Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete
Previous literature indicates a decrease in the mechanical properties of various concrete types that contain recycled aggregates (RA), due to their porosity and to their interface of transition zone (ITZ). However, other components of the RA concrete microstructure have not yet been explored, such a...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-05-01
|
| Series: | Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1944/13/9/2114 |
| _version_ | 1797568925484974080 |
|---|---|
| author | Kheira Zitouni Assia Djerbi Abdelkader Mebrouki |
| author_facet | Kheira Zitouni Assia Djerbi Abdelkader Mebrouki |
| author_sort | Kheira Zitouni |
| collection | DOAJ |
| description | Previous literature indicates a decrease in the mechanical properties of various concrete types that contain recycled aggregates (RA), due to their porosity and to their interface of transition zone (ITZ). However, other components of the RA concrete microstructure have not yet been explored, such as the modification of the new paste (NP) with respect to a reference concrete. This paper deals with the microstructure of the new paste of self-compacting concrete (SCC) for different levels of RA. The water to binder ratio (w/b) was kept constant for all concrete mixtures, and equal to 0.5. The SCC mixtures were prepared with percentages of coarse RA of 0%, 30%, 50% and 100%. Mercury intrusion porosimetry test (MIP) and scanning electron microscope (SEM) observations were conducted on the new paste of each concrete. The results indicated that the porosity of the new paste presents a significant variation for replacement percentages of 50% and 100% with respect to NP0 and NP30. However, RA contributed to the refinement of the pore structure of the new paste. The amount of macrospores the diameter of which is in the 50–10,000 nm range was reduced to 20% for NP50 and NP100, while it was about 30% for NP0 and NP30, attributed to the water released by RA. Compressive strength loss for SCC50 and SCC100 concretes are both influenced by porosity of RA, and by the NP porosity. The latter is similar for these two concretes with the 26% increase compared to a reference concrete. |
| first_indexed | 2024-03-10T20:04:49Z |
| format | Article |
| id | doaj.art-bed3d9f150fc4146ab566af8feececf8 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T20:04:49Z |
| publishDate | 2020-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-bed3d9f150fc4146ab566af8feececf82023-11-19T23:22:05ZengMDPI AGMaterials1996-19442020-05-01139211410.3390/ma13092114Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting ConcreteKheira Zitouni0Assia Djerbi1Abdelkader Mebrouki2Civil Engineering and Architecture Department-LCTPE, Faculty of Sciences and Technology, Abdelhamid Ibn-Badis University, 27000 Mostaganem, AlgeriaMAST Department-FM2D, University Gustave Eiffel, IFSTTAR, F-77447 Marne la Vallée, FranceCivil Engineering and Architecture Department-LCTPE, Faculty of Sciences and Technology, Abdelhamid Ibn-Badis University, 27000 Mostaganem, AlgeriaPrevious literature indicates a decrease in the mechanical properties of various concrete types that contain recycled aggregates (RA), due to their porosity and to their interface of transition zone (ITZ). However, other components of the RA concrete microstructure have not yet been explored, such as the modification of the new paste (NP) with respect to a reference concrete. This paper deals with the microstructure of the new paste of self-compacting concrete (SCC) for different levels of RA. The water to binder ratio (w/b) was kept constant for all concrete mixtures, and equal to 0.5. The SCC mixtures were prepared with percentages of coarse RA of 0%, 30%, 50% and 100%. Mercury intrusion porosimetry test (MIP) and scanning electron microscope (SEM) observations were conducted on the new paste of each concrete. The results indicated that the porosity of the new paste presents a significant variation for replacement percentages of 50% and 100% with respect to NP0 and NP30. However, RA contributed to the refinement of the pore structure of the new paste. The amount of macrospores the diameter of which is in the 50–10,000 nm range was reduced to 20% for NP50 and NP100, while it was about 30% for NP0 and NP30, attributed to the water released by RA. Compressive strength loss for SCC50 and SCC100 concretes are both influenced by porosity of RA, and by the NP porosity. The latter is similar for these two concretes with the 26% increase compared to a reference concrete.https://www.mdpi.com/1996-1944/13/9/2114recycled aggregateself-compacting concretemercury intrusion porosimetrySEM observationnew pastecompressive strength |
| spellingShingle | Kheira Zitouni Assia Djerbi Abdelkader Mebrouki Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete Materials recycled aggregate self-compacting concrete mercury intrusion porosimetry SEM observation new paste compressive strength |
| title | Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete |
| title_full | Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete |
| title_fullStr | Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete |
| title_full_unstemmed | Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete |
| title_short | Study on the Microstructure of the New Paste of Recycled Aggregate Self-Compacting Concrete |
| title_sort | study on the microstructure of the new paste of recycled aggregate self compacting concrete |
| topic | recycled aggregate self-compacting concrete mercury intrusion porosimetry SEM observation new paste compressive strength |
| url | https://www.mdpi.com/1996-1944/13/9/2114 |
| work_keys_str_mv | AT kheirazitouni studyonthemicrostructureofthenewpasteofrecycledaggregateselfcompactingconcrete AT assiadjerbi studyonthemicrostructureofthenewpasteofrecycledaggregateselfcompactingconcrete AT abdelkadermebrouki studyonthemicrostructureofthenewpasteofrecycledaggregateselfcompactingconcrete |