Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength
Recycled concrete, i.e., concrete which contains aggregates that are obtained from crushing waste concrete, typically exhibits a smaller strength than conventional concretes. We herein decipher the origin and quantify the extent of the strength reduction by means of multiscale micromechanics-based m...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-06-01
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| Series: | Applied Sciences |
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| Online Access: | http://www.mdpi.com/2076-3417/8/6/976 |
| _version_ | 1830162270747885568 |
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| author | Markus Königsberger Stéphanie Staquet |
| author_facet | Markus Königsberger Stéphanie Staquet |
| author_sort | Markus Königsberger |
| collection | DOAJ |
| description | Recycled concrete, i.e., concrete which contains aggregates that are obtained from crushing waste concrete, typically exhibits a smaller strength than conventional concretes. We herein decipher the origin and quantify the extent of the strength reduction by means of multiscale micromechanics-based modeling. Therefore, the microstructure of recycled concrete is represented across four observation scales, spanning from the micrometer-sized scale of cement hydration products to the centimeter-sized scale of concrete. Recycled aggregates are divided into three classes with distinct morphological features: plain aggregates which are clean of old cement paste, mortar aggregates, and aggregates covered by old cement paste. Macroscopic loading is concentrated via interfacial transition zones (ITZs)—which occur mutually between aggregates, old, and new cement paste—to the micrometer-sized hydrates resolved at the smallest observation scale. Hydrate failure within the most unfavorably loaded ITZ is considered to trigger concrete failure. Modeling results show that failure in either of the ITZs might be critical, and that the failure mode is governed by the mutual stiffness contrast between aggregates, old, and new paste, which depend, in turn, on the concrete composition and on the material’s maturity. The model predicts that the strength difference between recycled concrete and conventional concrete is less pronounced (i) at an early age compared to mature ages, (ii) when the old cement paste content is small, and (iii) when recycling a high-quality parent concrete. |
| first_indexed | 2024-12-17T15:17:10Z |
| format | Article |
| id | doaj.art-95a5ca5909d141b5bd007417ba2d2868 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-12-17T15:17:10Z |
| publishDate | 2018-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-95a5ca5909d141b5bd007417ba2d28682022-12-21T21:43:30ZengMDPI AGApplied Sciences2076-34172018-06-018697610.3390/app8060976app8060976Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material StrengthMarkus Königsberger0Stéphanie Staquet1BATir Department, ULB—Université libre de Bruxelles, CP194/4, 87 Avenue A. Buyl, 1050 Brussels, BelgiumBATir Department, ULB—Université libre de Bruxelles, CP194/4, 87 Avenue A. Buyl, 1050 Brussels, BelgiumRecycled concrete, i.e., concrete which contains aggregates that are obtained from crushing waste concrete, typically exhibits a smaller strength than conventional concretes. We herein decipher the origin and quantify the extent of the strength reduction by means of multiscale micromechanics-based modeling. Therefore, the microstructure of recycled concrete is represented across four observation scales, spanning from the micrometer-sized scale of cement hydration products to the centimeter-sized scale of concrete. Recycled aggregates are divided into three classes with distinct morphological features: plain aggregates which are clean of old cement paste, mortar aggregates, and aggregates covered by old cement paste. Macroscopic loading is concentrated via interfacial transition zones (ITZs)—which occur mutually between aggregates, old, and new cement paste—to the micrometer-sized hydrates resolved at the smallest observation scale. Hydrate failure within the most unfavorably loaded ITZ is considered to trigger concrete failure. Modeling results show that failure in either of the ITZs might be critical, and that the failure mode is governed by the mutual stiffness contrast between aggregates, old, and new paste, which depend, in turn, on the concrete composition and on the material’s maturity. The model predicts that the strength difference between recycled concrete and conventional concrete is less pronounced (i) at an early age compared to mature ages, (ii) when the old cement paste content is small, and (iii) when recycling a high-quality parent concrete.http://www.mdpi.com/2076-3417/8/6/976recycled concreterecycled aggregatesinterfacial transition zonemultiscalemicromechanicsfailurecompressive strength |
| spellingShingle | Markus Königsberger Stéphanie Staquet Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength Applied Sciences recycled concrete recycled aggregates interfacial transition zone multiscale micromechanics failure compressive strength |
| title | Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength |
| title_full | Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength |
| title_fullStr | Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength |
| title_full_unstemmed | Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength |
| title_short | Micromechanical Multiscale Modeling of ITZ-Driven Failure of Recycled Concrete: Effects of Composition and Maturity on the Material Strength |
| title_sort | micromechanical multiscale modeling of itz driven failure of recycled concrete effects of composition and maturity on the material strength |
| topic | recycled concrete recycled aggregates interfacial transition zone multiscale micromechanics failure compressive strength |
| url | http://www.mdpi.com/2076-3417/8/6/976 |
| work_keys_str_mv | AT markuskonigsberger micromechanicalmultiscalemodelingofitzdrivenfailureofrecycledconcreteeffectsofcompositionandmaturityonthematerialstrength AT stephaniestaquet micromechanicalmultiscalemodelingofitzdrivenfailureofrecycledconcreteeffectsofcompositionandmaturityonthematerialstrength |