• Corrosion Science and Technology
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• v.6 no.5
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• pp.219-226
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• 2007

Pre-construction primer (PCP), or shopprimer, have been applied to steel plates to control temporary corrosion during ship fabrication. For surface preparation at ship block stage, in common shipyard practices, welding beads, burnt and rusted areas shall be blasted or power tool cleaned and the contamination such as zinc salt shall be removed with blasting or power tool. Whereas, the sound film of PCP needs not to be removed or roughened as the paint having good compatibility with PCP is used for the first coat. In many cases, however, full blasting or sweep blasting on the sound PCP treated block assemblies was requested. There still has been argument about the legitimacy of this practice, thus, it is critical to evaluate the quality of the coating system applied on the sound PCP retained condition, comparing with the one applied on the full blasted or sweep blasted condition. In this study, two different epoxy systems for water ballast tank were applied on the surfaces with sound PCP condition, full blasted condition, and sweep blasted condition. Coating performances such as durability, anti-corrosion, cathodic disbondment resistance were evaluated. The test results clearly indicated that the sound film of PCP needed not to be removed or roughened as the paint having good compatibility with PCP based on inorganic zinc silicate.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.108-116
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• 2004

After the IMF financial crisis, a lot of risks in construction industry have been increased gradually with the expansion of construction industry widely, higher stories of building, and the expansion of the underground space and excavation work. These risks are bringing out construction accidents such as the death, the injury of worker and so on, not so much as it would be effected the corporation's image. In spite of these situations, many construction industries still maintain the wrong methods and not try to decrease construction accidents. Recently, we should focus on the fact that management system of the larger construction also is being good, on the other hand, the condition of the work in the case of smaller construction industries is very poor, construction company have a particular safety management system but it has a difference according to the construction magnitude, construction companies have a particular safety management system but it has a difference depending on the construction according to the construction magnitude. Therefore, this study will suggest the developed way of construction safety management by the comparison and analysis from the difference between the higher and the smaller construction industries.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.471-477
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• 1999

A new stress, load and displacement controlled direct shear apparatus has recently been developed at the Hyundai Institute of Construction Technology This direct shear apparatus is capable of testing of rock joint under constant normal stiffness, constant normal stress or constant normal load boundary conditions. This paper describes this direct shear apparatus and illustrates results of shear tests at constant normal stress condition, constant normal load condition and constant normal stiffness condition with dental stones which have a same joint roughness and unconfined compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.695-702
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• 2002

Shotcrete (or Sprayed concrete) has been used as an important support material in New Austrian Tunnelling Method (NATM). Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell, NMT (Norwegian Method of Tunnelling) has been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrcte linings, high performance shotcrete providing high strength, high durability, better pumpability has to be developed in advance as an integral component. This paper presents the Ideas and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) in sump water condition. In order to increase early strength, a new approach using high-early strength cement with liquid alkali-free accelerator has been investigated From the results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early strength improvement compared to the ordinary portland content and good bond strength even under sump water condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.219-220
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• 2011

The research is for building safety by using fiber reinforced concrete against impact load. The aim of this study is to evaluation of Impact Resistance of mortar by Reinforcement Condition of Aramid Fiber(fiber length, fiber surface treatment, fiber contents, hyrid reinforcement with steel fiber). Thus, the results indicate that it can improve mix condition and impact resistance by fiber surface treatment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.209-210
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• 2011

This study is aimed to draw a optimum combined fiber mix condition to improve spalling resistance and flowability of ultra high-strength concrete. As a result, W/B 12.5% concrete specimens were prevented spalling with PE0.05+ PP0.1, PE0.05+NY0.1 and W/B 12.5% concrete specimens were prevented spalling with all of combined organic fiber mix condition. But There is no significant influence of steel fiber under 5% volume ratios to prevent spalling. In the scope of this study, we suggest that condition of optimum volume ratio PE0.05+NY0.1 is to improve spalling resistance, flowability and residual compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.9-10
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• 2017

In case of the concrete is poured into the HPC(Hollow Precast Concrete) column, the shrinkage condition of the HPC surface and the infilled concrete may be different, causing an interfacial space and deteriorating the integration performance. In this study, manufacturing HPC column mold and and the drying shrinkage properties with the charging concrete were examined. As a result, case of the shrinkage reducing agent showed the best drying shrinkage reduction effect. In the case of the expansive agent, the length change was lower than that of plain, but the difference from the shrinkage reducing agent was large, so it is considered that mixing condition of expansion mixing condition should be improved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.26-27
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• 2017

In this study, the cracking characteristics of cured pastes at 800℃ were investigated by X-ray CT. The test specimens were fabricated with and without aggregate, and the heating rate condition was applied at rapid heating (10.0℃/min). It is considered that the rapid heating condition does not cause a temperature gradient phenomenon because the temperature difference between the surface and the center of the sample is small due to a low heating rate unlike an actual fire. The cracking condition of the specimens without aggregate was more severe than that of specimens with aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.289-290
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• 2012

In this study, it was evaluated about shrinkage properties of high strength concrete according to poly mix fiber and moisture evaporation condition. As a results, When concrete was mixed with poly mix fiber of spalling control, it reduced effect of shrinkage independent of the evaporation conditions of unsealed and sealed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.27-28
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• 2018

In this study, water vapor pressure and restrained stress were evaluated by ring-type restrained condition for compressive strength 60 and 80MPa concrete. Experimental results show that the 80MPa concrete has higher water vapor pressure and restraint stress than the 60MPa concrete, resulting in spalling occurrence. It is because, the higher the compressive strength of the concrete, the more dense the internal structure is formed.