TY - JOUR
T1 - Towards a model for structural performance in concrete printing based on buildability and toolpath design
AU - Duarte, Gonçalo
AU - Duarte, José Pinto
AU - Memari, Ali
AU - Brown, Nathan
AU - Gevaudan, Juan Pablo
N1 - Funding Information:
This research was financially sponsored by The Pennsylvania State University , Gulf Concrete Technology (GCT) , Hilti Foundation, and Xtreme Habitats Institute . The authors express their gratitude to Dr. Sven Bilén, Dr. Ali Memari, Dr. Aleksandra Radlińska, Dr. Ming Xiao, Dr. Negar Ashrafi, Mr. Nathan Watson, Mr. Hanbin Cheng, Mr. Zhengyu Wu for their valuable insights and contributions to this research.
Publisher Copyright:
© 2023
PY - 2023/6/15
Y1 - 2023/6/15
N2 - Characterizing the early age viscoelastic behavior of extruded cementitious materials remains a critical issue for 3D concrete printing (3DCP) technologies because the fabrication of large-scale structures requires modeling the behavior beyond the fresh state. This paper provides a model for structural performance that highlights the connection between rheological and mechanical testing results in the fresh state, the relevance of the post-fresh state in buildability for 3DCP, and the impact of toolpath design on hardened state behavior. The overall results show that buildability for 3DCP is largely dependent on post-fresh state behavior and is characterized by thixotropy, early structuration, setting, and hardening properties. The rheological results indicate that oscillatory strain rheology combined with a pre-shear protocol that replicates the shear history of the printing components is a valid method to evaluate fresh state stiffness. In addition, post-fresh state buildability was shown to depend on a mixture of both flexural and plastic collapse in the design of overhang elements. Finally, the toolpath design settings that resulted in a filament overlap ranging from 9% to 25% improved the mechanical performance by promoting the bonding of filaments and minimized anisotropic behavior. The model resulting from this study will be used to create a computational tool to support designers in the design of structures for 3DCP, which will be the subject of a future publication.
AB - Characterizing the early age viscoelastic behavior of extruded cementitious materials remains a critical issue for 3D concrete printing (3DCP) technologies because the fabrication of large-scale structures requires modeling the behavior beyond the fresh state. This paper provides a model for structural performance that highlights the connection between rheological and mechanical testing results in the fresh state, the relevance of the post-fresh state in buildability for 3DCP, and the impact of toolpath design on hardened state behavior. The overall results show that buildability for 3DCP is largely dependent on post-fresh state behavior and is characterized by thixotropy, early structuration, setting, and hardening properties. The rheological results indicate that oscillatory strain rheology combined with a pre-shear protocol that replicates the shear history of the printing components is a valid method to evaluate fresh state stiffness. In addition, post-fresh state buildability was shown to depend on a mixture of both flexural and plastic collapse in the design of overhang elements. Finally, the toolpath design settings that resulted in a filament overlap ranging from 9% to 25% improved the mechanical performance by promoting the bonding of filaments and minimized anisotropic behavior. The model resulting from this study will be used to create a computational tool to support designers in the design of structures for 3DCP, which will be the subject of a future publication.
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U2 - 10.1016/j.jobe.2023.106325
DO - 10.1016/j.jobe.2023.106325
M3 - Article
AN - SCOPUS:85150466569
SN - 2352-7102
VL - 69
JO - Journal of Building Engineering
JF - Journal of Building Engineering
M1 - 106325
ER -