• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.263-264
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• 2023

3D printing technology is recognized as a core technology that will lead the next generation, and is a field that can have a large ripple effect if it innovates the existing construction production method. Therefore, this study deals with the development of a 3d printing system using an articulated robot for construction purposes. In this system, ABB robot was used to control the developed cement gun accurately. The system is composed of mixer to mix cementitious materials, pump to transfer the materials, abb robot to motion control and cement gun to extrude the materials to print required construction parts. Using the system developed in this study, a suitable mix ratio of cementitious materials was found and successively printed a 1m high structure that demonstrated possibility of printing structures using 3d printer. In the future, we plan to build a foundation for automated construction through research on construction methods and materials that can be continuously layered for the system.

• Construction Engineering and Management
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• v.23 no.5
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• pp.30-33
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• 2022

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.731-739
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• 2017

As Additive Manufacturing (AM), so-called 3D printing technology, has become visualized, its potential for Mass-Customization, production costs and time savings has extended the scope of utilization to the architecture domain. Several cases that produced facilities, building elements and components using 3D printing technology have been announced mainly on the outside. There is also the development of foundation technologies including 3D printing-specific materials and equipment in Korea. As 3D printing technology in the architecture domain is currently in the early stages of adoption, realistic and systematic strategies are needed to advance it to the commercialization stages, considering the current circumstances of the industry. With this background, this study surveyed experts to investigate the status of the perception of 3D printing technology for adoption in domestic architecture industry. 3D printing technology is expected to be commercialized in areas of irregular-shape buildings and interior markets rather than general construction area. 3D printed products expected to be commercialized are limited to the level of building elements and the aesthetic factor is regarded as the most competitive factor. To enhance the possibility of the commercialization of 3D printed products, the 3D printing-specific construction method, related policies and systems are required along with the performance and stability of the materials and equipment.

• Magazine of RCR
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• v.15 no.3
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• pp.33-39
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• 2020

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.33-40
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• 2024

The volume of shells, a prominent form of marine waste, is steadily increasing each year. However, a significant portion of these shells is either discarded or left near coastlines, posing environmental and social concerns. Utilizing shells as a substitute for traditional aggregates presents a potential solution, especially considering the diminishing availability of natural aggregates. This approach could effectively reduce transportation logistics costs, thereby promoting resource recycling. In this study, we explore the feasibility of employing wasted shell aggregates in 3D concrete printing technology for marine structures. Despite the advantages, it is observed that 3D printing concrete with wasted shells as aggregates results in lower strength compared to ordinary concrete, attributed to pores at the interface of shells and cement paste. Microstructure characterization becomes essential for evaluating mechanical properties. We conduct an analysis of the mechanical properties and microstructure of 3D printing concrete specimens incorporating wasted shells. Additionally, a mix design is proposed, taking into account flowability, extrudability, and buildability. To assess mechanical properties, compression and bonding strength specimens are fabricated using a 3D printer, and subsequent strength tests are conducted. Microstructure characteristics are analyzed through scanning electron microscope tests, providing high-resolution images. A histogram-based segmentation method is applied to segment pores, and porosity is compared based on the type of wasted shell. Pore characteristics are quantified using a probability function, establishing a correlation between the mechanical properties and microstructure characteristics of the specimens according to the type of wasted shell.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.113-118
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• 2020

The purpose of this study is to evaluate the shrinkage characteristics of the cement-based composite for 3D printing construction, and to evaluate the shrinkage before/after extrusion and after printing during the printing process. As a result of evaluating the compressive strength by curing age of OPC-mix and printing-mix, similar trends were shown until 7 days of age, but the maximum shrinkage of 252 ㎛/m was larger in the case of OPC-mix compared to printing-mix. During the printing process, the compressive strength of the cementitious composite material after extrusion was about 6.5 MPa lower than the material before extrusion until the 7th day of age, but the level of strength on the 28th day of age was similar. As for the shrinkage characteristics, the result of shrinkage after printing showed greater shrinkage in the range of 220-260 ㎛/m compared to the result of shrinkage before extrusion.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.375-382
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• 2019

In this study, an experimental study on the buildability of the structure using the developed printing materials and equipment was performed. Experimental variables included the moving speed of nozzles(=80 and 100mm/s), the revolutions per minute (RPM) of screw in discharge buckets, and the aspect ratio(=1.67 and 5.00) reflecting wall length of the structures. Buildability of the 3D printed concrete structures was analyzed based on the maximum decomposition layer and collapse patterns of the structures according to the experimental variables. The nozzle movement speed of 80mm/s and the aspect ratio of 1.67 were favorable for 3D printing in this study. The collapse process of structure due to uneven layer decomposition was also analyzed through the relative displacement measurement of the lower part of the structure during printing.

• Magazine of RCR
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• v.18 no.4
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• pp.69-73
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• 2023

• Magazine of RCR
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• v.19 no.1
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• pp.57-60
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• 2024

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.338-347
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• 2021

This paper aims to evaluating the interlayer strength of 3D-printed concrete with interlayer reinforcement. According to lap splices, two reinforcement methods were considered. One method did not include lap splices of interlayer reinforcement, but the other method included lap splices with length of 40mm. In addition, two different curing conditions were applied: air curing conditions and water curing conditions. The compressive, splitting tensile, and flexural tensile strengths of 3D-printed concrete specimens were measured in three loading directions with different reinforcement methods and curing conditions. Splitting and flexural tensile strengths decreased considerably when tensile stresses acted over the interlayers of 3D-printed concrete specimens. However, the flexural tensile strength or interlayer bonding strength of the printed specimens increased significantly at the interlayers when the longitudinal interlayer reinforcement penetrated printed layers. Interlayer bonding strength of printed concrete decreased after air curing treatment was applied because interlayers of printed concrete with more pores formed by the air cu ring conditions are more vulnerable to the load.