• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.39-42
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• 2001

This paper addresses the development of VP curing equipment for the substitution of autoclave which has several limits in application. This equipment adopt vacuuming and pressurizing processes similarly to the autoclave, but has flexible pressurizing and movable system. The experiments were pursued to determine and to compare specific properties of the specimens produced by three kinds of processes; autoclave, hotpress, and VP. The results show that the VP curing equipment can produce the useful composite material with a little inferior quality to the autoclave, but better than the hotpress. Considering the movability of VP curing equipment, it can be expanded its application to the areas of composite patch-repaired structure in large objects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.77-80
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• 2005

The surface of concrete tiles is weak in moisture that it occurrenced efflorescence, but in the former study we found that it is possible to ensure moisture stability of concrete surface by autoclaving. So this study is to discuss the moisture stability and Physical Properties of high-strength glossy concrete according to time and temperature of autoclave curing. As the results, by increasing time and temperature of autoclave curing, compressive strength and surface hardness increased and glossiness decreased. In the case to 3 hour and $180^{\circ}C$ of autoclave curing, there is not effloescences in mosture stability test.

• Advances in concrete construction
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• v.8 no.2
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• pp.139-144
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• 2019

In this study, the mechanical properties of reactive powder concrete (RPC) with a constant cement to silica fume ratio of 4 were investigated. In the experimental program, reactive powder concretes with steel fiber at different ratios were produced. Five productions using quartz sand with a maximum grain size of 0.6 mm were performed. A superplasticizer with a ratio of 3% of the cement was used for all productions. $40{\times}40{\times}160mm$ prismatic specimens were prepared and tested for flexural and compression. The specimens were exposed to two different curing conditions as autoclave and standard curing condition. Autoclave exposure was performed for 3 hours under a pressure of 2 MPa. It was observed that the compressive strength of concrete, along with the flexural strength exposed to autoclave was quite high compared to the strength of concretes subjected to standard curing. The results obtained indicated that the compressive strength, along with the flexural strength of autoclaved concrete increased as the amount of cement used increases. Approximately 15% increase in flexural strength was achieved with a 4% steel fiber addition. The maximum compressive strength that has been reached is over 210 MPa for reactive powder concrete for the same steel fiber ratio and with a cement content of $960kg/m^3$. The relationship between compressive strength and flexural strength of reactive powder concrete exposed to both curing conditions was also identified.

• Composites Research
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• v.29 no.5
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• pp.315-320
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• 2016

Conventionally, composite aircraft structures are fabricated within autoclave at high pressure. However, autoclave process has several disadvantages including high curing costs and limitation of part size. Recently, out-of-autoclave (OoA) processes have been investigated in many studies to replace conventional autoclave process. A newly developed OoA prepreg, using conventional ovens, can significantly reduce the curing costs and produce autoclave-quality parts. Nevertheless, manufacture of void-free complex shape structure using OoA process presents significant challenges because of the low consolidation pressure. In this study, integrated skin-spar-rib composite part was fabricated using OoA prepreg. And cross-sectional macro- and micro-graphs of the part were examined in order to assess the possibility of replacing conventional autoclave process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.49-50
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• 2015

Recently, by-products from concrete industry are generated in large quantities because of urban redevelopment. Accordingly, waste concrete powder(WCP) inevitably generated in the course of crushing, screening, and separating the waste concrete also show high emission and be increasing gradually, but which is mostly buried with waste concrete aggregate. This is a basic research to increase the value added utilization rate of WCP. We have examined strength characteristic of extruding panel with WCP, depending on the curing methods. The result of study shows similar strength to the base specimen in autoclave curing condition. And in autoclave curing condition, the specimen with WCP of 20% and 30% satisfy the target strength of 14MPa.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.4
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• pp.174-181
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• 2021

Lightweight geopolymers were fabricated by using IGCC (integrated gasification combined cycle) slag and Si sludge which are classified as general wastes (recyclable resources). Three curing methods were tried to investigate the changes in compressive strength and density according to the curing method and immersion time. Immersion period was tried up to 21 days to observe long-term performance in water. Compressive strength of the specimens cured in oven decreased abruptly with an increase in immersion time. Compressive strength of the specimen cured in autoclave was low after 3 and 7 day immersion; however, increased rapidly after 21 day immersion. On the contrary, compressive strength of the specimen cured in autoclave and oven was high but substantially decreased after 21 day immersion. Conclusively, it was speculated that oven curing is effective for the compressive strength development at early age; however, autoclave curing is more desirable for the long-term performance in water.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.545-548
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• 2006

This study has been carried out to examine the properties of concrete according to replacement ratio and curing method of fly ash, in order to increase utilization of it. As the result of experiments, the 7 days of early age strength presented around 20MPa, up to 20% of replacement ratio, which is almost the same strength as non-replacement. However, when the replacement ratio was 30%, the strength was decreased to 16MPa, as 20% reduction compared to the non-replacement condition. In 365 days of long term aging, the strength was 5% higher, up to 20% of the replacement ratio, due to the pozzolanic reaction of fly ash. When the replacement ratio was 30%, it presented similar strength development as the non-replacement condition. Steam curing and autoclave curing increased the short age strength, regardless of the replacement ratio of fly ash; however, they don't have an effect on increasing the 365 days of long term strength. Water curing showed high strength development after 28 days, 51.81MPa, which is around 30% higher than air curing, 38.9MPa, steam curing, 38.6MPa, and autoclave curing, 39MPa. Therefore, water curing was examined as one of the very effective curing methods for developing long term strength of concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.1 no.1
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• pp.9-19
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• 1981

Using superplasticizer or the methods of autoclave curing is the most typical and practical of the ways to make high strength concrete. In this study the high strength concrete piles by way of centrifugal forming and hand compacting, are put to the freezing and thawing test after the process of autoclave curing, water curing after steam curing, or stand water curing. And the relation of such piles to durability, the rate of strength decrease, and the rate of weight variation is shown. The durability of those test piles throughout freezing and thawing test proves to be comparatively sufficient in the above-mentioned curings when the piles contain a proper quantity of air. But it is also acknowledged that without A.E agent, the high strength concrete piles of autoclave curing is higher than those of the other curing in strength, but lower in modulus of dynamic elasticity and their durability factor after the test is much lower.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.465-468
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• 2006

This paper investigates the effect of curing conditions on the strength improvement of polymer-modified mortars using epoxy resin with various curing methods. The polymer-modified mortars using epoxy resin are prepared with various polymer-cement ratios, and subjected to standard, hot water, heat cure and autoclave cures. The epoxy-modified mortars are tested for flexural and compressive strengths at desired curing methods. From the test results, the flexural and compressive strengths of the epoxy-modified mortars are hardly improved by the autoclave and hot water cures compared to the ideal cure of $20^{\circ}C$. Among the four types of curing methods, the strengths of the heat cured epoxy-modified mortars is largely improved. Especially, it is obtained in the mortars sealed with PVDC film.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.218-219
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• 2015

Precast concrete produced in the industry is advantage that easy to manage, and it save construction period in the field. The specimens according to the type of activator for AAS(Alkali-Activated Slag) mortar cured in an autoclave. The specimens of AAS mortar with sodium was shown the high rate of increase of the compressive strength.