Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete
In view of the growing demand for sustainable and lightweight concrete structures, the use of ultra-high-performance concrete (UHPC) is becoming increasingly important. However, fatigue loads occur more frequently in nature than static loads. Despite the impressive mechanical properties of UHPC, a r...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-10-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/14/21/6337 |
| _version_ | 1797512206019985408 |
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| author | Sebastian Rybczynski Gunnar Schaan Maksym Dosta Martin Ritter Frank Schmidt-Döhl |
| author_facet | Sebastian Rybczynski Gunnar Schaan Maksym Dosta Martin Ritter Frank Schmidt-Döhl |
| author_sort | Sebastian Rybczynski |
| collection | DOAJ |
| description | In view of the growing demand for sustainable and lightweight concrete structures, the use of ultra-high-performance concrete (UHPC) is becoming increasingly important. However, fatigue loads occur more frequently in nature than static loads. Despite the impressive mechanical properties of UHPC, a reduced tolerance for cyclic loading is known. For this reason, our paper deals with experimental and numerical investigations regarding the main causes for crack initiation on the meso, micro, and nanoscale. After mechanical fatigue tests, we use both scanning (SEM) and transmission electron microscopy (TEM) to characterize microstructural changes. A new rheological model was developed to apply those changes to the mesoscopic scale. The origins of fatigue damaging can be traced back to a transformation of nanoscale ettringite, resulting in a densification of the surrounding binder matrix. Additionally, a higher content of unhydrated cement clinker in the matrix benefits fatigue resistance. On the mesoscale, stress peaks around aggregate grains expand into the surrounding binder with increasing load cycles and lead to higher degradation. |
| first_indexed | 2024-03-10T05:58:34Z |
| format | Article |
| id | doaj.art-31bea7ec6fdf4fe4bf281dd318dfe6c3 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T05:58:34Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-31bea7ec6fdf4fe4bf281dd318dfe6c32023-11-22T21:10:37ZengMDPI AGMaterials1996-19442021-10-011421633710.3390/ma14216337Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance ConcreteSebastian Rybczynski0Gunnar Schaan1Maksym Dosta2Martin Ritter3Frank Schmidt-Döhl4Institute of Materials, Physics and Chemistry of Buildings, Hamburg University of Technology, 21073 Hamburg, GermanyInstitute of Materials, Physics and Chemistry of Buildings, Hamburg University of Technology, 21073 Hamburg, GermanyInstitute of Solids Process Engineering and Particle Technology, Hamburg University of Technology, 21073 Hamburg, GermanyElectron Microscopy Unit, Hamburg University of Technology, 21073 Hamburg, GermanyInstitute of Materials, Physics and Chemistry of Buildings, Hamburg University of Technology, 21073 Hamburg, GermanyIn view of the growing demand for sustainable and lightweight concrete structures, the use of ultra-high-performance concrete (UHPC) is becoming increasingly important. However, fatigue loads occur more frequently in nature than static loads. Despite the impressive mechanical properties of UHPC, a reduced tolerance for cyclic loading is known. For this reason, our paper deals with experimental and numerical investigations regarding the main causes for crack initiation on the meso, micro, and nanoscale. After mechanical fatigue tests, we use both scanning (SEM) and transmission electron microscopy (TEM) to characterize microstructural changes. A new rheological model was developed to apply those changes to the mesoscopic scale. The origins of fatigue damaging can be traced back to a transformation of nanoscale ettringite, resulting in a densification of the surrounding binder matrix. Additionally, a higher content of unhydrated cement clinker in the matrix benefits fatigue resistance. On the mesoscale, stress peaks around aggregate grains expand into the surrounding binder with increasing load cycles and lead to higher degradation.https://www.mdpi.com/1996-1944/14/21/6337ultra-high-performance concretefatigueelectron microscopyettringite transformationbonded particle modeldiscrete element method |
| spellingShingle | Sebastian Rybczynski Gunnar Schaan Maksym Dosta Martin Ritter Frank Schmidt-Döhl Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete Materials ultra-high-performance concrete fatigue electron microscopy ettringite transformation bonded particle model discrete element method |
| title | Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete |
| title_full | Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete |
| title_fullStr | Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete |
| title_full_unstemmed | Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete |
| title_short | Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete |
| title_sort | discrete element modeling and electron microscopy investigation of fatigue induced microstructural changes in ultra high performance concrete |
| topic | ultra-high-performance concrete fatigue electron microscopy ettringite transformation bonded particle model discrete element method |
| url | https://www.mdpi.com/1996-1944/14/21/6337 |
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