Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 149) Show all publications
Ahmed, L. (2018). Dynamic Measurements for Determining Poisson’s Ratio of Young Concrete. Nordic Concrete Research (58), 95-105
Open this publication in new window or tab >>Dynamic Measurements for Determining Poisson’s Ratio of Young Concrete
2018 (English)In: Nordic Concrete Research, ISSN 0800-6377, no 58, p. 95-105Article in journal (Refereed) Published
Abstract [en]

Knowledge of the elastic properties of concrete at early age is often a pre-requisite for numerical calculations. This paper discusses the use of a laboratory technique for determining Poisson’s ratio at early concrete age. A non-destructive test set-up using the impact resonance method has been tested and evaluated. With the method, it has been possible to obtain results already at 7 hours of concrete age. Poisson's ratio is found to decrease sharply during the first 24 hours to reach a value of 0.08 and then increase to approximately 0.15 after seven days.

National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-235278 (URN)
Note

QC 20180920

Available from: 2018-09-19 Created: 2018-09-19 Last updated: 2018-09-20Bibliographically approved
Döse, M. & Silfwerbrand, J. (2018). Reduction of Radon Gas in Concrete Using Admixtures and Additives. Betong, 58(1), 17-34
Open this publication in new window or tab >>Reduction of Radon Gas in Concrete Using Admixtures and Additives
2018 (English)In: Betong, Vol. 58, no 1, p. 17-34Article in journal (Refereed) Published
Abstract [en]

The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined three concrete recipes where only an additive as well as fly ash were added as single constituents to a reference recipe and compared to a reference concrete. The inputs of an additive as well as a supplementary cementitious material (fly ash) were made as a mean to investigate their potential influence on the radon exhalation rates of the concrete. Measurements were performed with an ATMOS 33 ionizing pulsation chamber for at least five different occasions for each recipe during a 22 month period. The results indicate a reduction of the exhalation rate by approximately 30-35 % for each altered recipe. This means roughly 1.5-2 mSv per year decrease in effective dose to a human using an additive or a supplementary cementitious material such as fly ash in relation to the investigated standard concrete.

Place, publisher, year, edition, pages
Betong Media AB: , 2018
Keywords
Radon, effective dose, concrete, building materials, admixtures, additives, fly ash, health.
National Category
Building Technologies
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-233815 (URN)
Note

QC 20180903

Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-09-03Bibliographically approved
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
Döse, M. & Silfwerbrand, J. (2018). Supplementary Cementitious Materials and Additives – Effective Measures to Hinder Radon in Concrete. In: : . Paper presented at Conference paper - presented at the IRPA (International Radiological Protection Association) Conference 2018- June, den Hague (pp. 8). USA: Gudapuris
Open this publication in new window or tab >>Supplementary Cementitious Materials and Additives – Effective Measures to Hinder Radon in Concrete
2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined ten different concrete recipes containing an additive or Supplementary Cementious Material (SCM), such as fly ash, slag or silica and combinations thereof. The SCM´s were added in small to moderate portions and substituted the reference Portland cement (OPC). The inputs of an additive as well as a supplementary cementitious material were made as a mean to investigate their potential influence on the radon exhalation rates of the concrete as well as the radon gas diffusion length (L) that could be expected from the different recipes. Measurements were performed with an ATMOS 33 ionizing pulsation chamber. The results indicate a reduction of the exhalation rate by approximately 10-55 % depending on recipe at an RH of 75 %. The diffusion coefficients, corrected for background subtraction vary in the interval 1.1 x 10-10 – 7.6 x 10-12 m2/s. The diffusion lengths vary between 2 and 9 mm. In the case where the largest reduction of the exhalation rate is achieved, this roughly correspond to >2 mSv per year decrease in effective dose to a human. Consequently, using an additive or a SCM, as part of the mix, would be an option to effectively lower the radon gas exhalation in their initial stage of production. Secondly, the use of additives and SCM´s will contribute to a lower environmental impact (CO2).

Place, publisher, year, edition, pages
USA: Gudapuris, 2018
Keywords
Radon; Effective Dose; Building Materials, Radon Gas Diffusion Length; Additives
National Category
Building Technologies
Research subject
Civil and Architectural Engineering; Real Estate and Construction Management
Identifiers
urn:nbn:se:kth:diva-233816 (URN)
Conference
Conference paper - presented at the IRPA (International Radiological Protection Association) Conference 2018- June, den Hague
Note

QC 20180903

Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-09-03Bibliographically 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
Döse, M. & Silfwerbrand, J. (2017). Reduction of radon gas in concrete – effects and evaluation of effective dose. In: Marianne Tange Hasholt (Ed.), Nordic Concrete Research: . Paper presented at Nordic Concrete Research, Proceedings of the XXIII Nordic Concrete Research Symposium, Aalborg, Denmark 2017 (pp. 185-188). Oslo, Norway, 1
Open this publication in new window or tab >>Reduction of radon gas in concrete – effects and evaluation of effective dose
2017 (English)In: Nordic Concrete Research / [ed] Marianne Tange Hasholt, Oslo, Norway, 2017, Vol. 1, p. 185-188Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined two identical concrete recipes where only an additive, X1002 Hycrete hydrophobant corrosion inhibitor was added to one of the recipes as a mean to lower the radon exhalation rate. Measurements were performed with an ATMOS 33 ionizing pulsation chamber at four different occasions for each recipe during 12 months. The results indicate a reduction of the exhalation rate by approximately 30-35 %, meaning roughly 2 mSv per year decrease in effective dose to a human.

Place, publisher, year, edition, pages
Oslo, Norway: , 2017
National Category
Building Technologies
Identifiers
urn:nbn:se:kth:diva-233819 (URN)
Conference
Nordic Concrete Research, Proceedings of the XXIII Nordic Concrete Research Symposium, Aalborg, Denmark 2017
Note

QC 20180903

Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-09-03Bibliographically 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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1526-9331

Search in DiVA

Show all publications