• Journal of the Korea Furniture Society
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• 제20권4호
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• pp.339-357
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• 2009

Probability based design(PBD) method is independent of construction materials and uses real material properties unlike allowable stress design(ASD) that depends on small clear specimen property, also give quantitative safety and endurance lifetime of a certain material. Moreover, almost advanced country accepted PBD method instead of ASD method. So it is urgent to convert the current ASD method into the PBD method. However, there are wholly lacking of domestic researches related to current issue, and to solve several points in ASD method and to take advantage of PBD method, the conversion from the ASD method into the PBD method is a worldwide trend. Other domestic construction codes, such as steel or concrete constructions, accept the PBD method as well. Accordingly, to introduce PBD method into wood structural design, general theory, and preliminary data and methods were reviewed. With keeping this in mind, some important contents were reviewed, sorted some points for wood structural design that have distinctions against the other construction materials. Furthermore, the history of PBD method, and statistical data and theories for the PBD method, and preliminary data of resistance and load that are two random variables for the PBD method, and finally the difference between limit state design(LSD) and load and resistance factor design(LRFD) that were two superpowers in the PBD method.

• Journal of the Korean GEO-environmental Society
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• 제14권10호
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• pp.17-27
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• 2013

This paper explores stress release induced by unloading in dry sand. A series of model tests were carried out to measure stresses developed in testing sand during loading and those released during unloading for different boundary conditions. It was found that stress in the sand increased linearly with applied load. At the onset of unloading, almost no stress release was observed. Significant stress release took place when the shear stress in the sand induced by unloading exceeded the frictional resistance and caused movement of sand particles. The initiation and the magnitude of stress release depend on the stress condition prior to unloading, the decrease of external load, and also the frictional resistance in sand. A new conceptual stress-release model was next developed based on the model test results by considering the fundamental frictional behavior of granular materials.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제10권6호
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• pp.44-52
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• 2007

Recently, oystershell wastes cause serious environmental problem and the need for the researches on the recycling of oystershell have been increased and various methods are already in operation. Field plate bearing tests and numerical analysis were performed to investigate the bearing capacity of oystershell filled geotextile gabion which utilized the waste oystershell at the coastal oyster farm site. The waste oystershell mixed soil specimens were prepared for the laboratory test and field test in terms of varying blending ratio of granite soil and oystershell. Based on the cyclic plate load test results, the spring constant, subgrade modulus of ground, and the reinforcing parameters were determined. The field plate load test results indicate that the bearing capacity of the soil ground with the oystershell mixed ratio of 20% is greater than that of the original ground. Two-dimensional numerical analysis was evaluated the expected deformation in the given conditions. Analysis results show a similar characteristics on bearing capacity with the results of the field plate load test. These findings suggest that the oystershells are very promising construction materials for landfill and earth embankment in coastal area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.5-21
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• 2005

Urbanization rates of population range from about 1% in the developed countries to about 4% in developing countries. For a global population that may reach 10 billion within the next 40 years, pressure has arisen for an increase in the large-scale use of wastes and byproducts in construction. Ironically, most of the wastes that need to be recycled are generated in large cities where the need for constructed facilities to serve large population is high. Waste and recycled materials (WRM) that are used in construction are required to satisfy material strength, durability and contaminant teachability requirements. These materials exhibit a wide variety of characteristics owing to the diversity of industrial processes through which they are produced. Several laboratory-based investigations have been conducted to assess the pollution potential and load bearing capacity of materials such as petroleum-contaminated soils, coal combustion ash, flue-gas desulphurization gypsum and foundry sand. For full-scale systems, although environmental pollution potential and structural integrity of constructed facilities that incorporate WRM are interrelated, comprehensive schemes have not been developed for integrated assessment of the relevant field-scale performance factors. In this presentation, a framework for such an assessment is proposed and presented in the form of a flowchart. The proposed scheme enables economic, environmental, worker safety and engineering factors to be addressed in a number of sequential steps. Quantitative methods and test protocols that have been developed can be incorporated into the proposed scheme for assessing the feasibility of using WRM as partial or full substitutes for earthen highway materials in the field.

• Advances in concrete construction
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• 제5권2호
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• pp.145-154
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• 2017

In the present day scenario, concrete construction is rapidly becoming uneconomical and non sustainable practice, due to the scarcity of raw materials and environmental pollution caused by the manufacturing of cement. In this study an attempt has been made to propose recycled aggregates from demolition wastes as coarse aggregate in geopolymer concrete (GPC). Experimental investigations have been conducted to find optimum percentage of recycled aggregates (RA) in GPC by replacing 20%, 30%, 40%, 50% and 60% of coarse aggregates by RA to produce recycled aggregate geopolymer concrete (RGPC). From the study it has been found that the optimum replacement percentage of recycled aggregates was 40% based on mechanical properties and workability. In order to study and compare the flexural behaviour of RGPC and GPC four beams of size $175mm{\times}150mm{\times}1200mm$ were prepared and tested under two point loading. Test results were evaluated with respect to first crack load, ultimate load, load-deflection characteristics, ductility and energy absorption characteristics. Form the experimental study it can be concluded that the addition of recycled aggregate in GPC causes slight reduction in its strength and ductility. Since the percentage reduction in strength and behaviour of RGPC is meager compared to GPC it can be recommended as a sustainable and environment friendly construction material.

• Journal of the Korean Geosynthetics Society
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• 제13권2호
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• pp.21-29
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• 2014

The use of filling material based on cement paste is inefficient at field construction because it needs a lot of the charging mass. In addition, it has environmental problem according to the large amount of cement use because its strength is also larger than criterion. The excavated soil with stabilizer can be used as the filling materials when the bored pile is constructed. Therefore, this paper describes field application of solidified soil for economical efficiency and environment-friendly. The static axial load tests and the load-transfer measurements were performed to examine the axial resistant behavior of the piles. As results, the flowability, segregation and bleeding, and bond strength of filling materials was a good performance than that of the existing cement paste. But the skin friction of pile by PDA was slightly decreased than that of the existing cement paste. However, as pile filling materials, and in terms of economics and environment, the applicability of filling material is considered very effective.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제37권4호
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• pp.705-716
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• 2017

As many environmental pollution problems have arisen, various studies related to the environmental evaluation have been carried out in the construction industry. However, there is no methodology for estimating the environmental load quickly for design alternatives of civil facilities in the design phase. This study aim to establish criteria of works information and designed parts which can efficiently estimate environmental loads of PSC beam bridge based on standard quantity at the early design phase. For this purpose, a detailed environmental loads database was constructed by performing Life Cycle Assessment (LCA) based on detailed design data of 25 bridges. In addition, major work with high impact on environmental load were selected, and the analysis of characteristics of environmental load according to the required materials and 8 impact categories were conducted. As a result, the superstructure accounted for 42.91%. In the superstructure, remicon of the material base and PSC beam work occupied 53.13% and 31.25%. In the substructure, remicon, rebar, and cement, which are material base, accounted for more than 93%. It is expected that this major work and material information for each part of bridge can be utilized in the construction of the model, which can estimate the approximate environmental load, reflecting the characteristics of the structure in the design phase.

• Computers and Concrete
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• 제12권1호
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• pp.37-51
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• 2013

The responses of reinforced concrete slabs subject to an impact loading near the ultimate load range are explored. The analysis is carried out on a simply supported rectangular reinforced concrete slab using a nonlinear explicit dynamic procedure and considering three material models: Drucker-Prager, modified Drucker-Prager, and concrete damaged plasticity, available in the commercial finite element software, ABAQUS/Explicit. For comparison purposes, the impact force-time response, steel reinforcement failure, and concrete perforation pattern are verified against the existing experimental results. Also, the effectiveness of mesh density and damage wave propagation are studied independently. It is shown that the presently adopted finite element procedure is able to simulate and predict fairly accurate the behavior of reinforced concrete slab under impact load. More detailed investigations are however demanded for the justification of effects coming from an imperfect projectile orientation as well as the load and structural surface conditions, including the impulsive contacted state, which are inevitable in an actual impact environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.65-66
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• 2023

Recently, the importance of improving air quality has been greatly highlighted due to environmental problems such as indoor air pollution, and efforts are being made to improve indoor air quality not only in Korea but also around the world. In this situation, this study aims to study the physical properties of cement boards using pearlite with excellent physical adsorption performance due to micropores in materials, expanded graphite that is widely used as a flame retardant to prevent heat transfer in the event of a fire. The experimental items are bending fracture load and impact resistance. The bending destruction load at the fiber mixing rates 1, 2, 3, and 4 (%) did not meet the standard 140N, but the bending destruction load at 5% was 168.2N, and the impact resistance of the fiber mixing rates 1 and 2 (%) could not be measured due to cracks and damage, and the impact resistance at 3, 4, and 5 (%).

• Journal of the Korea Institute of Building Construction
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• 제11권2호
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• pp.189-199
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• 2011

Installation of a proper root barrier in a green roof system is very important in order to protect the concrete slab of roof and the root penetration in the waterproofing layer. To select the proper root barrier materials and methods, it is necessary to understand the environmental conditions affecting the waterproofing-root barrier system in green roof construction site. Therefore, we suggested as the environmental performance indexes four kinds of performance requirements; root penetration, chemical attack by chemical agent or fertilizer, load impact by soil depth and size of plant, and water pressure. The related four test methods were suggested for the inspection of these performance indexes. In this research, we could suggest for kinds of test methods as standard test methods to evaluate the environmental performance of waterproofing-root barrier for greening roof system.