• Korean Journal of Computational Design and Engineering
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• v.22 no.1
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• pp.37-43
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• 2017

3D printing techniques can be used in various application fields and many researches have been reported. FDM (Fused Deposition modeling) can make multi-material or multi-color models with the simultaneous use of two or more filaments. In a dual-nozzle FDM printers, while the active nozzle is working, the remaining nozzle will be idle. The remaining molten resins inside an idle nozzle can ooze out unwantedly. The spill over from the resting nozzle produces unwanted remaining on the fabricated product. In this research, we suggest a method for optimizing building position of a model to minimize the unwanted spill-over that could possibly contaminate the final product. The method is based on minimizing the two intersection volumes. The first intersection volume is obtained by intersecting the volume defined by the first material and the Minkowski sum between the volume of the first material and the vector obtained by subtracting the center point of the first nozzle from the center point of the second nozzle. The second intersection volume can be obtained by reversing the role of the first and second volumes and nozzles. Some results obtained from the implementation using the Parasolid (Siemens) geometric modeling kernel is presented.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.65-71
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• 2007

Since pop-outs are occurred recently on concrete surface occasionally, it is needed to find out accurate causes and to suggest appropriate methods. On this study, it is investigated the occurrence mechanism of pop-outs caused by electric arc furnace Oxidizing slags as fine aggregate for concrete. As a result, it is investigated the cause of pop-outs that extremely small quantities of free CaO and free MgO in the electric furnace slag react with water to produce $Ca(OH)_2$ and $Mg(OH)_2$, so that their volumes are expanded and erupted about two times. As a resolution, it is needed to remove the potential cause of expansion by replacing the deteriorated concrete section up to the depth to secure the safe of structural element with repairing polymer mortar, especially more than 50MPa.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.239-242
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• 2009

As the high-rise building increase due to the gravitation of population to big cities recently, it requires high quality and high performance of Concrete. As a result, people are keenly interested in Meta-kaolin as new admixture favorable from an economic perspective, which has strength and endurance with admixture at the same level like Silica-fume. Accordingly, as to Meta-kaolin, this study was to set by three levels like domestic one, foreign one, and Silica-fume, the water-binding material ratio 25%, and four level substitute like 0, 10, 20, and 30(%) in order to compare and analyze the quality durability of high-concrete according to the substitute of Meta-kaolin applicable with replacement of Silica-fume. As a result of performing experiment it was found that when water-binding material ratio increases, resistance of neutralization, carbonation, salt damage and sulfate decrease, and when replacement ratio of mineral admixture increases, depth of accelerating carbonation gets greater. Also, the combination of SF and MK-B favored resistance to chloride ion penetration better than MK-A, and it was found that when replacement ratio of binding material increases, the resistance to sulphuric acid increases. Therefore, based on this study, it was understood that meta-kaolin is useable in replacement of silicafume.

• Advances in concrete construction
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• v.13 no.2
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• pp.153-162
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• 2022

Prefabricated exterior wall panel is the main non-load-bearing component of assembly building, which affects the comprehensive performance of thermal insulation and durability of the building. It is of great significance to develop new prefabricated exterior wall panel with durable and lightweight characteristics for the development of energy-saving and assembly building. In the prefabricated sandwich insulation hanging wall panel, the selection of material for the outer layer and the arrangement of the connector of the inner and outer wall layers affect the mechanical performance and durability of the wall panels. In this paper, high performance cement-based composites (HPFRC) are used in the outer layer of the new type wall panel. FRP bars are used as the interface connector. Through experiments and analysis, the influence of the arrangement of connectors on the mechanical behaviors of thin-walled composite wall panel and the panel with window openings under two working conditions are investigated. The failure modes and the role of connectors of thin-walled composite wallboard are analyzed. The influence of the thickness of the wall layer and their combination on the strain growth of the control section, the initial crack resistance, the ultimate bearing capacity and the deformation of the wall panels are analyzed. The research work provides a technical reference for the engineering design of the light-weight thin-walled and durable composite sandwich wall panel.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.826-829
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• 2004

An increasing interest in fire safety engineering can currently be identified in Korea and overseas. The fire-resistant characteristics of spray coating material for fire protection with or without nano $Al(OH)_3$ colloid has been experimentally investigated and the results are presented in this paper. The fire-resistance characteristics of spray coating material with nano $Al(OH)_3$ were superior to those without $Al(OH)_3$. Especially, spray coating material with nano material showed that thermal characteristic in the early days was remarkably excellent.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.516-521
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• 2004

TEEE(Thermoplastic ether-ester elastomer) is expected to reduce the noise and vibration from railway because its unique properties such as porosity. in this study, after building TEEE rail pad at established rail, we conducted practical test and vibration test to inquire the field application and endurance of TEEE material. The test results showed that TEEE material was lower vibration than EVA material, therefore, TEEE material was effective from a vibration reduction point of view.

• KIEAE Journal
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• v.4 no.3
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• pp.113-119
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• 2004

As Building Integrated Photovoltaic(BIPV) system replaces the conventional building finishing materials with PV modules, two function of electricity generation and building envelope can be expected. Therefore BIPV can be a good alternative technology for the 21 century environment-friendly buildings. The objective of this paper is to develope BIPV modules for a commercial buildings of which structure is mainly light-weight, curtain wall system. Two types of module are developed for a opaque part and a transparent part of building envelope. Current technology level and market status of Korea determines the configuration of developed BIPV modules. Architectural considerations for the integration of PV module to building envelope such as building structure, construction type, safety, regulation, maintenance etc. have been carefully reflected from the early stage of BIPV module design. Especially the survey result of current building envelope materials determines the size of unit BIPV modules and a unique cladding method for PV module installation is developed. Trial product of BIPV modules and cladding hardwares are manufactured and sample construction details for a demonstration building are proposed.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.125-132
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• 2007

The use of Self-Leveling material is increasing recently. This paper assesses the quality of surface layer of concrete floor when Self-Leveling material is defective. The paper shows how to predict the defect of SL material before construction begins. The relationship between the quality of surface layer of concrete floor and the defect of SL material was determined and the quality of surface layer of concrete floor was then estimated. The relations between the quality of surface layer and the defect of SL material were determine considering surface strength, moisture, and consistency of surface layer. Absorbing amount was used as the indicator of consistency and the absorbing amount of test material was measured. Then the relations between the test material and surface strength were determined. Generally concrete floor with greater consistency has greater surface strength, however in this study, we hound that high impact concrete floor could have lower surface strength as the consistency gets bigger. The relations between the level of defect occurred in SL material and the quality of surface layer were examined and we clarified that the surface layer with lower consistency gets higher possibility to occur exfoliation in early stage, one or two weeks after constructing SL material. When the consistency is sufficient, the occurring situation of defect depends upon the moisture of surface layer. Little amount of moisture gets higher possibility not to occur the defect. As the amount increases, fissure generates and early exfoliation may occur. In addition, the level of fissure is highly related with the surface strength.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.923-924
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• 2012

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.213-214
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• 2016