Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete
Self-compacting concrete (SCC) should generally be placed continuously, but it is not uncommon for contractors to be forced to use interruptions in concrete works due to delivery delays. The multilayer casting of SCC can cause weak bond conditions in the contact area of subsequent layers. Methods of...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/13/15/3330 |
| _version_ | 1797561263923920896 |
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| author | Piotr Dybeł Milena Kucharska |
| author_facet | Piotr Dybeł Milena Kucharska |
| author_sort | Piotr Dybeł |
| collection | DOAJ |
| description | Self-compacting concrete (SCC) should generally be placed continuously, but it is not uncommon for contractors to be forced to use interruptions in concrete works due to delivery delays. The multilayer casting of SCC can cause weak bond conditions in the contact area of subsequent layers. Methods of preventing cold joint or lift line formation for normal concretes are not suitable for self-compacting concretes. This article provides research on the effect of multilayer casting technology on the bond strength between two layers of SCC. Three technological variants of connecting successive layers of SCC mixture on beam elements were analyzed: The free flow of the mixture, dropping the mixture from a greater height, and mechanical disturbance of the first layer. Three delay times were applied: 30, 45, and 60 min between two layers of SCC. In general, the research revealed that, regardless of the multilayer casting variant, the bond strength between two layers decreased as the delay time was extended. The best performance and the lowest drop in bond strength were obtained for samples with a mechanically disturbed first layer, independent of the delay time. This method gave similar results to a reference element made without a break in concreting. It was also demonstrated that current recommendations and standard guidelines for multilayer casting appear to be insufficient for ensuring an adequate bond between layers. |
| first_indexed | 2024-03-10T18:11:33Z |
| format | Article |
| id | doaj.art-ea50ef45f1374767bfa3117855e0d640 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T18:11:33Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-ea50ef45f1374767bfa3117855e0d6402023-11-20T08:04:47ZengMDPI AGMaterials1996-19442020-07-011315333010.3390/ma13153330Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting ConcretePiotr Dybeł0Milena Kucharska1Department of Geomechanics, Civil Engineering and Geotechnics, AGH University of Science and Technology, 30-059 Cracow, PolandDepartment of Geomechanics, Civil Engineering and Geotechnics, AGH University of Science and Technology, 30-059 Cracow, PolandSelf-compacting concrete (SCC) should generally be placed continuously, but it is not uncommon for contractors to be forced to use interruptions in concrete works due to delivery delays. The multilayer casting of SCC can cause weak bond conditions in the contact area of subsequent layers. Methods of preventing cold joint or lift line formation for normal concretes are not suitable for self-compacting concretes. This article provides research on the effect of multilayer casting technology on the bond strength between two layers of SCC. Three technological variants of connecting successive layers of SCC mixture on beam elements were analyzed: The free flow of the mixture, dropping the mixture from a greater height, and mechanical disturbance of the first layer. Three delay times were applied: 30, 45, and 60 min between two layers of SCC. In general, the research revealed that, regardless of the multilayer casting variant, the bond strength between two layers decreased as the delay time was extended. The best performance and the lowest drop in bond strength were obtained for samples with a mechanically disturbed first layer, independent of the delay time. This method gave similar results to a reference element made without a break in concreting. It was also demonstrated that current recommendations and standard guidelines for multilayer casting appear to be insufficient for ensuring an adequate bond between layers.https://www.mdpi.com/1996-1944/13/15/3330multilayer castingself-compacting concretebond strengthlift lineplacement technology |
| spellingShingle | Piotr Dybeł Milena Kucharska Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete Materials multilayer casting self-compacting concrete bond strength lift line placement technology |
| title | Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete |
| title_full | Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete |
| title_fullStr | Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete |
| title_full_unstemmed | Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete |
| title_short | Effect of Placement Technology on the Bond Strength Between Two Layers of Self-Compacting Concrete |
| title_sort | effect of placement technology on the bond strength between two layers of self compacting concrete |
| topic | multilayer casting self-compacting concrete bond strength lift line placement technology |
| url | https://www.mdpi.com/1996-1944/13/15/3330 |
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