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Mohammadi Mohaghegh, A., Silfwerbrand, J. & Årskog, V. (2018). Shear behavior of high-performance basalt fiber concrete—Part I: Laboratory shear tests on beams with macro fibers and bars. Structural Concrete, 19(1), 246-254
Open this publication in new window or tab >>Shear behavior of high-performance basalt fiber concrete—Part I: Laboratory shear tests on beams with macro fibers and bars
2018 (English)In: Structural Concrete, ISSN 1464-4177, E-ISSN 1751-7648, Vol. 19, no 1, p. 246-254Article in journal (Refereed) Published
Abstract [en]

This paper presents findings from an experimental study on shear properties of high-performance concrete beams reinforced with basalt fiber reinforced polymer bars and macrobasalt fibers. The test specimens comprised seven beams for shear testing and five beams for measuring the residual tensile strength of fiber concrete. No stirrups were used in the test beams. As part of the experiments, the compressive strength and bulk electrical resistivity were measured. To assess the influence of fiber dosage on shear capacity of concrete beams, five-volume fractions of 43 mm macrobasalt fibers were investigated. The experimental results verified the hypothesis that shear capacity of concrete beams is associated with the fiber dosage. Furthermore, the results show a good correspondence with the predictions of Swedish standard (SS 812310:2014) and the fib Model Code 2010 predictions of shear strength of fiber reinforced concrete beams without shear stirrups. 

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
basalt fiber reinforced polymer (BFRP) bars, fib model code (MC) 2010, high-performance concrete (HPC), macrobasalt fibers (MBF), shear behavior, Swedish standard (SS 812310:2014), Basalt, Beams and girders, Compressive strength, Concrete beams and girders, Concrete testing, Concretes, Fiber reinforced materials, Fiber reinforced plastics, Fibers, Reinforced concrete, Reinforced plastics, Tensile strength, Tensile testing, Basalt fiber, Fib model codes, Swedishs, High performance concrete
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-227446 (URN)10.1002/suco.201700208 (DOI)000428463600019 ()2-s2.0-85044362798 (Scopus ID)
Note

Export Date: 9 May 2018; Article; Correspondence Address: Mohammadi Mohaghegh, A.; Department of Civil and Architectural Engineering, KTH Royal Institute of TechnologySweden; email: ali.m.mohaghegh@outlook.com. QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-05-28Bibliographically approved
Mohammadi Mohaghegh, A. & Silfwerbrand, J. (2017). Fire Spalling of High-Performance Basalt Fibre Concrete. Nordic Concrete Research, 57(2), 89-102
Open this publication in new window or tab >>Fire Spalling of High-Performance Basalt Fibre Concrete
2017 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 57, no 2, p. 89-102Article in journal (Refereed) Published
Abstract [en]

The use of Macro Basalt Fibre Concrete (MBFC) for structural purposes is increasing in the Norwegian market. However, findings on properties related to fire spalling are scarce in the literature. Motivated by this, the authors present the results of a pilot experimental study on fire spalling properties of two types of basalt fibre concrete. The study results show that basalt fibres cannot prevent high-performance concrete (HPC) from fire spalling. Nonetheless, the comparison of the average spalling values indicates that use of basalt fibres probably does not increase the spalling propensity of the tested materials.

Place, publisher, year, edition, pages
Oslo, Norway: nordic concrete federation, 2017
Keywords
Macro basalt fibres, chopped basalt fibres, high-performance concrete (HPC), fire spalling
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-221655 (URN)000425406800008 ()
Note

QC 20180119

Available from: 2018-01-18 Created: 2018-01-18 Last updated: 2018-03-14Bibliographically approved
Mohammadi Mohaghegh, A. (2017). Flexural Behaviour of Medium-Strength and High-Performance Macro Basalt Fibre Concrete Aimed for Marine Applications. Nordic Concrete Research (57), 103-123, Article ID 2.
Open this publication in new window or tab >>Flexural Behaviour of Medium-Strength and High-Performance Macro Basalt Fibre Concrete Aimed for Marine Applications
2017 (English)In: Nordic Concrete Research, ISSN 0800-6377, no 57, p. 103-123, article id 2Article in journal (Refereed) Published
Abstract [en]

This paper addresses the flexural behaviour of medium-strength, and high-performance concrete (HPC) reinforced with macro fibres made of basalt fibre reinforced polymer (BFRP) with the intended use for marine applications. Mechanical properties of the fibre concrete were studied through an experimental programme consisting of 18 beam specimens and 45-cylinder samples. In this study two types of concrete were used; medium-strength and high-performance concrete with the compressive strength of approximately 60-75 MPa and 90-105 MPa, respectively. The aspect-ratio of the used fibres were 65 and 83, respectively. The experimental results show that the post-cracking properties of macro basalt fibre concrete is a function of the fibre volume content.

Place, publisher, year, edition, pages
Oslo, Norway: , 2017
Keywords
Macro basalt fibres, high-performance concrete (HPC), flexural behaviour, toughness, ductility, durability, marine structures
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-221654 (URN)000425406800009 ()
Note

QC 20180119

Available from: 2018-01-18 Created: 2018-01-18 Last updated: 2018-03-14Bibliographically approved
de Frias Lopez, R., Ekblad, J. & Silfwerbrand, J. (2016). A Numerical Study on the Permanent Deformation of Gap-Graded Granular Mixtures. In: J. Pombo (Ed.), Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance. Paper presented at Third International Conference on Railway Technology: Research, Development and Maintenance. Stirlingshire, UK: Civil-Comp Press
Open this publication in new window or tab >>A Numerical Study on the Permanent Deformation of Gap-Graded Granular Mixtures
2016 (English)In: Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance / [ed] J. Pombo, Stirlingshire, UK: Civil-Comp Press , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Permanent deformation accumulation of unbound granular layers under traffic plays a critical role in the performance and need for maintenance of pavements and railway structures. In this paper, the discrete element method is used to study the permanent strain behaviour of binary mixtures of elastic spheres, as an idealization of gap-graded mixtures, under triaxial monotonic loading. The effects of stress level and soil fabric structure, based on a recently proposed classification system founded on micromechanical considerations, are assessed by subjecting mixtures with varying fines contents to different stress levels. Additionally, mixtures are loaded to static failure to study the dependency of the permanent strains on the closeness of the applied stress to failure stress, in accordance with existing empirical models. Numerical results are also compared with the experimentally determined behaviour of granular materials. The findings indicate that numerical mixtures are able to reproduce some of the most significant features observed in laboratory tests on granular materials, further encouraging the use of numerical simulations to enhance the understanding of granular media behaviour. Additionally, a good correlation between fabric structure and performance is obtained, giving additional support to the use of the studied fabric classification system for performance characterization.

Place, publisher, year, edition, pages
Stirlingshire, UK: Civil-Comp Press, 2016
Series
Civil-Comp Proceedings, ISSN 1759-3433
Keywords
granular mixtures, permanent deformation, discrete element method, fabric of soils, static strength
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-185172 (URN)10.4203/ccp.110.15 (DOI)2-s2.0-84964355508 (Scopus ID)
Conference
Third International Conference on Railway Technology: Research, Development and Maintenance
Note

QC 20160419

Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2016-11-15Bibliographically approved
de Frias Lopez, R., Silfwerbrand, J., Jelagin, D. & Birgisson, B. (2016). Force transmission and soil fabric of binary granular mixtures. Geotechnique, 66(7), 578-583
Open this publication in new window or tab >>Force transmission and soil fabric of binary granular mixtures
2016 (English)In: Geotechnique, ISSN 0016-8505, E-ISSN 1751-7656, Vol. 66, no 7, p. 578-583Article in journal (Refereed) Published
Abstract [en]

The effect of fines content on force transmission and fabric development of gap-graded mixtures under triaxial compression has been studied using the discrete-element method. Results were used to define load-bearing soil fabrics where the relative contributions of coarse and fine components are explicitly quantified in terms of force transmission. Comparison with previous findings suggests that lower particle size ratios result in higher interaction between components. A potential for instability was detected for underfilled fabrics in agreement with recent findings. It was also found that the threshold fines content provides an accurate macroscopic estimation of the transition between underfilled and overfilled fabrics.

Place, publisher, year, edition, pages
ICE Publishing, 2016
Keywords
discrete-element modelling, fabric/structure of soils, particle-scale behaviour
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-185171 (URN)10.1680/jgeot.14.P.199 (DOI)000377361700005 ()
Note

QC 20160721

Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-11-30Bibliographically approved
Silfwerbrand, J. (2016). Is debonding in concrete pavements unavoidable?. In: RILEM Bookseries: (pp. 599-604). Springer Netherlands
Open this publication in new window or tab >>Is debonding in concrete pavements unavoidable?
2016 (English)In: RILEM Bookseries, Springer Netherlands , 2016, p. 599-604Conference paper (Refereed)
Abstract [en]

Concrete overlays constitute one of the most frequent measures to repair and strengthen concrete bridge decks, concrete pavements, and industrial concrete floors. Good, secure, and durable bond between overlay and substrate provides the prerequisite for monolithic action and improves the durability. 30 years of Swedish research on bonded overlays thought beam tests, slab tests, and field measurements shows that a good bond can be obtained if some important demands are fulfilled. The Swedish research also includes long-term studies on repaired concrete bridge decks. These studies show that the bond is of the same magnitude ten years after concrete repair independent of structural system of the bridge, climate zone, traffic volume, or use of de-icing salt. Laboratory studies show that good bond is also able to resist fatigue loading. This paper summarizes these research activities and provides heavy arguments for answering the question in the heading negatively. Debonding is not unavoidable. 

Place, publisher, year, edition, pages
Springer Netherlands, 2016
Keywords
Bond, Field tests, Laboratory tests, Longterm studies
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-216857 (URN)10.1007/978-94-024-0867-6_84 (DOI)2-s2.0-85029574636 (Scopus ID)
Note

Export Date: 24 October 2017; Article; Correspondence Address: Silfwerbrand, J.L.; Department of Civil and Architectural Engineering, Division of Concrete Structures, KTH Royal Institute of TechnologySweden; email: jsilfwer@kth.se. QC 20171128

Available from: 2017-11-28 Created: 2017-11-28 Last updated: 2017-11-28Bibliographically approved
Mancera, R. & Silfwerbrand, J. (2016). Maintenance-friendliness in management of civil engineering structures. In: IABSE Congress Stockholm, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment. Paper presented at 19th IABSE Congress Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, 21 September 2016 through 23 September 2016 (pp. 1469-1476). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Maintenance-friendliness in management of civil engineering structures
2016 (English)In: IABSE Congress Stockholm, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, International Association for Bridge and Structural Engineering (IABSE) , 2016, p. 1469-1476Conference paper (Refereed)
Abstract [en]

Cost efficiency and reliability are mayor concerns in structural engineering, e.g. bridges. Acquisition costs depend strongly on buildability. Traditional approaches to lower maintenance costs are efficient maintenance and robust or maintenance-free design, normally expensive. This study's approach is systematic and successive life-cycle assessment of reliability, availability, maintainability, safety (RAMS) and sustainability (LCCA, e-LCA, s-LCA, risk and legitimacy). IMF (index of maintenance-friendliness), IAC (algorithm for the identification of collateral components) can be used to quantify maintainability, e.g. low accessibility for inspection or operation, unease to operate, unsafety, etc. A holistic model has been suggested to confront these concerns in urban development. More than simplifying complexity, the authors suggest to deal with it.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2016
Keywords
Buildability, Complexity, Life-cycle, Maintenance-friendliness, Mimetic, RAMS, Reliance, Risk, Sustainability, Cost engineering, Costs, Life cycle, Maintainability, Maintenance, Random access storage, Risk assessment, Risks, Sustainable development, Urban growth, Civil engineering structures, Life Cycle Assessment (LCA), Lower maintenance costs, Traditional approaches, Bridges
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-216854 (URN)2-s2.0-85018940032 (Scopus ID)9783857481444 (ISBN)
Conference
19th IABSE Congress Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, 21 September 2016 through 23 September 2016
Note

Conference code: 127207; Export Date: 24 October 2017; Conference Paper; Correspondence Address: Mancera, R.; Nacka MunicipalitySweden; email: rafael.mancera@nacka.se. QC 20171114

Available from: 2017-11-14 Created: 2017-11-14 Last updated: 2017-11-14Bibliographically approved
Döse, M., Silfwerbrand, J., Jelinek, C., Trägårdh, J. & Isaksson, M. (2016). Naturally occurring radioactivity in some Swedish concretes and their constituents: Assessment by using I-index and dose-model. Journal of Environmental Radioactivity, 155-156, 105-111
Open this publication in new window or tab >>Naturally occurring radioactivity in some Swedish concretes and their constituents: Assessment by using I-index and dose-model
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2016 (English)In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 155-156, p. 105-111Article in journal (Refereed) Published
Abstract [en]

The reference level for effective dose due to gamma radiation from building materials and construction products used for dwellings is set to 1 mSv per year (EC, 1996, 1999), (CE, 2014). Given the specific conditions presented by the EC in report 112 (1999) considering building and construction materials, an I-index of 1 may generate an effective dose of 1 mSv per year. This paper presents a comparison of the activity concentrations of 4 0K, 226Ra and 232Th of aggregates and when these aggregates constitute a part of concrete. The activity concentration assessment tool for building and construction materials, the I-index, introduced by the EC in 1996, is used in the comparison. A comparison of the I-indices values are also made with a recently presented dose model by Hoffman (2014), where density variations of the construction material and thickness of the construction walls within the building are considered. There was a ~16-19% lower activity index in concretes than in the corresponding aggregates. The model by Hoffman further implies that the differences between the I-indices of aggregates and the concretes' final effective doses are even larger. The difference is due, mainly to a dilution effect of the added cement with low levels of natural radioisotopes, but also to a different and slightly higher subtracted background value (terrestrial value) used in the modeled calculation of the revised I-index by Hoffman (2014). Only very minimal contributions to the annual dose could be related to the water and additives used, due to their very low content of radionuclides reported.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Aggregates, Building materials, Concrete, Construction product, Dose model, I-index, Radioactivity
National Category
Environmental Analysis and Construction Information Technology
Identifiers
urn:nbn:se:kth:diva-186973 (URN)10.1016/j.jenvrad.2016.02.012 (DOI)000374358100014 ()2-s2.0-84960957052 (Scopus ID)
Note

QC 20160518

Available from: 2016-05-18 Created: 2016-05-16 Last updated: 2017-11-30Bibliographically approved
Gram, A., Silfwerbrand, J. L. & Lagerblad, B. (2016). Particle motion in fluid: Analytical and Numerical Study. Applied Rheology, 26(2)
Open this publication in new window or tab >>Particle motion in fluid: Analytical and Numerical Study
2016 (English)In: Applied Rheology, ISSN 1430-6395, E-ISSN 1617-8106, Vol. 26, no 2Article in journal (Refereed) Published
Abstract [en]

Particle motion in fluid is discussed for one-particle systems as well as for dense suspensions, such as cementitious materials. The difference in large particle motion between larger particles and behaviour of fines (<125 μm) is explained, motion of one particle is shown by numerical simulation. It is concluded and highlighted that it is the particular motion of the fines that to a large extent contribute to the rheological properties of a suspension. It is also shown why larger ellipsoidal particles do not necessarily contribute to the increase of viscosity.

Place, publisher, year, edition, pages
Kerschensteiner Verlag GmbH, 2016
Keywords
Bingham model, Cementitious material, Suspensional flow
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-188244 (URN)10.3933/APPLRHEOL-26-23326 (DOI)000377149700006 ()2-s2.0-84963591618 (Scopus ID)
Note

QC 20160613

Available from: 2016-06-13 Created: 2016-06-09 Last updated: 2017-11-28Bibliographically approved
de Frias Lopez, R., Ekblad, J. & Silfwerbrand, J. (2016). Resilient properties of binary granular mixtures: A numerical investigatio. Computers and geotechnics, 76, 222-233
Open this publication in new window or tab >>Resilient properties of binary granular mixtures: A numerical investigatio
2016 (English)In: Computers and geotechnics, ISSN 0266-352X, E-ISSN 1873-7633, Vol. 76, p. 222-233Article in journal (Refereed) Published
Abstract [en]

The effect of stress level on the resilient modulus for binary mixtures of elastic spheres under triaxial loading is investigated using the discrete element method. The secant modulus during the first cycle of unloading is used as an estimate of the modulus after several load cycles due to computational time restrains. Later in the paper, its adequacy as an accurate and efficient estimator is shown. Numerical results are statistically compared with existing relations characterizing the stress dependency of the resilient modulus for real granular materials. It is concluded that the modulus prediction is significantly improved considering the effect of the deviator stress in addition to the confinement stress, obtaining a good correlation between the modulus and the confinement to deviator stress ratio for the numerical mixtures. The stress dependency of a recently proposed soil fabric classification system, based on force transmission considerations at particulate level, is also studied and its correlation with performance investigated. It is found that the relative load-bearing role of coarse and fine components is governed by the deviator to confinement stress ratio. However, the implemented fabric classification is fairly insensitive to changes in this ratio. Regarding resilient performance, interactive fabrics show the stiffest response whereas underfilled fabrics should be avoided due to a potential for instability.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Discrete element modelling, Fabric of soils, Granular mixtures, Resilient modulus
National Category
Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-186145 (URN)10.1016/j.compgeo.2016.03.002 (DOI)2-s2.0-84963737153 (Scopus ID)
Note

QC 20160511

Available from: 2016-05-03 Created: 2016-05-03 Last updated: 2017-11-30Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1526-9331

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