• Carbon letters
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• v.12 no.1
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• pp.53-56
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• 2011

This study aimed to investigate the influence of mesoporous carbons on the thermal insulation properties of epoxy/mesoporous carbon composites. The mesoporous carbon (CMK-3) was prepared by conventional templating method using SBA-15. The epoxy/mesoporous carbon composites were prepared by mixing the synthesized CMK-3 with diglycidylether of bisphenol A (DGEBA). As experimental results, the curing reactivities of the DGEBA/CMK-3 composites were found to decrease with the addition of the CMK-3. Also, the thermal conductivities of DGEBA/CMK-3 composites were found to decrease with increasing CMK-3 content. This could be interpreted in terms of the slow thermal diffusion rate resulting in pore volume existing in the gaps in the interfaces between the mesoporous carbon and the DGEBA matrix.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.87-88
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• 2023

In this study, as a fundamental research to establish the mechanism of carbonate precipitation, we compared and evaluated the mechanical properties of cement paste under different carbonation conditions. The research results showed that as the CO₂ concentration increased, the compressive strength also increased.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1773-1782
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• 1994

In this paper, the expert cure system for carbon fiber epoxy composite materials, which controls the temperature and pressure of the autoclave according to the several rules, was developed to manufacture better composite products in shorter curing time. The rules were based on the on-line measured quantities such as the dielectric properties and temperature of the composites and the pressure of the autoclave. The curing time and the mechanical properties of the composite materials manufactured with the expert cure system were compared to those of the specimens manufactured with the conventional cure cycle.

• Carbon letters
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• v.15 no.1
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• pp.67-70
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• 2014

In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.

• Magazine of the Korea Concrete Institute
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• v.28 no.4
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• pp.40-45
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• 2016

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.252-256
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• 2007

A series of spherical porous carbons were prepared via resorcinol-formaldehyde (RF) sol-gel polymerization in the presence of cationic surfactant (CTAB, cetyltrimethylammonium bromide), wherein the carbon sphere size was controlled by varying the CTAB introduction time after a pre-determined period of addition reaction (termed as "pre-curing"). The sphere size gradually decreases with an increase in the pre-curing time within the range of 30-150 nm. The carbons possess two types of pores; one inside carbon spheres (intra-particle pores) and the other at the interstitial sites made by carbon spheres (inter-particle pores). Of the two, the surface exposed on the former was dominant to determine the electric double-layer capacitor (EDLC) performance of porous carbons. As the intra-particle pores were generated inside RF gel spheres by gasification, the pore diameter was similar for all these carbons, thereby the pore length turned out to be a decisive factor controlling the EDLC performance. The charge-discharge voltage profiles and complex capacitance analysis consistently illustrate that the smaller-sized RF carbons deliver a better rate capability, which must be the direct result of facilitated ion penetration into shorter pores.

• Carbon letters
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• v.1 no.3_4
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• pp.154-157
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• 2001

Composite adsorbents were prepared by mixing water plant sludge with phenolic resin having the ratio of 1 : 1, 1 : 2, and 1 : 3 respectively, curing from $100^{\circ}C$ to $170^{\circ}C$ under $N_2$ atmosphere, and then activating with $N_2$ at $700^{\circ}C$. Thermal property, specific surface area and morphology of the composite adsorbents as well as their precursors were measured by TGA, BET and SEM respectively. Removal efficiency of the composite adsorbents to ${NH_4}^+$ and TOC was compared with those of commercial zeolite and activated carbon. The adsorbents presented very promising TOC removal efficiency of 98%, which was identical level to that of commercial activated carbon while they displayed removal efficiency, only 32%, of ${NH_4}^+$. Therefore, this composite adsorbent considered as the alternative material of commercial activated carbon, used as an expensive removal agent of organic substances and THM in water treatment plant and it also suggested a possibility of practical application in other processes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.766-771
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• 2016

This study examined the long-term durability of PC boxes, which was manufactured by low-carbon eco-friendly concrete using an alternative binder to cement and alternative fine aggregate to sand and microwave heat curing system to reduce the construction cost of a near-surface transit system. Based on the test results, the initial compressive strength of microwave heat cured concrete was higher than that of the steam cured concrete, but those were similar in the long-term age. In addition, there was no significant difference between the two curing conditions in the chemical resistance and the freeze-thawing resistance, and the chloride ion penetration level of the concrete cured by two methods was very low. Therefore, low-carbon eco-friendly concrete and microwave heat curing technology are expected to contribute to the economic construction of a near-surface transit system, and reduce carbon dioxide emissions and environmental impact.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.11-15
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• 1990

Results of an experimental study on the manufacture and the mechanical properties of carbon fiber reinforced fly ash-cement composites are presented in this paper. The carbon fiber reinforced fly ash-cement composites using silica powder and a small amount of Ethylene vinyl acetate emulsion are prepared with carbon fiber, foaming agents and curing conditions. As a result, the manufacturing process technology of carbon fiber reinforced fly ash-cement composites is developed. And the mechanical properties such as compressive, tensile and flexural strengths and drying shrinkage of lightweight carbon fiber reinforced fly ash-cement composites are improved by using a small amount of Ethylene vinyle acetate emulsion. The development and applications of precast products and the design systems of lightweight carbon fiber reinforced fly ash-cement composites are expected in the near future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.257-258
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• 2012

With regard to the carbon reduction that has become an international problem, we have examined the effects of compressive strength of the ground granulated blast-furnace slag mortar with the curing temperature. Also, we evaluated the mechanical properties of steel slag powder produced during the steelmaking process in order to examine the possibility as admixture.