• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.40-44
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• 2009

This is a comparative structural analysis for a steel roof LNG storage tank that has some advantages relatively in designing larger scale tanks and construction cost, etc. compared with a conventional concrete roof LNG storage tank as the capacity of LNG storage tanks is bigger. Structural analysis was performed on a 200,000$k{\ell}$ steel roof LNG storage tank and a concrete of the same capacity in condition of three critical load combination cases, a normal operation, a LNG spillage and seismic case by using finite element method. And comparative structural safety evaluation was carried out by using strength ratio in places of concrete wall, foundation and roof with a quantitative method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.113-116
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• 2008

In these days, properties of concrete has been demanded to be high performance because concrete structure was bigger and higher. So studies on high strength concrete and lightweight concrete has been frequently done. But lightweight concrete has been used to limited non-structural elements in th country. Lightweight aggregate mixed with lightweight concrete was only coarse aggregate in case of the structural lightweight concrete. In the country studies on the lightweight concrete was poor and unvaried. Also it is difficult to be practical use of lightweight concrete was that it has been expensive. It was study on the using fine lightweight aggregate with lightweight concrete to crushed by-products and wastes to get to make foamed glass with recycled glass. So it was tested by fine aggregate standard and mixed with.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.247-248
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• 2010

This study is of manufacturing artificial lightweight aggregates using industrial wastes. The ingredients for manufacturing lightweight aggregate were stone sludge and bottom ash for main materials, and steel slag(SS), glass abrasive sludge(GS) and blast furnace slag(BS) respectively for accessory material. Their precursors were sintered in the range of $1,050{\sim}1,150^{\circ}C$ for 5 min. The sintered results show that the lightweight aggregate with SS had low water absorption ratio and density at $1,150^{\circ}C$. There's a possibility that if GS is used more than the range of this study, GS can be manufactured lightweight aggregate. But it is judged that BS are incongruent to be used for a raw material of lightweight aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.321-324
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• 2008

This paper presents the results of the performance of compression-type anchor for CFRP tendon. As the results of previous tests, the principal variables for enhancing performance of anchor were sleeve dimensions, inserts, compression pressure, etc. A total of 18 specimens were tested for the performance of compression-type anchor with various inner shapes. Test results revealed that the length of sleeve increased along with the performance of anchor up to 18-22%. Also, the performance of anchor was susceptible to the length of sleeve compared to the surface treatment with the oxide.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.533-536
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• 2006

A light-weight aggregate with a surface layer was fabricated using glass abrasive sludge and expanding agents. The glass abrasive sludges were mixed with expanding agents ($Fe_2O_3,\;graphite,\;CaCO_3$) and formed into precursors. These precursors were sintered in the range of $700-900^{\circ}C$ for 20min. The sintered light-weight aggregate had a surface layer with smaller pores and an inner region with larger pores. The surface layer and pores controlled the water absorption ratio and physical properties. As the expanding agent fraction and the sintering temperature increased, the porosity and pore size increased. The light-weight aggregate with $Fe_2O_3$ and graphite as the expanding agents had a low water absorption ratio while the porous material with $CaCO_3$ as the expanding agent had a higher water absorption ratio and more open pores.

• Journal of the Society of Disaster Information
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• v.8 no.2
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• pp.100-107
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• 2012

The main purpose of this research is to propose advanced bridge-decks surfacing from the examples of In-Cheon bridge with Guss asphalt and Gyul-Hyeon bridge with stone matrix asphalt(SMA) concrete. The research results presented that the Guss asphalt concrete pavement was weak when rutting was developed due to the low resistance at high temperatures. The SMA concrete pavement demonstrated good resistance to plastic deformations and was easy to maintain pavement conditions. The results mentioned above are generalized in developed counties where surfacing pavement techniques for steel bridge-decks are advanced. However, due to the lack of construction experiences in Korea, appropriate construction guidelines and organized research for the steel bridge deck pavements are necessary for more advanced steel bridge decks surfacing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.143-151
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• 2006

This paper presents the comparison of the goodness-of-fit test of analytical bond models between concrete and steel or GFRP reinforcements. Bond test specimens were prepared in accordance with the CSA codes and the rebars used in the test were steel and two types of commercial GFRP rebar products. Using the test data, a bond model was proposed, and comparison of goodness-of-fit test for existing bond models and proposed bond model was carried out by the least squares method. The result indicates that the proposed bond model has better goodness-of-fit test than the existing ones.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.39-48
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• 2015

Reinforced concrete (RC) structures strengthened with FRP materials would cause the loss of the reinforcing effect and the sudden failure of the structure due to the debonding of FRP. The debonding fracture strength of the FRP-strengthened concrete structures has been evaluated using the same strength method as applied in RC structures based on the debonding strain of FRP. However, the values of the FRP debonding strain are different according to design guidelines. Thus, this study carried out an experimental study on RC beams reinforced with GFRP and evaluated the debonding fracture strength of the strengthened beams from each design guideline. Since the debonding failure occurs prior to reaching the ultimate value of concrete compressive strain, this study accounts for the nonlinear stress distribution of concrete. This study also proposed equations that can evaluate the debonding strength of GFRP-strengthened RC beams with similar safety to the ultimate flexural strength of non-strengthened RC beams.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.689-696
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• 2008

The purpose of this study was to evaluate the alkali-silica reactivity for aggregates in Korea according to test methods: accelerated mortar bar test (AMBT) by ASTM C 1260; chemical test by KS F 2545 (ASTM C 289). The results are as follows: The AMBT (ASTM C 1260) results showed that two (2) igneous rocks (two mica granite and felsite), three (3) sedimentary rocks (arkose, red sandstone and shale), two (2) metamorphic rock (slate and vitric tuff), one (1) mineral (quartz) showed more expansion than 0.1% at 14 days. But, some sedimentary rocks and metamorphic rocks expanded more than 0.1% at 28 days even though they were less than 0.1% at 14 days. Therefore, it is necessary to extend the experimental dates more than 14 days to evaluate the possibility of alkali-aggregate reactivity. The chemical test (KS F 2545) results showed that five (5) igneous rocks (andesite, diabase, granite porphyry, muscovite granite and diorite) were indicative of potentially deleterious expansion, while two (2) igneous rocks (diorite porphyry and quartz porphyry) were possible indicative of expansion, and three (3) igneous rocks (biotite granite, two mica granite and felsite) were indicative of innocuous reactivity. The above results showed that the results from chemical method (KS F 2545) and AMBT (ASTM C 1260) had little relationship.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.121-127
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• 2011

In this study, possible use of indigenous natural loess (Hwangtoh) as a new binding material via geopolymerization process is examined. Hwangtoh pastes with four different mix proportions of varying alkali liquid concentrations (6 M, 8 M) and the constituents of the binder as well as the alkali liquid at a constant liquid-to-binder ratio of 0.55 were prepared. Analysis of the natural loess (Hwangtoh) paste was carried out as follows : 1) Measurement of compressive strength and weight of cubic specimens versus curing time; 2) Analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) about reaction product; 3) Porosity analysis of hardened Hwangtoh paste. The result showed that it is possible to prepare Hwangtoh paste with 29.1 MPa at the age of 7 day by using alkali solution (made as 1 : 4.5 the mass ratio of liquefied $Na_2SiO_3$ and NaOH solution and applying the curing temperature of $60^{\circ}C$). Compressive strength development with respect to the degree of moisture evaporation from the paste seems to be independent of curing temperature. Therefore, it seems that higher early strength of the paste specimens cured at higher temperature can be attributed to both higher rate of reaction and moisture evaporation.