) is presented. At the material level, tensile tests were conducted to determine the tensile properties of the reinforcement. Pull-out tests were applied to quantify the required anchorage length, while uniaxial tensile tests were performed to quantify the ultimate strength and verify the suitability of the anchorage length at the composite level. The combination of these methods was deemed useful to determine the overlapping length required for larger scale façade applications.

  • 92.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Safety.
    Zandi, Kamyab
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Wlasak, Lech
    Mostostal Warszawa SA, Poland.
    Malaga, Katarina
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, CBI Betonginstitutet.
    Bending behaviour of novel Textile Reinforced Concrete-foamed concrete (TRC-FC) sandwich elements2017Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 177, s. 104-118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel sandwich element design consisting of two facings made of carbon reinforced Textile Reinforced Concrete (TRC), a low density foamed concrete (FC) core and glass fibre reinforced polymer (GFRP) connecting devices was experimentally investigated according to quasi-static and cyclic quasi-static fourpoint bending. Optical measurements based on Digital Image Correlation (DIC) were taken during testing to enable a detailed analysis of the bending behaviour and level of composite action. A model, verified by the experiments, was developed based on non-linear finite element analysis (NLFEA) to gain further insight on the failure mechanisms. Under both loading conditions, the bending behaviour of the TRCFC composite elements was characterized by favourable load bearing capacity, partial composite action, superior ductility and multiple fine cracking. The connecting devices were found to be the critical elements causing the initial failure mechanism in the form of localized pull-out within an element.

  • 93.
    Williams Portal, Natalie
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Godio, Michele
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Flansbjer, Mathias
    RISE Research Institutes of Sweden, Material och produktion, Kemi och Tillämpad mekanik.
    Byggnevi, Magnus
    Swedish Fortification Agency, Sweden.
    Magnusson, Johan
    Swedish Fortification Agency, Sweden.
    Quasi-static out-of-plane testing of unreinforced masonry walls instrumented with optical measurements2021Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Masonry buildings have existed in Sweden since the Middle Ages. The use of brick masonry as a construction material was pivotal until the beginning of the 20th century. Unreinforced masonry walls (URM) are massive and act as a protective system, yet they have limited capacity against explosions. When exposed to blasts, they experience out-of-plane failure, which engenders flying debris inside the building and may affect the stability of the building. Knowledge pertaining to the design and strengthening of URM walls against blasts has been identified as insufficient, on a Swedish context, to answer the current threats. In this paper, the results from quasi-static out-ofplane tests performed on URM walls made of clay bricks and lime-based mortar are presented. The tests were performed at RISE Research Institutes of Sweden by applying an incremental outof-plane displacement, while applying an axial load at the wall’s top edge. RC slabs were affixed over and below the walls to simulate the contact condition of a typical system. Two different types of support were tested for the upper slab: a) where the slab could slide along the vertical direction, and b) where this was prevented, leading to an arching action inside the wall. The results were generated as a part of an initial experimental stage of a project investigating URM walls loaded laterally by static and blast loads with optical measurements. Ultimately, the results will be used to verify existing models and/or develop a new model for the load-deformation relationship.

  • 94.
    Zandi Hanjari, Kamyab
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Flansbjer, Mathias
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Hållfasthet (BMh).
    Lindqvist, Jan-Erik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Brandteknik, material (BRm).
    Silfwerbrand, Johan
    RISE., SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Structural analysis of concrete members with shear failure2012Inngår i: fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings, 2012, , s. 165-168s. 165-168Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper aims to improve the knowledge of the shear response in reinforced concrete and the influence of aggregate interlock using non-linear finite element analysis. The influence of aggregate types on shear response of concrete was studied with finite element analysis of reinforced concrete beams failed in shear. The influence of aggregate interlock was investigated using different smeared crack approaches, i.e. multi directional, fixed and rotating crack models. The results from analysis are verified with the result from mechanical testing with respect to stiffness, capacity and crack pattern.

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