• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.654-658
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• 2006

To solve some problems that reveals in the exiting stickiness problem of the housetop, the housetop finishing impact layer can be displaced by the existing concrete block. By doing in this way, this need is rising that the excess cost should be reduced and the materials should be recycled in repairing. According to the above, this study is going to suggest the basic data on building and using of the dry process method by estimating and analyzing a overall determinate quantity through the experiment on the insulation performance among the capacity items on the outside insulation waterproof dry process suggested. In addition, choosing the building method according to the use, the peculiar property and the importance of the building can be possible by analyzing the defect causes happening in the rooftop insulation and waterproof, suggesting the better method and classifying the most proper choosing methods for the need of the building according to the importance of the main factors.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.481-484
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• 2008

Recently, the recycling and reusing of construction and demolition waste concrete is urgently required because waste concrete is greatly increased according to the rapid increasing of urban redevelopment project, but the problem solution for demand and supply unbalance of fine aggregate is urgently required because of the restriction of collecting sea fine aggregate. So the utilization of high quality recycled fine aggregate using construction and demolition waste concrete as new fine aggregate for construction industry is urgently. Accordingly, In this study, As recycled fine aggregate manufacturing technology with exceeding in economical efficiency, reduction efficiency of environmental load and quality improvement effect of recycled fine aggregate, it is to develop dry manufacturing system composed specific gravity separator of high-speed rotation impact type and centrifugal Force Powder Collector, etc. And it is to examine mechanism of recycled sand dry manufacturing system.

• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.147-163
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• 2013

Gonggeomji, located at the outlet of intermontane basin in the upper reaches of Dong River, is known as being constructed in the late Unified Silla Dynasty. Extensive wetlands were developed before the construction of embankment at Gonggeomji and very compact silty layers were deposited during dry seasons. Paniceae was cultivated on a dry field in the basin during the early Bronze and Iron Ages. Although it is supposed that agricultural activities on a paddy and dry field prevailed during the Three Kingdoms Age, the indicating layer was not found. As the construction of the embankment, Oryza sativa as well as Paniceae were cultivated in the basin at the same time. The climates during the early Bronze are cool and Iron Ages are estimated to be generally warm. From the late Unified Silla Dynasty and middle Goryeo Dynasty when the embankment was constructed, it was still warm, and then, shows alterations between cool and warm conditions. Since the late Goryeo Dynasty, it gradually became cool.

• Geotechnical Engineering
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• v.12 no.1
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• pp.47-62
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• 1996

The bedding zone which influence directly to the safety of dam is supporting the face slab under hydraulic load in concrete faced rockfill dam. In case that leakage is developed due to various ruptured joint or cracks of face slab and etc., the bedding zone should limit the leakage by low permeability and keep the internal stability. In this study for the proper coefficient of permeability various properties, such as gradation, dry density, performance of embankment work and etc. were analysed. The results from the large scale test of permeability and density are summerized as follows : 1. Coefficient of permeability is decreased clearly by increase of dry density. 2. The particles smaller than the No.4 strive( p,) greatly influences the permeability under dry density of 2.24t 1 m3. 3. In case of C.40 and p,40%, even if dry density decreased to 2.0t/m3, the permeability coefficient is assumed to u x1-scm/s and internal stability is abtained. 4. Generally in dam construction since dry density and uniformity coefficient of bedding zone were higher than 2.2t/m3 and 50 respectively p, of 30~40% is assumed to be suitable and permeability coefficient of below 1$\times$10-3cm l s is expectable.

• Advances in concrete construction
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• v.7 no.3
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• pp.175-181
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• 2019

Low-calcium fly ash (LCFA) were used to prepare cement/LCFA specimens in this study. The basic physical properties including water demand, fluidity, setting time, soundness and drying shrinkage of cement/LCFA paste were investigated. The effects of curing time, immersion time and wet-dry cycles in 3% $Na_2SO_4$ solution on the compressive strength and the microstructures of specimens were also discussed. The results show that LCFA increases the water demand, setting time, soundness of cement paste samples. 50% and 60% LCFA replacement ratio decrease the drying shrinkage of hardened cement paste. The compressive strength of plain cement specimens decreases at the later immersion stage in 3% $Na_2SO_4$ solution. The addition of LCFA can decrease this strength reduction of cement specimens. For all specimens with LCFA, the compressive strength increases with increasing immersion time. During the wet-dry cycles, the compressive strength of plain cement specimens decreases with increasing wet-dry cycles. However, the pores in the specimens with 30% and 40% LCFA at early ages could be large enough for the crystal of sodium sulfate, which leads to the compressive strength increase with the increase of wet-dry cycles in 3% $Na_2SO_4$ solution. The microstructures of cement/LCFA specimens are in good agreement with the compressive strength.

• Steel and Composite Structures
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• v.42 no.1
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• pp.33-48
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• 2022

This paper researches a lightweight composite structure referred to as the Profiled Steel Sheeting Dry Board (PSSDB). It is fundamentally produced by connecting a Profiled Steel Sheeting to Dry Board using mechanical screws. It is mainly employed as floor panels. However, almost all studies have focused on researching the one-way structural performance. Therefore, this study focuses on the bending behaviour of the two-way PSSDB floor system using both of Finite Element (FE) and Experimental analysis. Four panels were used in the experimental tests, and a mild steel plate has been applied at the bottom for two panels. For the FE process, models were created using ABAQUS software. 4 parametric studies have been utilized to understand the system's influential elements. From the experimental tests, it was found that using Steel Plate shall optimize the two-way action of the system and depending on the type of dry board the improvement in stiffness may reach up to 38%. It was shown from the FE analysis that the dry board, profiled steel sheeting and steel plat can affect the system by up to 10 %, 17% and 3% respectively, while applying a uniform load demonstrate a better two-way action.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.120-121
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• 2019

The construction industry is known to be one of the representative industries that generate fine dust. Therefore, reducing the amount of fine dust generated in construction sites is very important for the overall fine dust management. Based on this, this study proposed the concept of fine dust measurement and removal technology combined with advanced technologies such as drones and IoT. The qualitative, quantitative and risk elimination effects that can be expected when applying the proposed technique are analyzed. We will verify the effectiveness of the proposed concept through system development and field application, and evaluate specific economic feasibility through cost analysis. The proposed concept will be validated through system development and field application and evaluated specific economics through cost analysis.

• Land and Housing Review
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• v.14 no.1
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• pp.115-122
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• 2023

Modular construction is popular as a smart building system because it can shorten the construction period. This study proposed a precast concrete (PC) core system that can further shorten modular construction time. The system was developed and its structural performance was verified through computational analysis. The proposed PC core system is a complete PC construction method using dry bonding. The results of the study indicated that the proposed PC core system has structural stability and performance suitable for modular housing.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.953-956
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• 2008

The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire.resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire.resistant boards.According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116$^{\circ}$C in 15mm, 103.8$^{\circ}$C in 20mm, and 94$^{\circ}$C in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3.hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.211-218
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• 2013

Cyclic wet and dry conditions in the marine environment structures corrosion is known to be the fastest rising. For that reason, accelerated corrosion test methods for the reproduction of tidal environment has been actively conducted. However, many studies have estimated threshold value for steel corrosion or concentrated in chloride penetration analysis. In this study, cyclic wet and dry conditions to reproduce the structure of the environment in accelerated corrosion and chloride penetration test analysis was performed. Corrosion was determined by the result of reinforcement corrosion monitoring based on galvanic potential measurement and half-cell potential method. Accelerated corrosion test results for each formulation was different corrosion periods, the order OPC> FA> BS> High-strength concrete. FEM durability interpretation program DuCOM was conducted under the same conditions as in accelerated corrosion test. The experimental RCPT tests demonstrated the validity of the result.