Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 73) Show all publications
Lindström, C., Flansbjer, M., Appelquist, K., Brander, L. & Sjöqvist, L. (2019). Kvantifiering av mikrostrukturer och dess inverkan på sprickbildning i berg.
Open this publication in new window or tab >>Kvantifiering av mikrostrukturer och dess inverkan på sprickbildning i berg
Show others...
2019 (Swedish)Report (Other academic)
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.

Publisher
p. 84
Series
RISE Rapport ; 2019:37
Keywords
Acoustic Emission, digital image correlation, direct tensile test, polarization microscopy, fluorescent light petrography, rock mechanics, microcracks, fracture
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38314 (URN)978-91-88907-64-6 (ISBN)
Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2019-04-04
Flansbjer, M., Williams Portal, N. & Vennetti, D. (2019). Verification of the structural performance of textile reinforced reactive powder concrete sandwich facade elements. Applied Sciences, 9(12), Article ID 456.
Open this publication in new window or tab >>Verification of the structural performance of textile reinforced reactive powder concrete sandwich facade elements
2019 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 9, no 12, article id 456Article in journal (Refereed) Published
Abstract [en]

As a part of the SESBE (Smart Elements for Sustainable Building Envelopes) project, non-load bearing sandwich elements were developed with Textile Reinforced Reactive Powder Concrete (TRRPC) for outer and inner facings, Foam Concrete (FC) for the insulating core and Glass Fiber Reinforced Polymer (GFRP) continuous connectors. The structural performance of the developed elements was verified at various levels by means of a thorough experimental program coupled with numerical analysis. Experiments were conducted on individual materials (i.e., tensile and compressive tests), composites (i.e., uniaxial tensile, flexural and pull-out tests), as well as components (i.e., local anchorage failure, shear, flexural and wind loading tests). The experimentally yielded material properties were used as input for the developed models to verify the findings of various component tests and to allow for further material development. In this paper, the component tests related to local anchorage failure and wind loading are presented and coupled to a structural model of the sandwich element. The validated structural model provided a greater understanding of the physical mechanisms governing the element's structural behavior and its structural performance under various dead and wind load cases. Lastly, the performance of the sandwich elements, in terms of composite action, was shown to be greatly correlated to the properties of the GFRP connectors, such as stiffness and strength

Place, publisher, year, edition, pages
MDPI AG, 2019
Keywords
Finite element analysis (FEA), Foam concrete (FC), Reactive powder concrete (RPC), Sandwich elements, Textile reinforced concrete (TRC), Wind loading
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39376 (URN)10.3390/app9122456 (DOI)2-s2.0-85068191709 (Scopus ID)
Available from: 2019-07-08 Created: 2019-07-08 Last updated: 2019-07-08Bibliographically approved
Flansbjer, M., Williams Portal, N., Hall, S. & Engqvist, J. (2018). Analysis of Failure Modes in Fiber Reinforced Concrete Using X-rayTomography and Digital Volume Correlation. In: : . Paper presented at 18th International Conference on Experimental Mechanics, Brussels, Belgium, 1–5 July 2018..
Open this publication in new window or tab >>Analysis of Failure Modes in Fiber Reinforced Concrete Using X-rayTomography and Digital Volume Correlation
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Pull-out mechanisms for different common steel fibers were investigatedusing adapted pull-out tests performed in-situ in an x-ray micro tomograph(µXRT). High-resolution volume images from the µXRT scans enable clearvisualization of aggregates, pores, the fiber and the fiber-matrix interface.Furthermore, the natural density speckle pattern from aggregate distributionand pores was found suitable for Digital Volume Correlation (DVC) analysis.From the DVC results it was possible to visualize and quantify the straindistribution in the matrix around the fiber at the different load levels up tofinal failure, being marked by either pull-out or fiber rupture. This studydemonstrates that strain measurements within the concrete matrix can beobtained successfully using µXRT imaging and DVC analysis, which leads to anincreased understanding of the interaction mechanisms in fibre reinforcedconcrete under mechanical loading.

Keywords
Fiber reinforced concrete; pull-out behavior; X-ray Computed Tomography, Digital Volume Correlation
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:ri:diva-35557 (URN)
Conference
18th International Conference on Experimental Mechanics, Brussels, Belgium, 1–5 July 2018.
Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Williams Portal, N., Flansbjer, M. & Mueller, U. (Eds.). (2018). Analysis of the Flexural Behavior of Textile Reinforced Reactive Powder Concrete Sandwich Elements Using Optical Measurements. Paper presented at 18th International Conference on Experimental Mechanics, Brussels, Belgium, 1–5 July 2018.. MDPI
Open this publication in new window or tab >>Analysis of the Flexural Behavior of Textile Reinforced Reactive Powder Concrete Sandwich Elements Using Optical Measurements
2018 (English)Conference proceedings (editor) (Refereed)
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.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
Reactive Powder Concrete; Textile Reinforced Concrete; Foam Concrete; Glass Fiber
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-33930 (URN)10.3390/ICEM18-05221 (DOI)
Conference
18th International Conference on Experimental Mechanics, Brussels, Belgium, 1–5 July 2018.
Funder
EU, FP7, Seventh Framework Programme, 608950
Available from: 2018-06-11 Created: 2018-06-11 Last updated: 2018-08-16Bibliographically approved
Robuschi, S., Lundgren, K., Fernandez, I., Zandi, K. & Flansbjer, M. (2018). Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures. In: Proceedings of the 12th fib International PhD Symposium in Civil Engineering: . Paper presented at 12th fib International PhD Symposium in Civil Engineering, 29 August 2018 through 31 August 2018 (pp. 1039-1046).
Open this publication in new window or tab >>Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures
Show others...
2018 (English)In: Proceedings of the 12th fib International PhD Symposium in Civil Engineering, 2018, p. 1039-1046Conference paper, Published paper (Refereed)
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.

Keywords
Anchorages (foundations), Corrosive effects, Deterioration, Electrochemical corrosion, Tensile testing, Complementary tools, D. digital image correlation (DIC), Existing structure, Non-linear finite-element analysis, Reinforced structures, Reinforcement corrosion, Smooth reinforcement, Structural effect, Reinforcement
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35932 (URN)2-s2.0-85053855698 (Scopus ID)9788001064016 (ISBN)
Conference
12th fib International PhD Symposium in Civil Engineering, 29 August 2018 through 31 August 2018
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-06Bibliographically approved
Robuschi, S., Lundgren, K., Fernandez, I., Zandi, K. & Flansbjer, M. (2018). Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures. In: Proceedings of the 12th fib International PhD Symposium in Civil Engineering: . Paper presented at 12th fib International PhD Symposium in Civil Engineering, 29 August 2018 through 31 August 2018 (pp. 1039-1046). Czech Technical University
Open this publication in new window or tab >>Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures
Show others...
2018 (English)In: Proceedings of the 12th fib International PhD Symposium in Civil Engineering, Czech Technical University , 2018, p. 1039-1046Conference paper, Published paper (Refereed)
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.

Place, publisher, year, edition, pages
Czech Technical University, 2018
Keywords
Anchorages (foundations), Corrosive effects, Deterioration, Electrochemical corrosion, Tensile testing, Complementary tools, D. digital image correlation (DIC), Existing structure, Non-linear finite-element analysis, Reinforced structures, Reinforcement corrosion, Smooth reinforcement, Structural effect, Reinforcement
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-37264 (URN)2-s2.0-85053855698 (Scopus ID)9788001064016 (ISBN)
Conference
12th fib International PhD Symposium in Civil Engineering, 29 August 2018 through 31 August 2018
Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2019-01-21Bibliographically approved
Flansbjer, M., Williams Portal, N., Vennetti, D. & Mueller, U. (2018). Composite Behaviour of Textile Reinforced Reactive Powder Concrete Sandwich Façade Elements. International Journal of Concrete Structures and Materials, 12(1), Article ID 71.
Open this publication in new window or tab >>Composite Behaviour of Textile Reinforced Reactive Powder Concrete Sandwich Façade Elements
2018 (English)In: International Journal of Concrete Structures and Materials, ISSN 1976-0485, E-ISSN 2234-1315, Vol. 12, no 1, article id 71Article in journal (Refereed) Published
Abstract [en]

Within the EC funded project smart elements for sustainable building envelopes, carbon textile reinforcement was incorporated into reactive powder concrete, namely textile reinforced reactive powder concrete (TRRPC), to additionally improve the post-cracking behaviour of the cementitious matrix. This high-performance composite material was included as outer and inner façade panels in prefabricated and non-load bearing sandwich elements along with low density foamed concrete (FC) and glass fibre reinforced polymer continuous connecting devices. Experiments and finite element analysis (FEA) were applied to characterize the structural performance of the developed sandwich elements. The mechanical behaviour of the individual materials, components and large-scale elements were quantified. Four-point bending tests were performed on large-scale TRRPC-FC sandwich element beams to quantify the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on digital image correlation were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behaviour 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. As for the FEA, the applied modelling approach was found to accurately describe the stiffness of the sandwich elements at lower load levels, while describing the stiffness in a conservative manner after the occurrence of connector failure mechanisms. © 2018, The Author(s).

Keywords
finite element analysis (FEA), foam concrete (FC), four-point bending test, reactive powder concrete (RPC), sandwich elements, textile reinforced concrete (TRC), Bending tests, Cracks, Fiber reinforced plastics, Finite element method, Intelligent buildings, Optical correlation, Reinforced concrete, Sandwich structures, Stiffness, Structural analysis, Textiles, Foam concretes, Reactive powder concrete, Sandwich element, Textile reinforced concretes, Failure (mechanical)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36594 (URN)10.1186/s40069-018-0301-4 (DOI)2-s2.0-85057099836 (Scopus ID)
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2018-12-06Bibliographically approved
Mathern, A., Flansbjer, M., Löfgren, I. & Magnusson, J. (2018). EXPERIMENTAL STUDY OF TIME-DEPENDENTPROPERTIES OF A LOW-PH CONCRETE FOR DEPOSITIONTUNNELS. In: : . Paper presented at The International Federation for Structural Concrete 5th International fib Congress.
Open this publication in new window or tab >>EXPERIMENTAL STUDY OF TIME-DEPENDENTPROPERTIES OF A LOW-PH CONCRETE FOR DEPOSITIONTUNNELS
2018 (English)Conference paper, Published paper (Refereed)
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.

Keywords
Creep, Low-pH, Material properties, Self-compacting concrete, Shrinkage, Silica fume
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:ri:diva-35556 (URN)
Conference
The International Federation for Structural Concrete 5th International fib Congress
Funder
Swedish Nuclear Fuel and Waste Management Company, SKB
Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Flansbjer, M. & Lindqvist, J. E. (2018). Meso Mechanical Study of Cracking Process in Concrete Subjected toTensile Loading. Nordic Concrete Research, 59(2), 13-29
Open this publication in new window or tab >>Meso Mechanical Study of Cracking Process in Concrete Subjected toTensile Loading
2018 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 59, no 2, p. 13-29Article in journal (Other academic) Published
Abstract [en]

This project focused on how the cracking process in concrete is influenced by both the micro and meso structures of concrete. The aim was to increase knowledge pertaining to the effect of critical parameters on the cracking process and how this is related to the material's macroscopic properties. A methodology based on the combination of different experimental methods and measuring techniques at different scales was developed. Crack propagation during tensile loading of small-scale specimens in a tensile stage was monitored by means of Digital Image Correlation (DIC) and Acoustic Emission (AE). After testing, crack patterns were studied using fluorescence microscopy.

Place, publisher, year, edition, pages
Oslo: , 2018
Keywords
Concrete, Cracking, Testing, Digital Image Correlation, Acoustic Emission
National Category
Materials Engineering Infrastructure Engineering Building Technologies
Identifiers
urn:nbn:se:ri:diva-37683 (URN)10.2478/ncr-2018-0012 (DOI)
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2019-01-30 Created: 2019-01-30 Last updated: 2019-02-08Bibliographically approved
Flansbjer, M. & Williams Portal, N. (2017). 3D Analysis of Strains in Fibre Reinforced Concrete Using X-Ray Tomography and Digital Volume Correlation. In: : . Paper presented at XXIII Nordic Concrete Research Symposium, Aalborg, Denmark.
Open this publication in new window or tab >>3D Analysis of Strains in Fibre Reinforced Concrete Using X-Ray Tomography and Digital Volume Correlation
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In fibre reinforced concrete (FRC), understanding the underlying interaction mechanisms between discrete fibres and the surrounding concrete matrix can lead to the optimization of the fibre-matrix combination. This paper presents the initial development of a method enabling the analysis of this given interaction on ameso-mechanical level. The method is such that volume images are initially captured using X-ray Computed Tomography (XCT) on small-scale FRC specimens under loading which are thereafter analysed to measure full 3D strainand deformation via Digital Volume Correlation (DVC). It is anticipated that the method developed in this project can be a useful tool for the developmentof new innovative and high performance FRC.

Keywords
Fibre reinforced concrete, pull-out behaviour, X-ray Computed Tomography, Digital Volume Correlation
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:ri:diva-35559 (URN)
Conference
XXIII Nordic Concrete Research Symposium, Aalborg, Denmark
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3481-1368

Search in DiVA

Show all publications
v. 2.35.7