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Publications (8 of 8) Show all publications
Rogers, P., Silfwerbrand, J., Gram, A. & Selander, A. (2019). Bulk hydrophobic civil engineering concrete for nordic conditions – Freeze thaw action. In: Proceedings of the fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures. Paper presented at fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures, 27 May 2019 through 29 May 2019 (pp. 2044-2051). International Federation for Structural Concrete
Open this publication in new window or tab >>Bulk hydrophobic civil engineering concrete for nordic conditions – Freeze thaw action
2019 (English)In: Proceedings of the fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures, International Federation for Structural Concrete , 2019, p. 2044-2051Conference paper, Published paper (Refereed)
Abstract [en]

Concrete is a composite building material which long term function can be modified for example by changing the water to cement ratio (w/c) or by adding in other chemical admixtures to change the fresh and hardened properties of the concrete. The overall goal of this study is to reduce the water absorption capacity of the cement paste/microstructure by at least 85 %. This is achieved by using bulk hydrophobic agents in the mixing phase rather than post hardened surface application. Numerous commercial agents and triglycerides (vegetable oils) were tested and showed promising results at a dosage equal to 3% of cement weight. This though affected compressive strengths negatively. As these concretes will be exposed to Nordic winter conditions, the concrete should perform well under repeated salt water freezing and thawing. This continued study will show how a selection of these bulk hydrophobic concretes performed during this part of the study. The concrete has a w/c = 0.4 with a cement content (CEM I) of 430 kg/m3.

Place, publisher, year, edition, pages
International Federation for Structural Concrete, 2019
Keywords
Air pores, Bulk hydrophobic concrete, Freeze thaw action, Silanes, Thin section analysis, Triglycerides, Vegetable oils, Cements, Compressive strength, Concrete additives, Freezing, Hardening, Hydrophobicity, Thawing, Water absorption, Composite building materials, Freeze thaw actions, Fresh and hardened properties, Thin section, Water absorption capacity, Water-to-cement ratios, Concretes
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38967 (URN)2-s2.0-85066107127 (Scopus ID)9782940643004 (ISBN)
Conference
fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures, 27 May 2019 through 29 May 2019
Note

 Funding details: Bundesamt für Berufsbildung und Technologie; Funding details: Stiftelsen Bergteknisk Forskning; Funding text 1: The authors would like to thank BBT (Swedish Transport Agency) and BeFo (Rock Engineering Research Foundation) for their continued financial support.

Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2019-08-13Bibliographically approved
Roussel, N., Gram, A., Cremonesi, M., Ferrara, L., Krenzer, K., Mechtcherine, V., . . . Vasilic, K. (2016). Numerical simulations of concrete flow: A benchmark comparison. Cement and Concrete Research, 79, 265-271
Open this publication in new window or tab >>Numerical simulations of concrete flow: A benchmark comparison
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2016 (English)In: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 79, p. 265-271Article in journal (Refereed) Published
Abstract [en]

First, we define in this paper two benchmark flows readily usable by anyone calibrating a numerical tool for concrete flow prediction. Such benchmark flows shall allow anyone to check the validity of their computational tools no matter the numerical methods and parameters they choose. Second, we compare numerical predictions of the concrete sample final shape for these two benchmark flows obtained by various research teams around the world using various numerical techniques. Our results show that all numerical techniques compared here give very similar results suggesting that numerical simulations of concrete filling ability when neglecting any potential components segregation have reached a technology readiness level bringing them closer to industrial practice.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
casting, fresh concrete, modeling, rheology, workability
National Category
Civil Engineering Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:ri:diva-357 (URN)10.1016/j.cemconres.2015.09.022 (DOI)2-s2.0-84948461571 (Scopus ID)
Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2019-06-17Bibliographically approved
Gram, A., Silfwerbrand, J. & 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
Civil Engineering Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:ri:diva-385 (URN)10.3933/APPLRHEOL-26-23326 (DOI)2-s2.0-84963591618 (Scopus ID)
Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2019-06-17Bibliographically approved
Kraft, L., Rogers, P., Eriksson Brandels, A., Gram, A., Trädgårdh, J. & Wallqvist, V. (2015). Experimentalrubber chip concrete mixes for shock absorbent bike lane pavements.. In: : . Paper presented at 3rd International Conference on Best Practices for Concrete Pavements, 28 - 30 October. 2015. Bonito, Brazil: IBRACON and USP..
Open this publication in new window or tab >>Experimentalrubber chip concrete mixes for shock absorbent bike lane pavements.
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2015 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In Sweden the amount of cyclists being injured in traffic has increased in recent years. Over 23,000 peopleper annum visit an acute care hospital after being injured whilst cycling. Most bicycle accidents are single“vehicle” accidents (82 %) and the most common collision is with another cyclist. Due to increased healthcare costs and the fact that more city dwelling people choose to cycle instead of going by car - due both tomonetary, environmental and personal health reasons - one is devoted to find solutions to make cyclingsafer. Besides efforts to increase helmet usage among cyclists and safer bike lane design separate from cartraffic, another way to reduce injuries may be achieved by modifying the bike lanes’ properties. This wouldresult in safer cycling and not only reducing non-cranial injuries, but also limit the severity of head injuries forcyclists not wearing a helmet. Thus, the pavement and bicycle lane material must be an efficient absorbentof impact energy. The work here presents efforts on modifying a concrete pavement by replacing coarseaggregates and sand with rubber chips and rubber crumbs to increase the shock absorbent capacity.Altogether, eighteen different mixtures with varying proportions of rubber, cement and sand were preparedand evaluated regarding elastic modulus and compressive strength. A fly-ash cement, microsilica and latexsolution were used in the concrete mixes. From the results obtained the mix with the best impact absorbingproperties, with a low E-modulus and sufficient compressive strength, was chosen for further evaluation.

Series
IBRACON, ISSN 2175-8182
Keywords
Rubber chips, rubber crumbs, rubber modified concrete, bike lane
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39891 (URN)
Conference
3rd International Conference on Best Practices for Concrete Pavements, 28 - 30 October. 2015. Bonito, Brazil: IBRACON and USP.
Available from: 2019-09-06 Created: 2019-09-06 Last updated: 2019-09-06Bibliographically approved
Gram, A. & Silfwerbrand, J. (2014). Obtaining rheological parameters from flow test: analytical, computational and lab test approach (ed.). Cement and Concrete Research, 63, 29-34
Open this publication in new window or tab >>Obtaining rheological parameters from flow test: analytical, computational and lab test approach
2014 (English)In: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 63, p. 29-34Article in journal (Refereed) Published
Abstract [en]

In the mix design process of cementitious suspensions, an adequate rheology of the cement paste is crucial. A novel rheological field test device for cementitious fluids is presented here and investigated theoretically, by computer simulation and by lab tests. A simple flow stoppage test with a timed spread passage point provides accurate rheological parameters according to the Bingham material model. Values for yield stress and plastic viscosity are obtained for a test specimen of no more than 19.75 · 10- 6 m3 of fluid. This volume is equivalent to 19.75 g of water at room temperature. Such a small volume allows reliable tests even for small amounts of fillers. Promising results show that both yield stress and plastic viscosity can be determined by this simple test. This novel rheological test method also enables the correlation of different rheological equipment used by different laboratories.

Keywords
Cement paste, Modeling (E), Mortar (E), Rheology (A), Simulation, Workability Bingham material model (A)
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:ri:diva-2696 (URN)10.1016/j.cemconres.2014.03.012 (DOI)2-s2.0-84900990005 (Scopus ID)4690 (Local ID)4690 (Archive number)4690 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2019-08-13Bibliographically approved
Mechtcherine, V., Gram, A., Krenzer, K., Schwabe, J.-H., Shyshko, S. & Roussel, N. (2014). Simulation of fresh concrete flow using Discrete Element Method (DEM): theory and applications (ed.). Materials and Structures, 47(4), 615-630
Open this publication in new window or tab >>Simulation of fresh concrete flow using Discrete Element Method (DEM): theory and applications
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2014 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 47, no 4, p. 615-630Article in journal (Refereed) Published
Abstract [en]

This article provides an overview of the development and the contemporary state of research in the field of simulating fresh concrete flow using the Discrete Element Method (DEM). First, this work originating from TC 222-SCF simulation of fresh concrete flow, covers the mathematical methodology, the identification of the model parameters and the link between the rheological properties of fresh concrete and the parameters of DEM-based models. Various examples of the estimation of model parameters and calibration of the model were demonstrated, followed by verifications by comparing the numerical results and the corresponding predictions by analytical formula and laboratory experiments. Furthermore, software used in concrete engineering and existing industrial applications of the developed particle models were described, showing the potential of DEM.

Keywords
Distinct Element Method, Fresh concrete, Numerical simulation, Rheology
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:ri:diva-2711 (URN)10.1617/s11527-013-0084-7 (DOI)2-s2.0-84895930606 (Scopus ID)4030 (Local ID)4030 (Archive number)4030 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2019-08-08Bibliographically approved
Gram, A. & Silfwerbrand, J. (2010). Applications for numerical simulation of self-compacting concrete (ed.). Nordic Concrete Research, 42(2), 143-154
Open this publication in new window or tab >>Applications for numerical simulation of self-compacting concrete
2010 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 42, no 2, p. 143-154Article in journal (Other academic) Published
Keywords
numerical simulation, analytical channel flow solution, SCC, casting, Rheo-Box
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:ri:diva-2673 (URN)5023 (Local ID)5023 (Archive number)5023 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2018-08-16Bibliographically approved
Gram, A. (2009). SKB utvecklas inom teori och praktik (ed.). Betong (5), 43-45
Open this publication in new window or tab >>SKB utvecklas inom teori och praktik
2009 (Swedish)In: Betong, ISSN 1101-9190, no 5, p. 43-45Article in journal (Other academic) Published
Keywords
självkompakterande betong
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:ri:diva-2555 (URN)4912 (Local ID)4912 (Archive number)4912 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2018-08-16Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5901-1586

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