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Publications (9 of 9) Show all publications
Nilsson, M., Nilimaa, J., Emborg, M., Hösthagen, A. & Westerholm, M. (2024). Analysmetodik och materialmodeller vid inmätning av ung betongs egenskaper för beräkning av temperatur, hållfasthet och spänningar under härdningsförlopp. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Analysmetodik och materialmodeller vid inmätning av ung betongs egenskaper för beräkning av temperatur, hållfasthet och spänningar under härdningsförlopp
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2024 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2024. p. 102
Series
Technical report / Luleå University of Technology, ISSN 1402-1536
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Building Materials
Identifiers
urn:nbn:se:ltu:diva-108191 (URN)978-91-8048-611-8 (ISBN)
Projects
Trafikverkets och Anläggning AMAs metoder för undvikande av tidig sprickbildning i betong – nyutveckling med hänsyn till miljökriterier
Funder
Swedish Transport Administration, FOI-BBTSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Funder: Heidelberg Materials, Cement och Betong

Available from: 2024-06-28 Created: 2024-06-28 Last updated: 2024-07-02Bibliographically approved
Nilsson, M., Nilimaa, J., Emborg, M., Hösthagen, A. & Westerholm, M. (2024). Materialdata för beräkning av temperatur, hållfasthet och spänningar – betong med AnlFA-cement, flygaska och slagg. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Materialdata för beräkning av temperatur, hållfasthet och spänningar – betong med AnlFA-cement, flygaska och slagg
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2024 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2024. p. 38
Series
Technical report / Luleå University of Technology, ISSN 1402-1536
National Category
Infrastructure Engineering Other Materials Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-106153 (URN)978-91-8048-597-5 (ISBN)
Projects
Trafikverkets och Anläggning AMAs metoder för undvikande av tidig sprickbildning i betong – nyutveckling med hänsyn till miljökriterier
Available from: 2024-06-10 Created: 2024-06-10 Last updated: 2024-06-10Bibliographically approved
Nilsson, M., Nilimaa, J., Emborg, M., Hösthagen, A. & Westerholm, M. (2024). Spänningsberäkningar, metodik och kriterier. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Spänningsberäkningar, metodik och kriterier
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2024 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2024. p. 30
Series
Technical report / Luleå University of Technology, ISSN 1402-1536
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Building Materials
Identifiers
urn:nbn:se:ltu:diva-108190 (URN)978-91-8048-610-1 (ISBN)
Projects
Trafikverkets och Anläggning AMAs metoder för undvikande av tidig sprickbildning i betong – nyutveckling med hänsyn till miljökriterier
Funder
Swedish Transport Administration, FOI-BBTSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Funder: Heidelberg Materials, Cement och Betong

Available from: 2024-06-28 Created: 2024-06-28 Last updated: 2024-07-02Bibliographically approved
Hösthagen, A. (2017). Thermal Crack Risk Estimation and Material Properties of Young Concrete. (Licentiate dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Thermal Crack Risk Estimation and Material Properties of Young Concrete
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents how to establish a theoretical model to predict risk of thermal cracking in young concrete when cast on ground or an arbitrary construction. The crack risk in young concrete is determined in two steps: 1) calculation of temperature distribution within newly cast concrete and adjacent structure; 2) calculation of stresses caused by thermal and moisture (due to self-desiccation, if drying shrinkage not included) changes in the analyzed structure. If the stress reaches the tensile strength of the young concrete, one or several cracks will occur.

The main focus of this work is how to establish a theoretical model denoted Equivalent Restraint Method model, ERM, and the correlation between ERM models and empirical experiences. A key factor in these kind of calculations is how to model the restraint from any adjacent construction part or adjoining restraining block of any type.

The building of a road tunnel and a railway tunnel has been studied to collect temperature measurements and crack patterns from the first object, and temperature and thermal dilation measurements from the second object, respectively. These measurements and observed cracks were compared to the theoretical calculations to determine the level of agreement between empirical and theoretical results.

Furthermore, this work describes how to obtain a set of fully tested material parameters at CompLAB (test laboratory at Luleå University of Technology, LTU) suitable to be incorporated into the calculation software used. It is of great importance that the obtained material parameters describe the thermal and mechanical properties of the young concrete accurately, in order to perform reliable crack risk calculations.  Therefore, analysis was performed that show how a variation in the evaluated laboratory tests will affect the obtained parameters and what effects it has on calculated thermal stresses.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2017. p. 85
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Thermal cracking risk, young concrete, Equivalent Restraint Method, strength development, heat of hydration, creep, shrinkage, thermal dilation, modeling, field observations
National Category
Construction Management
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-65495 (URN)978-91-7583-951-6 (ISBN)978-91-7583-952-3 (ISBN)
Presentation
2017-10-10, F1031, Luleå, 10:00 (English)
Opponent
Supervisors
Available from: 2017-09-05 Created: 2017-09-05 Last updated: 2018-06-20Bibliographically approved
Hösthagen, A., Jonasson, J.-E., Emborg, M. & Nilsson, M. (2017). Thermal Crack Risk Estimations of Concrete Walls: Temperature and Strain Measurements Correlated to the Equivalent Restraint Method. In: Proceedings of the 23rd Nordic Concrete Research Symposium: . Paper presented at 23th Symposium on Nordic Concrete Research & Developement, Aalborg, Denmark, 21 - 23 August 2017. Oslo, Norway: Nordic Concrete Federation
Open this publication in new window or tab >>Thermal Crack Risk Estimations of Concrete Walls: Temperature and Strain Measurements Correlated to the Equivalent Restraint Method
2017 (English)In: Proceedings of the 23rd Nordic Concrete Research Symposium, Oslo, Norway: Nordic Concrete Federation , 2017Conference paper, Published paper (Refereed)
Abstract [en]

 Self-induced non-elastic deformations in hardening concrete, caused by restrained volume changes due to thermal dilatation and moisture deformations, often leads to cracking. In crack risk analyses, determination of the degree of restraint is vital. One model to estimate the restraint and calculate the thermal crack risk is the Equivalent Restraint Method, ERM. The method has previously been analyzed but needs to be further examined and validated. Recordings of tunnel sections were performed and compared to calculated values by ERM. Satisfying correlation between theoretically estimated and observed temperatures, strains and time of through cracking was achieve which is promising for future implementation and testing of the method.

Place, publisher, year, edition, pages
Oslo, Norway: Nordic Concrete Federation, 2017
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-65990 (URN)978-82-8208-056-9 (ISBN)
Conference
23th Symposium on Nordic Concrete Research & Developement, Aalborg, Denmark, 21 - 23 August 2017
Available from: 2017-10-06 Created: 2017-10-06 Last updated: 2023-09-05Bibliographically approved
Nilimaa, J., Hösthagen, A. & Emborg, M. (2017). Thermal Crack Risk of Concrete Structures: Evaluation of Theoretical Models for Tunnels and Bridges. Nordic Concrete Research, 56(1), 55-69
Open this publication in new window or tab >>Thermal Crack Risk of Concrete Structures: Evaluation of Theoretical Models for Tunnels and Bridges
2017 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 56, no 1, p. 55-69Article in journal (Refereed) Published
Abstract [en]

An approach for thermal crack risk estimations was introduced in the Swedish design guidelines BRO 94. The cracking occurs during the early hardening process because of the exothermic reactions between water and cement and often result in high repair costs and delayed construction. This paper studies and validates the inherent safety levels for one typical case of concrete structure. Three slab-frame structures were analysed and the original crack risk estimations were compared to the actual cracking and postcalculations were carried out, using actual parameters. This paper shows that walls with computed strain ratios over 70% were affected by thermal cracks.

Place, publisher, year, edition, pages
Nordic Concrete Federation, 2017
Keywords
Thermal cracking, Structural Design, Sustainability, Concrete tunnels
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-64967 (URN)000425406000006 ()
Note

Validerad;2017;Nivå 1;2017-08-16 (rokbeg)

Available from: 2017-08-07 Created: 2017-08-07 Last updated: 2018-06-20Bibliographically approved
Hösthagen, A., Jonasson, J.-E., Emborg, M. & Hedlund, H. (2014). Equivalent Restraint Method Correlated to Empirical Measurements (ed.). Paper presented at Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014. Nordic Concrete Research, 50, 505-508
Open this publication in new window or tab >>Equivalent Restraint Method Correlated to Empirical Measurements
2014 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, p. 505-508Article in journal (Refereed) Published
Abstract [en]

The present study deals with the correlation between numerical models and empirical observations in newly cast concrete specimens. The model used is the equivalent restraint method, ERM, which is established from several local restraint method calculations, LRM. The csating of walls in a tunnel construction is investigated. Correlation between models and empirical measurements is established in three steps.

National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-27616 (URN)11cbb2cf-a35e-4581-a829-d06f7ee33a63 (Local ID)11cbb2cf-a35e-4581-a829-d06f7ee33a63 (Archive number)11cbb2cf-a35e-4581-a829-d06f7ee33a63 (OAI)
Conference
Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014
Note
Godkänd; 2014; 20140830 (mem); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-06-20Bibliographically approved
Hösthagen, A., Jonasson, J.-E., Emborg, M., Hedlund, H., Wallin, K. & Stelmarczyk, M. (2014). Thermal crack risk estimations for tunnel: equivalent restraint method correlated to empirical observations (ed.). Nordic Concrete Research, 49, 127-143
Open this publication in new window or tab >>Thermal crack risk estimations for tunnel: equivalent restraint method correlated to empirical observations
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2014 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 49, p. 127-143Article in journal (Refereed) Published
Abstract [en]

The present study deals with the correlation between numerical models and empirical observations in newly cast concrete structures. The model used is the equivalent restraint method, ERM, which is established from several local restraint method calculations, LRM. The casting of walls and roof in a tunnel construction is investigated. Correlation between models and empirical measurements is established in three steps: 1) the restraint situation is analyzed; 2) the calculated temperature developments are compared to empirical temperature measurements to calibrate the models; and 3) calculated strain ratios are compared with observed crack patterns, and in general a good correlation is achieved

National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-7912 (URN)656313e5-0089-473b-bb5e-b64a2948f62c (Local ID)656313e5-0089-473b-bb5e-b64a2948f62c (Archive number)656313e5-0089-473b-bb5e-b64a2948f62c (OAI)
Note

Validerad; 2014; 20140829 (mem)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2023-09-08Bibliographically approved
Al-Gburi, M., Jonasson, J.-E., Nilsson, M., Hedlund, H. & Hösthagen, A. (2012). Simplified methods for crack risk analyses of early age concrete: Part 1: Development of Equivalent Restraint Method (ed.). Nordic Concrete Research, 46(2), 17-38
Open this publication in new window or tab >>Simplified methods for crack risk analyses of early age concrete: Part 1: Development of Equivalent Restraint Method
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2012 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 46, no 2, p. 17-38Article in journal (Refereed) Published
Abstract [en]

The present study deals with both the compensation plane method, CPM, and local restraint method, LRM, as alternative methods studying crack risks for early age concrete. It is shown that CPM can be used both for cooling and heating, but basic LRM cannot be applied to heating. This paper presents an improved equivalent restraint method, ERM, which easily can be applied both for usage of heating and cooling for general structures. Restraint curves are given for two different infrastructures, one founded on frictional materials and another on rock. Such curves might be directly applied in design using LRM and ERM.

Keywords
Local restraint methods, compensation plane method, equivalent restraint method, crack risk, early age concrete
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-2677 (URN)054cb94e-1242-4a88-9ab4-29c8bc31a326 (Local ID)054cb94e-1242-4a88-9ab4-29c8bc31a326 (Archive number)054cb94e-1242-4a88-9ab4-29c8bc31a326 (OAI)
Note

Validerad; 2012; 20121210 (majali)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2023-09-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9386-3718

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