• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.99-106
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• 2020

Man-made slope is inevitable to make a new road, which may result in environmental problems as well as collapse of slope. To prevent these problems, various methods such as geogrid reinforced retaining wall, precast concrete-panel retaining wall, and so on, have been introduced and developed. Among these methods, this paper presents the evaluation of field application of precast concrete-panel retaining wall attached to in-situ ground (so called top-down) compared to the conventional construction method of precast concrete-panel retaining wall (so called bottom-up) through the field test and numerical analysis. As a result, the safety factor of both methods in final stage is similar, however, top-down method guarantees the slope stability during the construction compared to bottom-up method.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.498-505
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• 2022

In this study, as a result of eva lua ting the quality properties of Living Concrete, the flow of the table showed a tendency to decrease as the mixing ratio of ocher increased. Compressive strength was found to decrease with increasing loess mixing ratio. Density properties were evaluated for weight reduction, As a result of comparison with the panel using cement as a comparison group, the density was measured to be a bout 20 % lower than that of the cement panel, and it is judged that it is less affected by the load and can be installed in the structure. As a result of evaluating the panel temperature reduction, there was a difference in the temperature reduction with time. It is judged that the panel planted with moss has a lower temperature than the panel without moss, so it is judged that it can be used in a vertical greening system.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.198-203
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• 1995

The objective of this study is to provide the information on the techniques of manufacturing and experiment in small scale modeling of precast concrete(P.C.)large panel structures. The adopted scale was 1/5th 4types of experiments were performed : material tests for model concrete and model reinforcement, compressive test of horizontal joint, shear test of vertical joint and cyclic static test of 2-story subassemblage structure. Based on the experimental results, the following conclusions are drawn: (1)Model concrete may have in general larger compressive strength than expected. (2) Model reinforcement can show less ductility if the annealing processes were performed without using vaccuum tube. (3) Failure modes of horizontal and vertical joints were almost same for both prototype and model. But the strength of model appears to be higher than required by similitude law. (4)Hysteretic behavior of 1/5 scale subassemblage model can be made quite similar to prototype's if the ductility of model reinforcement and compressive strength of model concrete could be representative of those of prototype.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.775-780
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• 2002

Sandwich panel made by foamed styrene and ployuretane has been used generally in the construction area because of the high thermal conductivity and light weight but they occur harmful gases to both bodies and environments in the high temperature over $50^{\circ}C$. So, the purpose of this study is to investigate the physical properties of light-weight panel using the non-structural lightweight aggregate as a part of the substitution of foamed styrene and ployuretane. This paper dealt with the effect of the addition of polymer dispersion such as SBR, St/BA-1 and St/BA-2 having polymer-cement ratio as 5, 10, 15% and the filling ratio of continuous void as 50, 60% on the strength of polymer-modified sandwich panel core. From the results, we could know that the compressive and flexural strength of the sandwich panel core using non-structural lightweight aggregate and polymer dispersion such as SBR, St/BA-1 and St/BA-2 tended to be increased with an increase in the polymer-cement ratio and the filling ratio of continuous void.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.53-57
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• 2011

Recently due to dramatically increasing demand of liquid crystal display (LCD) panel in IT industry, the used LCD panel glass has been wasted from electronic items, and also panel glass of poor quality during manufacturing process. The wasted LCD panel glass was crushed in the range of 0.42 to 2mm and evaluated for its usefulness as a aggregate in production of cement concrete brick. Cement concrete specimens with various mixing ratios of weathered granite soil, LCD panel glass and cement were cured in wetness for 7 days at $40^{\circ}C$ and then tested for uniaxial comprehensive strength (UCS)(KS F 4004 method). Specimen with a mixing ratio, 1:6:3, of weathered granite, LCD panel glass and cement, respectively, showed the highest average in the UCS test($26.51N/mm^2$). It is much higher than that of commercial brick without glass($17.00N/mm^2$). Conclusively waste LCD panel glass can be reutilized economically as a raw building material of good quality.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.105-110
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• 2002

This paper proposes an analytical method to predict the behavior of reinforced concrete beams subjected to reversed cyclic loading. The proposed method is based on the compatibility aided truss model and adopts the stress vs. strain curve of concrete which considers the softening effects. This model Is verified by comparing to the six reinforced concrete panel tests.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.629-634
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• 2003

The cement-based composites have relatively low tensile strength and toughness. The fiber addition is one of the most important ways of increasing the toughness of concrete. The steel fibers have been used conventionally in the shotcrete of tunnel lining. Recently, the structural synthetic fibers were developed and used frequently in some actual tunnel shotcreting in foreign countries. There are so many method to evaluate a toughness; ASTM, JCI, EFNARC, etc. But these methods contain a few defects. So most researchers are studying to develope a new toughness evaluation method. A RTA is one of these methods. The purpose of this study is to explore the strength and toughness characteristic of the fiber reinforced concrete panel according to the geometry; diameter, thickness. The result were compared with those of steel fiber reinforced concrete.

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.142-151
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• 1994

Though stiffnesses of joints in precast concrete(P.C.) large panel structures are known to be generally less than those in monolithic reinforced concrete wall structures, designers have very little information on the quantitative values with regards to these stiffnesses. The aim of this paper is to provide this quantitative information, in particular, on the compressive stiffness of horizontal joints, based on the analytical results derived from several experiments. Also, it is shown that the approach from the contact problem to determine this stiffness gives a value very simlar to those obtained above.

• Earthquakes and Structures
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• v.11 no.4
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• pp.723-740
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• 2016

Reinforced concrete corbels are generally used to transfer loads within a structural system, such as buildings, bridges, and facilities in general. They commonly present low aspect ratio, requiring an accurate model for shear strength prediction in order to promote flexural behavior. The model described here, originally developed for walls, was adapted for corbels. The model is based on a reinforced concrete panel, described by constitutive laws for concrete and steel and applied in a fixed direction. Equilibrium in the orthogonal direction to the shearing force allows for the estimation of the shear stress versus strain response. The original model yielded conservative results with important scatter, thus various modifications were implemented in order to improve strength predictions: 1) recalibration of the strut (crack) direction, capturing the absence of transverse reinforcement and axial load in most corbels, 2) inclusion of main (boundary) reinforcement in the equilibrium equation, capturing its participation in the mechanism, and 3) decrease in aspect ratio by considering the width of the loading plate in the formulation. To analyze the behavior of the theoretical model, a database of 109 specimens available in the literature was collected. The model yielded an average model-to-test shear strength ratio of 0.98 and a coefficient of variation of 0.16, showing also that most test variables are well captured with the model, and providing better results than the original model. The model strength prediction is compared with other models in the literature, resulting in one of the most accurate estimates.

• Computers and Concrete
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• v.22 no.3
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• pp.327-336
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• 2018

Increase in population and its daily increasing in our today society results in an increase in housing demand while traditional methods are not applicable. The project preparation and realization processes, based on theoretical and empirical studies, a creation of goods, services, and technologies, are the most important human activities. Selection of effective technological systems in construction is a complex multi-criteria decision-making task. Many decision-makers refuse innovations once faced with similar difficulties. Therefore, using modern materials and methods in this industry is necessary. Modern methods increase quality and construction speed in addition to decrease energy consumption and costs. One of the problems in the way of any project is selecting construction system compatible with the project needs and characteristics. In the present research, different concrete structures such as common reinforced concrete (RC) structure, prefabricated, Insulating Concrete Formwork (ICF), 3D Panel and Tunnel Concrete Formwork (TCF) for buildings with limited floors in Iran are studied and compared from the viewpoint of different criteria like cost, time, applicability and technical characteristics with industrialization approach. Therefore, some questionnaires filled out by construction industry experts in order to compare criteria and sub-criteria in addition to evaluation of optimized structural systems. Then, results of the questionnaires ranked by Analytic Hierarchy Process (AHP) and the most effective alternative selected. The AHP results show that 3D Panel system 36.5%, ICF 21.7%, TCF 19.03%, prefabricated system 13.3% and common RC system 9.3% are the most and the least efficient systems respectively.