• Resources Recycling
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• v.23 no.4
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• pp.37-46
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• 2014

Carbon dioxide generated from construction materials and construction material industry among the fields of construction is approximately 67 million tons. It is about 30% of the carbon dioxide generated in the fields of construction. In order to reduce carbon dioxide in the fields of construction, it is necessary to control the use of fossil fuel consumed and decrease carbon emission by reducing the secondary and tertiary curing generating carbon dioxide in construction material industry. Therefore, this study manufactured mortar by having cement as the Plain and substituting three binding materials up to 50% and then adopted different curing methods to analyze congelation and strength characteristics. Test results for strength property by changing binding materials showed that specimens with blast furnace slag, CSA 15% and CAMC 5% resulted in positive effect for strength.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.2
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• pp.68-76
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• 2022

This study was performed to investigate the mechanism of the change in compressive strength of autoclave cured geopolymers. Specimens were immerged in distilled water, 2M, 8M, and 14M alkaline solutions for 3, 7, and 21 days. The change in the specimens immersed in a short period of time was not significant, but the compressive strength of the specimens immersed in the distilled water and 8M alkali solution) for 21 days increased more than twice as much as before immersion because of additional geopolymerization. However, compressive strength decreased due to the alkaline aggregate reaction when alkaline solution was supplied more than a certain level of concentration. Therefore, immersing the specimens for more than 21 days in the distilled water or 8M alkaline solution would be desirable for the improvement of compressive strength of autoclave cured specimens.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.166-173
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• 2019

In this paper, the reaction properties of silica source in the accelerated curing conditions using autoclave and the fundamental properties of inorganic Micro Defect Free(MiDF) concrete using silica source are studied. Studies show that Si ions elution rate from silica source in autoclave curing is higher in amorphous source. In tap water conditions, solids which is source after autoclaved curing show a higher mass reduction in amorphous materials, which is attributed to the higher elution rate of ion. In $Ca(OH)_2$ solution conditions, amorphous materials show higher mass increase, due to increase in C-S-H minerals. From experiment for influence on the properties of MiDF concrete by using nano silica materials, the specimen with silica fume shows an increase in compressive strength and a decrease in absorption depending on replacement rate up to 5.5%, while nano silica with amorphous phase and high-fineness shows a decrease in compressive strength and decrease in the water absorption. The specimen with nano silica increases the pore below 10,000nm, but reduces pore between 10,000 and 100,000nm. The above results show that the porosity and absorption rate of MiDF concrete can be reduced by using amorphous nano-size silica. However, to reduce the pore of 50 to 10,000nm, better dispersion of nano material in the cement matrix will be necessary. We will focus on the this item in the next research.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.172-175
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• 2001

The co-cured Joining method, which is regarded as an adhesively bonded Joining method, is an efficient joining technique because both curing and bonding processes for the composite structures can be achieved simultaneously. It requires neither surface treatment onto the composite adherend nor an additional adhesive joining process because the excess resin, which is extracted from composite materials during consolidation, accomplishes the co-cured Joining process. Since the adhesive of the co-cured joint is the same material as the resin of the composite adherend, the analysis and design of the co-cured joint for composite structures are simpler than those of an adhesively bonded joint, which uses an additional adhesive. In this paper, effects of the manufacturing parameters, namely surface roughness, stacking sequence of the composite adherend, and manufacturing pressure in the autoclave during curing process, on the tensile load bearing capacity of the co-cured single lap joint will be experimentally investigated.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.31-39
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• 1997

This research is to evaluate the effect of sunshine treatment on the strength in the Al 6061/AFRP hybrid composite(APAL). APAL specimens were processed by autoclave curing system under the constant condition of curing temperature, time and aluminum surface pertreatment. Aramid patched aluminum alloy can be widely used for the repair of the damage part of the aircraft. The tensile strength of the sunshine treated APAL 2P and 6P composite is 14%, 22% smaller than that of the non-treated material. The interlaminar shear strength of the APAL specimens for the adhesive length of 5mm is 24% higher than that of the APAL for the adhesive length of 10mm. In the case of APAL DS 1P material, interlaminar shear strength of the specimen which was sunshine treated for 200 hours is 21% smaller than that of the non-treated material while interlaminar shear strength of the specimen which was immersed in a 70.deg. C fresh water for 1200 hours decreases by 75.7%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1045-1047
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• 2017

In this study, we focused on development of the all-in-one case insulation for end-burning solid rocket motors. Material of insulation used unvulcanized rubber based on EPDM/kevlar. In case of boots insulation, preforms was made by using hot press molding, and then the tape was inserted between two preforms for all-in-one curing in the case. Finally bladder method was applied for curing of insulation.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.76-79
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• 2005

Bending deformation and energy absorption characteristics of aluminum-composite hybrid tube beams have been analyzed for improvement in the bending performance of aluminum space frame by using experimental tests combined with theoretical and finite element analyses. Hybrid tube beams composed of glass fabric/epoxy layer wrapped around on aluminum tube were made in autoclave with the recommended curing cycle. Basic properties of aluminum material used for initial input data of the finite element simulation and theoretical analysis were obtained from the true stress-true strain curve of specimen which had bean extracted from the Al tube beam. A modified theoretical model was developed to predict the resistance to the collapse of hybrid tube beams subjected to a bending load. Theoretical moment-rotation angle curves of hybrid tube beams were in good agreement with experimental ones, which was comparable to the results obtained from finite element simulation. Hybrid tube beams strengthened by composite layer on the whole web and flange showed an excellent bending strength and energy absorption capability.

• Computers and Concrete
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• v.18 no.5
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• pp.937-950
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• 2016

This study applied autoclave expansion and heat curing to accelerate the hydration of concrete and investigated how these methods affect the expansion rate, crack pattern, aggregate size effect, and expansion of electric arc furnace oxidizing slag (EOS)-containing concrete. An expansion prediction model was simulated to estimate the expansion behavior over a long period and to establish usage guidelines for EOS aggregates. The results showed that the EOS content in concrete should range between 20% and 30% depending on the construction conditions, and that coarse aggregates with a diameter of ${\geq}4.75-mm$ are not applicable to construction engineering. By comparison, aggregates with a size of 1.18-0.03 mm resulted in higher expansion rates; these aggregates can be used depending on the construction conditions. On Day 21, the prediction model attained a coefficient of determination ($R^2$) of at least 0.9.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.270-271
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• 2014

In this study, a replacement ratio of blast furnace slag coarse aggregate and a water binder ratio by an optimum combination of PHC file was investigated. As a results, the target strength 78.5MPa was altogether satisfied in a mix proportion 28-G100-SG0 and W/B ratio 26 %. The surface rupture was generated in 28-G0-SG100 combination after curing with the autoclave. According to the result of measuring the ingredient, the majority were the MgOH2 hydrate.

• Resources Recycling
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• v.24 no.2
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• pp.13-22
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• 2015

$CO_2$ emitted from building materials and construction materials industry reaches about 67 million tons, which occupy about 30 % of $CO_2$ emitted from the construction field. Controls on the use of consumed fossil fuels and reduction of emission gases are essential for the reduction of $CO_2$ in the construction area as we reduce the second and third curing to emit $CO_2$ in the construction materials industry. Accordingly, this study applied the low energy curing admixture (hereinafter "LA") to the extruded panels to observe the physical properties, depending on the mixing amount of fiber, type of fiber and mixing ratio of fiber. The type of fiber did not appear to be a main factor to affect strength, while the LA mixing ratio and mixing amount of fiber appeared to be major factors to affect strength. Especially, the highest strength was developed when the LA mixing ratio was 40%, whereas the test object with the mixing ratio of 50% resulted in the decrease of strength. In addition, it appeared that the mixing ratio of fiber greatly affected flexural strength and strength increased as the mixing ratio increased.