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Publications (10 of 57) Show all publications
Min, X., Zhang, J., Tu, Y., Li, X., Wang, C., Sas, G. & Elfgren, L. (2024). A full-range fatigue life prediction model for RC beams strengthened with prestressed CFRP plates accounting for the impact of FRP debonding. Engineering structures, 301, Article ID 117305.
Open this publication in new window or tab >>A full-range fatigue life prediction model for RC beams strengthened with prestressed CFRP plates accounting for the impact of FRP debonding
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2024 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 301, article id 117305Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2024
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-103512 (URN)10.1016/j.engstruct.2023.117305 (DOI)2-s2.0-85179467577 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-01-19 (signyg)

Funder: Natural Science Foundation of Jiangsu Province of China (grant nos. BK20230703); the Scientific Research Foundation of Nanjing Institute of Technology (grant nos. YKJ202122); the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (23KJB560010); National Key Research and Development Program of China (grant nos. 2017YFC0703006-01); Array (2017YFC0703006-01)

Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-02-01Bibliographically approved
Fang, M., Wang, T., Guo, T., Shi, P., Jiang, B., Wang, C., . . . Elfgren, L. (2024). Compressive reactive molecular dynamics on mechanical and structural behaviors of geopolymers: Imposing lateral constraints and varied temperatures. Applied Clay Science, 249, Article ID 107257.
Open this publication in new window or tab >>Compressive reactive molecular dynamics on mechanical and structural behaviors of geopolymers: Imposing lateral constraints and varied temperatures
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2024 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 249, article id 107257Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier Ltd, 2024
National Category
Other Materials Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-103908 (URN)10.1016/j.clay.2024.107257 (DOI)2-s2.0-85182403837 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-16 (joosat);

Funder: National Natural Science Foundation of China (51378104, U23A20661); Jiangsu Province (BZ2021011); Fundamental Research Funds for the Central Universities (2242022k30030, 2242022k30031); National Science Fund for Distinguished Young Scholars (52125802);

Available from: 2024-01-24 Created: 2024-01-24 Last updated: 2024-02-16Bibliographically approved
Wang, T., Cao, J., Guo, T., Tu, Y., Wang, C., Sas, G. & Elfgren, L. (2024). The role of deep learning in reducing computational cost when simulating chloride ion attack on hydrated calcium silicate with molecular dynamics. Construction and Building Materials, 417, Article ID 135257.
Open this publication in new window or tab >>The role of deep learning in reducing computational cost when simulating chloride ion attack on hydrated calcium silicate with molecular dynamics
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2024 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 417, article id 135257Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier Ltd, 2024
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-104320 (URN)10.1016/j.conbuildmat.2024.135257 (DOI)2-s2.0-85184522280 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-20 (joosat);

Funder: Natural Science Foundation of China [grant numbers 51378104]; National Science Fund for Distinguished Young Scholars [grant numbers 52125802]; "One belt, one road" innovation cooperation project, Jiangsu Province [grant numbers BZ2021011]; Fundamental Research Funds for the Central Universities [grant numbers 2242022k30030, 2242022k30031];

Available from: 2024-02-20 Created: 2024-02-20 Last updated: 2024-02-20Bibliographically approved
Min, X., Zhang, J., Li, X., Wang, C., Tu, Y., Sas, G. & Elfgren, L. (2023). A nonlinear prediction model of the debonding process of an FRP-concrete interface under fatigue loading. Construction and Building Materials, 369, Article ID 130583.
Open this publication in new window or tab >>A nonlinear prediction model of the debonding process of an FRP-concrete interface under fatigue loading
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2023 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 369, article id 130583Article in journal (Refereed) Published
Abstract [en]

Externally bonded Fiber Reinforced Polymer (FRP) strengthening has been proven to be an efficient and reliable method for structural strengthening of reinforced concrete (RC) members. However, the beneficial effects of this method can be diminished due to the debonding of the FRP laminates. The mechanism of FRP debonding still requires further research, especially for strengthened members under fatigue loading. To understand and predict the FRP fatigue debonding process better, eleven FRP-concrete joint specimens were tested under static or fatigue loading. Both the theoretical derivation and the experimental study indicated that the debonding growth rate of the FRP laminate depended not only on the mean level (), but also the amplitude () of the applied fatigue load. In addition, the debonded portion of the FRP laminate had a significant impact on the following debonding process due to the friction and mechanical interaction between the debonded FRP and the concrete surface. Therefore, a new nonlinear prediction model is proposed in this paper. The proposed model explicitly took into account the amplitude and the mean level of the fatigue loading, which enabled the effect of both to be modelled. Meanwhile, a correction term was also introduced into the model to account for the influence of the previously debonded FRP laminate. The predicted results of the debonding growth rate and the debonding length agreed well with the experimental results.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Concrete, Debond, Fatigue, Fiber Reinforced Polymer, Interface
National Category
Composite Science and Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-95675 (URN)10.1016/j.conbuildmat.2023.130583 (DOI)000946205000001 ()2-s2.0-85147606490 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-02-21 (joosat);

Funder: Scientific Research Foundation of Nanjing Institute of Technology (YKJ202122); National Key Research and Development Program of China (No. 2017YFC0703006-01)

Available from: 2023-02-21 Created: 2023-02-21 Last updated: 2023-04-21Bibliographically approved
Liu, D., Wang, C., Gonzalez-Libreros, J., Guo, T., Cao, J., Tu, Y., . . . Sas, G. (2023). A review of concrete properties under the combined effect of fatigue and corrosion from a material perspective. Construction and Building Materials, 369, Article ID 130489.
Open this publication in new window or tab >>A review of concrete properties under the combined effect of fatigue and corrosion from a material perspective
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2023 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 369, article id 130489Article, review/survey (Refereed) Published
Abstract [en]

When in use, reinforced concrete bridge structures not only experience high-frequency fatigue loading caused by passing vehicles, but also suffer from the effects of a corrosive environment. In addition to fatigue damage to reinforcement, long-term fatigue loading also causes concrete cracking and deterioration of pore structures, thereby accelerating the ingress of external corrosive substances and reducing concrete durability. Long-term exposure to a corrosive environment also reduces the performance of concrete and causes corrosion of reinforcement materials, affecting the fatigue performance of the structure. Therefore, there is a combined effect between fatigue loads and corrosion on concrete. This paper is a review of the current literature from a material perspective on the performance degradation of concrete under the combined action of fatigue loading and corrosion, that is, carbonation, chloride ion attack, freeze–thaw cycles, and sulphate attack. The paper includes (1) a description of a test method for examining the combined action of fatigue loading and corrosion, (2) a summary of performance degradation of concrete under the combined effect of fatigue loading and corrosion, and (3) an introduction to durability deterioration models considering fatigue damage, and fatigue models that can account for corrosion. Finally, potential future research on concrete under the combined effect of fatigue loading and corrosion is described.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Concrete, Fatigue load, Corrosion, Combined action, Carbonation, Chloride attack, Freeze–thaw cycles, Sulphate attack, Deterioration, Modelling
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-95539 (URN)10.1016/j.conbuildmat.2023.130489 (DOI)000927776800001 ()2-s2.0-85147195723 (Scopus ID)
Funder
Swedish Transport Administration
Note

Validerad;2023;Nivå 2;2023-02-08 (hanlid);

Funder: FOI-BBT program (BBT-2019-022)

Available from: 2023-02-08 Created: 2023-02-08 Last updated: 2023-04-21Bibliographically approved
Liu, D., Wang, C., Gonzalez-Libreros, J., Tu, Y., Elfgren, L. & Sas, G. (2023). A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass. Journal of Wind Engineering and Industrial Aerodynamics, 239, Article ID 105458.
Open this publication in new window or tab >>A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass
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2023 (English)In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 239, article id 105458Article in journal (Refereed) Published
Abstract [en]

Noise barriers need to be installed along high-speed railway lines to protect nearby inhabitants from the noise pollution caused by the running of high-speed trains (HSTs). The vertical noise barrier is the main structural type. However, when an HST passes through the noise barriers sited along the track, significant and transient aerodynamic pressure will act on the surface of the noise barriers, resulting in strong dynamic responses and even fatigue damage. Therefore, it is important to determine the train-induced aerodynamic load on the barrier surface and analyze the dynamic behaviors of the noise barriers under such a load for its structural design and to guarantee its safety and durability. This paper is a systematic review of the current literature on the aerodynamic load and dynamic behavior of vertical noise barriers; it includes (1) a summary and analysis of characteristics of such aerodynamic pressure and relevant influencing factors, (2) an introduction to measurement methods of aerodynamic load and relevant pressure models on the surface of noise barriers, and (3) a description of the dynamic response and fatigue analysis of noise barriers under such loads. Finally, potential further studies on this topic are discussed, and conclusions are drawn.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Noise barrier, Railway, High-speed train, Aerodynamic load, Dynamic response, Fatigue
National Category
Vehicle Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-98162 (URN)10.1016/j.jweia.2023.105458 (DOI)2-s2.0-85160798389 (Scopus ID)
Funder
Swedish Transport Administration, “Excellence Area 4” and FOI-BBT program (grant number BBT-2019-022)
Note

Validerad;2023;Nivå 2;2023-06-12 (joosat);

Licens fulltext: CC BY License

Available from: 2023-06-12 Created: 2023-06-12 Last updated: 2023-10-12Bibliographically approved
Cao, J., Wang, C., Wang, T., Gonzalez-Libreros, J., Tu, Y., Sas, G. & Elfgren, L. (2023). Effects of Temperature and NaCl Concentration on the Adsorption of C-S-H Gel in Cement Paste: A Multi-fidelity Molecular Dynamics Simulation. In: Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt (Ed.), Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2: . Paper presented at International Symposium of the International Federation for Structural Concrete, fib Symposium 2023, Istanbul, Turkey, June 5-7, 2023 (pp. 499-508). Springer, 2
Open this publication in new window or tab >>Effects of Temperature and NaCl Concentration on the Adsorption of C-S-H Gel in Cement Paste: A Multi-fidelity Molecular Dynamics Simulation
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2023 (English)In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 499-508Conference paper, Published paper (Refereed)
Abstract [en]

The durability and compressive strength of concrete will vary with the material components, ambient temperature, external intrusion. Using molecular dynamics (MD) methods to study the dynamic behavior of particles in cement-based materials can help us understand the underlying mechanism of property changes in concrete caused by above factors at the atomic level. So far, MD methods have been widely used to analyze the physical and chemical properties of concrete materials and the interaction mechanism between different interfaces at the nanoscale. However, too much complexity in the models will reduce the result accuracy and increase the computational cost. A suitable neural network structure can not only ensure the accuracy of analysis results, but also reduce the computational cost. In this work, MD methods are applied to build the models to explore the diffusivity of Na+ and Cl− in the calcium silicate hydrate (C-S-H) gel pores at different concentration and temperatures. In the process of running models, part of the MD models’ fidelity is reduced to save the computational cost, then the trained multi-fidelity physics informed neural network framework was used to obtain more accurate analysis results. The combination of MD simulations and deep learning methods expands the application range of MD in the field of concrete structure, has good development prospect and application value.

Place, publisher, year, edition, pages
Springer, 2023
Series
Lecture Notes in Civil Engineering, ISSN 2366-2557, E-ISSN 2366-2565 ; 350
Keywords
Multi-fidelity Model, Molecular Dynamics, C-S-H Gel, Ion diffusion
National Category
Construction Management
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-99604 (URN)10.1007/978-3-031-32511-3_53 (DOI)2-s2.0-85164267102 (Scopus ID)978-3-031-32510-6 (ISBN)978-3-031-32511-3 (ISBN)
Conference
International Symposium of the International Federation for Structural Concrete, fib Symposium 2023, Istanbul, Turkey, June 5-7, 2023
Available from: 2023-08-14 Created: 2023-08-14 Last updated: 2023-08-14Bibliographically approved
Cao, J., Kong, L., Guo, T., Shi, P., Wang, C., Tu, Y., . . . Elfgren, L. (2023). Molecular dynamics simulations of ion migration and adsorption on the surfaces of AFm hydrates. Applied Surface Science, 615, Article ID 156390.
Open this publication in new window or tab >>Molecular dynamics simulations of ion migration and adsorption on the surfaces of AFm hydrates
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2023 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 615, article id 156390Article in journal (Refereed) Published
Abstract [en]

Chloride salts can cause severe corrosion damage to reinforcing steel bars in cement-based materials whereas nitrite salts inhibit corrosion. The storage and release of these two anions in cement materials occurs mainly at the interface of monosulfoaluminate (AFm) hydrates. In this paper, molecular dynamics are used to analyze the interaction between anions and AFm phases and clarify the competitive relationships between the anions at adsorption sites on the AFm surface. It was found that the ordered structure of the [Ca2Al(OH)6]+ layers of the AFm plays a key role in anion adsorption and that the mobility of ions desorbed from AFm layers decreases linearly with increasing proximity to the AFm surfaces.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Interface interaction, Ion corrosion, Ion mobility, Molecular dynamics, Monosulfoaluminate hydrate
National Category
Physical Chemistry
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-95563 (URN)10.1016/j.apsusc.2023.156390 (DOI)000963225500001 ()2-s2.0-85146673191 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-02-10 (hanlid);

Funder: National Natural Science Foundation of China (51378104); Jiangsu Province (BZ2021011)

Available from: 2023-02-10 Created: 2023-02-10 Last updated: 2023-04-21Bibliographically approved
Wen, R., Tu, Y., Guo, T., Yu, Q., Shi, P., Ji, Y., . . . Elfgren, L. (2023). Molecular dynamics study on coupled ion transport in aluminium-doped cement-based materials: Effect of concentration. Advances in Cement Research, 35(2), 81-95
Open this publication in new window or tab >>Molecular dynamics study on coupled ion transport in aluminium-doped cement-based materials: Effect of concentration
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2023 (English)In: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 35, no 2, p. 81-95Article in journal (Refereed) Published
Abstract [en]

The mutual inhibition effect of transport of sulphate and chloride in concrete specimen was determined in a macroscopic experiment. Higher concentration of sulphate has a better inhibition effect on chloride transport and the opposite is also true. In this paper, molecular dynamics (MD) simulation was performed to explore the effect of concentration (0, 0.5, 1.0 mol/L) on the transport of mixed solutions (NaCl and Na2SO4) in the main hydration products of aluminium-doped cement-based materials (i.e., calcium-aluminium-silicate-hydrate (C-A-S-H) gel). Sulphate was found to promote the aggregation of other ions to form ion clusters, which can reduce the effective width of the channel entrance and create a “necking” effect, thus reducing the overall transport rate of the solution. With the increase of NaCl concentration, sulphate ions in the mixed solution can adsorb more Na+ and Cl+ ions, and then form larger ion clusters to block the nanopores. Moreover, with increasing Na2SO4 concentration, higher amount of sulphate ions existing in the solution makes it possible to form more ion clusters. The results can provide a reasonable nanoscale explanation for macroscopic experiment.

Place, publisher, year, edition, pages
ICE Publishing, 2023
Keywords
Aluminates, Cement/cementitious materials, Durability, Nanostructure
National Category
Materials Chemistry
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-92078 (URN)10.1680/jadcr.22.00028 (DOI)000836589300001 ()2-s2.0-85133177490 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-04-18 (joosat);

Available from: 2022-07-06 Created: 2022-07-06 Last updated: 2023-04-18Bibliographically approved
Wang, T., Tu, Y., Guo, T., Fang, M., Shi, P., Yuan, L., . . . Elfgren, L. (2023). Molecular dynamics study on structural characteristics and mechanical properties of sodium aluminosilicate hydrate with immobilized radioactive Cs and Sr ions. Applied Clay Science, 243, Article ID 107042.
Open this publication in new window or tab >>Molecular dynamics study on structural characteristics and mechanical properties of sodium aluminosilicate hydrate with immobilized radioactive Cs and Sr ions
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2023 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 243, article id 107042Article in journal (Refereed) Published
Abstract [en]

As a low-carbon, environment-friendly and economical resource for nuclear power generation, radionuclide emission and storage has received worldwide attention. Geopolymer concrete is a green and sustainable building material that can be used to immobilize radionuclides. In the present study, molecular dynamics simulations were conducted to investigate the structural and mechanical properties of sodium aluminosilicate hydrate (NASH) gel, the main component of geopolymer concrete, with/without immobilized radioactive Cs and Sr ions. The three-dimensional structure of NASH gel enabled good immobilization of both radioactive Cs and Sr ions owing to the large radius of Cs ions and high charge density of Sr ions. Addition of Cs ions reduced the strength of the gel and increased the fracture strain, whereas addition of Sr ions increased the strength and significantly increased the ductility. Addition of Sr ions increased the number of penta-coordinated Al in the structure. Consequently, breakage of these bonds required more energy to be absorbed from outside. The nanoscale molecular dynamics simulations provided a theoretical support at atomic level for understanding the structural and mechanical characteristics of geopolymers pertinent to the immobilization of nuclear waste.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Geopolymer, Mechanical properties, Molecular dynamics, NASH gel, Nuclear waste
National Category
Other Materials Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-99432 (URN)10.1016/j.clay.2023.107042 (DOI)2-s2.0-85164669652 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-08-10 (joosat);

Funder: Natural Science Foundation of China (grant no. 51378104); National Science Fund for Distinguished Young Scholars (grant no. 52125802); Jiangsu Province (grant no. BZ2021011); Fundamental Research Funds for the Central Universities (2242022k30030, 2242022k30031)

Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2023-08-10Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-8372-1967

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