Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair

3D concrete printing can be used to automatically repair concrete structures, while the practical application is still hindered due to the lack of interfacial bonding. A concept using a chemically reactive coating at the interface is proposed to overcome this drawback. Specifically, calcium sulfoalu...

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Main Authors: Yaxin Tao, Yi Zhang, Geert De Schutter, Kim Van Tittelboom
Format: Article
Language:English
Published: Elsevier 2024-03-01
Series:Developments in the Built Environment
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2666165924000140
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author Yaxin Tao
Yi Zhang
Geert De Schutter
Kim Van Tittelboom
author_facet Yaxin Tao
Yi Zhang
Geert De Schutter
Kim Van Tittelboom
author_sort Yaxin Tao
collection DOAJ
description 3D concrete printing can be used to automatically repair concrete structures, while the practical application is still hindered due to the lack of interfacial bonding. A concept using a chemically reactive coating at the interface is proposed to overcome this drawback. Specifically, calcium sulfoaluminate (CSA) cement paste is retarded by adding borax, and the retarded phase can be destroyed with increased pH. The retarded CSA cement paste is placed as coating on the substrate before the repair process, and 3D printable material is placed against the coating afterwards. After that, the hydration reaction of the retarded paste coating can be re-initiated after contact with high-pH 3D printable material, aiming for high interfacial bonding in a short period. We first characterized the structural build-up and early-age mechanical properties of the 3D printable mixtures. We further evaluated the interfacial bonding of samples in the fresh state using a modified pull-out test and investigated the effect of the fresh properties of the materials on the interfacial bonding. After that, we assessed the bond strength of hardened samples based on a modified pull-off test. Finally, we analyzed the microstructure at the interface region using scanning electron microscopy. Results indicate that the placement of chemically reactive coating improves interfacial bonding, which can be attributed to the fast setting and hardening of the material at the interface. Moreover, the enhancement in interfacial bonding is more effective for those 3D printable mixtures that could potentially provide more hydroxide ions to compensate for the retardation of paste coating.
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spelling doaj.art-3d0799a7771743bda8642c8a1b6ea7522024-03-10T05:12:59ZengElsevierDevelopments in the Built Environment2666-16592024-03-0117100333Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repairYaxin Tao0Yi Zhang1Geert De Schutter2Kim Van Tittelboom3Department of Structural Engineering and Building Materials, Ghent University, Ghent, Belgium; Corresponding author.Department of Structural Engineering and Building Materials, Ghent University, Ghent, Belgium; School of Materials Science and Engineering, Tongji University, Shanghai, ChinaDepartment of Structural Engineering and Building Materials, Ghent University, Ghent, BelgiumDepartment of Structural Engineering and Building Materials, Ghent University, Ghent, Belgium3D concrete printing can be used to automatically repair concrete structures, while the practical application is still hindered due to the lack of interfacial bonding. A concept using a chemically reactive coating at the interface is proposed to overcome this drawback. Specifically, calcium sulfoaluminate (CSA) cement paste is retarded by adding borax, and the retarded phase can be destroyed with increased pH. The retarded CSA cement paste is placed as coating on the substrate before the repair process, and 3D printable material is placed against the coating afterwards. After that, the hydration reaction of the retarded paste coating can be re-initiated after contact with high-pH 3D printable material, aiming for high interfacial bonding in a short period. We first characterized the structural build-up and early-age mechanical properties of the 3D printable mixtures. We further evaluated the interfacial bonding of samples in the fresh state using a modified pull-out test and investigated the effect of the fresh properties of the materials on the interfacial bonding. After that, we assessed the bond strength of hardened samples based on a modified pull-off test. Finally, we analyzed the microstructure at the interface region using scanning electron microscopy. Results indicate that the placement of chemically reactive coating improves interfacial bonding, which can be attributed to the fast setting and hardening of the material at the interface. Moreover, the enhancement in interfacial bonding is more effective for those 3D printable mixtures that could potentially provide more hydroxide ions to compensate for the retardation of paste coating.http://www.sciencedirect.com/science/article/pii/S26661659240001403D concrete printingAutomatic repairChemically reactive coatingInterfacial bondingCSA cement
spellingShingle Yaxin Tao
Yi Zhang
Geert De Schutter
Kim Van Tittelboom
Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
Developments in the Built Environment
3D concrete printing
Automatic repair
Chemically reactive coating
Interfacial bonding
CSA cement
title Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
title_full Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
title_fullStr Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
title_full_unstemmed Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
title_short Interfacial bonding of 3D printable concrete with chemically reactive coating for automatic repair
title_sort interfacial bonding of 3d printable concrete with chemically reactive coating for automatic repair
topic 3D concrete printing
Automatic repair
Chemically reactive coating
Interfacial bonding
CSA cement
url http://www.sciencedirect.com/science/article/pii/S2666165924000140
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AT yizhang interfacialbondingof3dprintableconcretewithchemicallyreactivecoatingforautomaticrepair
AT geertdeschutter interfacialbondingof3dprintableconcretewithchemicallyreactivecoatingforautomaticrepair
AT kimvantittelboom interfacialbondingof3dprintableconcretewithchemicallyreactivecoatingforautomaticrepair