• Journal of Construction Engineering and Project Management
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• v.4 no.2
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• pp.41-46
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• 2014

RCC consumes large quantities of natural resources like gravel stone and steel, and there is a need to investigate on an innovative material that utilizes limited quantities of natural resources but should have good mechanical strength. This study deals with the experimental investigation of strength evaluation of cementitious composites reinforced with polyolefin fibers from 0% to 2.5% (with interval of 0.5%), namely Polyolefin Fiber Reinforced Cementitious Composites (PL-FRCC) and developing statistical regression models for compressive strength, splitting-tensile strength, flexural strength and impact strength of PL-FRCC. Paired t-tests (for each PL fiber percentage 0 to 2.5%) bring out that there is significant difference in compressive and splitting-tensile strength when curing periods (3, 7, 28 days) are varied. Also, a strong relationship exists between the compressive and flexural strength of PL-FRCC. The proposed mathematical models developed in this study will be helpful to ascertain the mechanical strength of FRCC, especially, when the fiber reinforcing index is varied.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.1
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• pp.1-8
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• 2014

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction. The proposed reinforcement details have economic feasibility and rationality and make construction periods shorter. A model of hollow reinforced concrete bridge columns was tested under a constant axial load and a quasi-static cyclically reversed horizontal load. As a result, proposed reinforcement details for material quantity reduction were equal to existing reinforcement details in terms of required performance. The companion paper presents the experimental and analytical study for the performance assessment of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.3
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• pp.107-115
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• 2013

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction. The proposed reinforcement details has have economic feasibility and rationality and makes construction periods shorter. A model of column sections with reinforcement details for material quantity reduction was tested under quasistatic monotonic loading. As a result, the proposed reinforcement details for material quantity reduction was were equal to existing reinforcement details in terms of the required performance. In the a subsequent paper, the an experimental and analytical study will be performed for the performance assessment of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction will be performed.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.79-89
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• 2000

The application of stabilization method has increased because of short construction periods, no environmental problems with dumped and replaced soil, assurance of required strength and economical effect with mid to small size construction. The unconfined and triaxial(UU-condition) compression tests were executed with each mixing sample for the study of the improvement effects and the effect of design-parameters by the stabilization methods. Three typical stabilizers, which are representative in Korea, were applied in this study, and three common soils(very soft clay, general weathered soil, common clay), which are common in Korea, were used in this study. In this study, the effect of engineering factors(soils, stabilizers and water contents, etc.) which are important parameters for the improvement effects of mixed ground by stabilizers, was analyzed. As results, the tendencies of design-parameters(unconfined compression strength, deformation modulus and strength parameter) are presented and the criteria of the application of stabilization methods are suggested.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.104-111
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• 1998

Statistical analyses of occupational accidents associated with construction work were carried out to explore the basic statistical characteristics of their damage consequences. Emphasis was placed upon the probabilistic and statistical analyses to clarify, in particular, the relationship between frequency of labour accidents and their damage consequences. Damage consequences were classified into two categories such as the number of workdays lost due to accidents and the number of injured workers involved in one accident. Two types of accident data were collected for the analyses. From the analyses, it was found that the relation between damage due to accidents and their frequencies can be represented by a simple power function which indicates a log-log linear relation. By making use of this relationship, various probabilistic evaluations such as the estimation of the mean time periods between accidents, expected damage consequences, and expected damage ratio between different mean time period of accidents were conducted.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.143-144
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• 2018

It was 15 years since the remodeling system was introduced in 2001 and the remodeling system was implemented due to the amendment of the housing law. From now on, the remodeling will be settled in the direction of important apartment houses, and planning will be the core plan of remodeling. Up to now, the remodeling system has changed according to the market situation, and the planning plan has also changed based on the laws and regulations. In this background, this study summarizes the changes of the regulations related to the remodeling plan and examines the characteristics of the plan according to the changes of the regulations. The remodeling plan can be divided into three periods according to the changes of the regulations, and the contents of the regulations and the characteristics of the plan have been clarified.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.202-203
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• 2018

Chemistry and microstructure of steel reinforcement bars play an important role to control the corrosion in concrete environments. In present study, we have chosen two different microstructure of steel rebars produced from companies and assessed their corrosion characteristics in simulated concrete pore (SCP) solution with prolonged exposure periods. Hot rolled steel rebar showed more corrosion resistance compare to thermo-mechanically treated (TMT) one. The growth of passive is greater in hot rolled (A) than TMT (B) due to orientation of microstructure. TMT steel rebar exhibit distorted microstructure with many micro cells which enhances the galvanic coupling and induce the deterioration while on the other hand hot rolled rebars exhibit fine grain boundary which responsible in growth of uniform, adherent and protective passive film resultant improved impedance was observed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1073-1078
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• 2000

This study is to investigate the effect of construction element such as the number of CFS ply, curing temperature, splice length and curing periods on the mechanical properties of Carbon Fiber Sheet (CFS). Through the tensile tests of CFS specimens, it can be said that the reduction factor stemmed from the number of CFS ply must be considered in the calculation of the design tensile strength of CFS. Also, the minimum splice length of CFS and curing period in $20^{\circ}C$ to satisfy the standard tension strength of CFS are over 5cm and after 3days, respectively. The measuring error of epoxy resin have no effect to tension strength of CFS until $\pm$20% error.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.83-84
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• 2020

In present study, we have deposited the Zinc coating using arc thermal spray and plasma arc spray processes onto the steel substrate and durability of the deposited coating was evaluated. The bond adhesion result shows that plasma arc sprayed Zn coating exhibited higher in its value compared to arc thermal spray. SEM shows that Zn coating deposited by plasma arc process is more compact, less porous and adherent compare to arc spray process. The corrosion resistance properties are evaluated in artificial ocean water solution with exposure periods. EIS results show that total impedance at 0.01 Hz of plasma arc sprayed coating is higher than arc thermal spray owing to the compact and less porous morphology. It is concluded that plasma arc sprayed Zn coating is better than arc thermal spray process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.179-180
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• 2022

In this study, analyzed the effect of using CGS before and after the pre-treatment process as fine aggregate on the resistance to sulfate attack in concrete. As a result of the analysis, Although it showed a similar tendency to Plain (CS100), it is judged that it is necessary to analyze the resistance to sulfate attack due to the increase in immersion periods such as 180 days and 365 days.