• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.119-123
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• 1995

This paper presents an accelerated-curing method by the war water method and discusses how these methods can be adapted for regular quality control and quality assurance of concret. Accelerated strength test data can be used for estimating the furture stength, e.g. the 28-day strength. An accelerated-curing method to predict the 28-day strength of concrete from 1-day warm water-cured test results was evaluated in the laboratory and the field. For these evaluations test are performed for 1845 standard specimens from 123 different batches of concrete. The results of this study the equation applicable universally with resonable accuracy are presented for estimating the potential strength of concrete by the warm water-curing method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.301-307
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• 1997

This paper is evaluated for properties of aggregate and antiwashout admixture not only to minimize segregation and water contamination of underwater concrete but also to meet concrete quality required. Two antiwashout admixtures used in this study were available domestically and slump flow, pH, setting time, and filing property of fresh concrete and the compressive strength, flexural strength under water and in the air under 2 different curing conditions ($10^{\cire}C$ and $20^{\cire}C$ ) were measured. Compressive strength ratio of specimens cured in and water temperature $10^{\cire}C$ /$20^{\cire}C$ added HPEC and HPMC was 64% and 89%, respectively. Relative compressive strength of 2 kinds observed higher concrete added HPEC, 3% at $10^{\cire}C$ curing temperature, 34% at $20^{\cire}C$ . The flexural strength of specimens made under water was 1/4~1/6 of compressive strength similar to the existing data in the literature.

• 한국건설순환자원학회논문집
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• 제6권2호
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• pp.87-93
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• 2018

건설 구조물에서의 고강도 콘크리트 사용은 꾸준히 증가하고 있다. 그러나 고강도 콘크리트는 상대적으로 낮은 물-바인더비를 가지고 있어 초기 재령에서 수화과정에 발생하는 수화열 및 수축 등으로 인해 균열 등과 같은 문제점이 발생으로 인해 그 대책이 시급한 실정이다. 최근에 수축을 저감할 수 있는 방법으로 내부양생에 대한 관심이 대두되고 있으며 연구가 활발히 이루어지고 있다. 본 연구에서는 고강도 및 하이볼륨 모르타르에 대해 인공경량골재(LWA)를 이용하여 내부양생 효과를 검증하고 여러 현장조건을 고려하여 양생조건(기중, 습윤, 수중)에 따른 압축강도 영향에 대한 연구를 수행하였다. 자기수축 실험을 통해 고강도 및 플라이애시를 혼입한 하이볼륨 모르타르에서 인공경량골재 혼입률이 증가할수록 수축저감 효과가 커지는 것을 확인하였다. 양생조건에 따라 압축강도 영향은 조금씩 다른 경향을 보이고 있으며, 기중 및 습윤 조건에서는 일반적으로 강도를 증가시키고 수중조건에서는 감소하는 것으로 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제18권2호
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• pp.99-107
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• 2014

본 연구에서는 순환골재 콘크리트의 성능에 대한 양생방법의 영향에 대하여 실험적으로 고찰하였다. 순환골재 콘크리트 제조를 위하여 부순골재에 순환골재를 0, 25, 50, 75 및 100%로 대체하였으며, 증기양생한 콘크리트의 압축 및 쪼갬인장강도, 투수공극, 염소이온 침투저항성 및 건조수축을 소정의 재령에서 측정하여 수중양생한 콘크리트의 성능과 비교하였다. 실험결과에 따르면, 양생방법에 관계없이 순환 골재 대체율이 증가할수록 콘크리트의 역학적 성능은 감소하였다. 한편, 초기재령에서 증기양생된 콘크리트는 수중양생된 콘크리트와 비교하여 매우 우수한 성능을 나타내었다. 그러나, 장기재령 (28일)에서 증기양생의 효과는 초기재령에 비하여 두드러지게 나타나지 않음을 알 수 있다. 결론적으로, 본 연구의 범위 내에서 순환골재 콘크리트의 성능향상을 위하여 증기양생법의 적용이 유용할 것으로 판단된다.

• 한국염색가공학회지
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• 제17권6호
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.115-116
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• 2016

This study applied BS replacement mortar's ERCO to see what impact it has on moisture evaporation and contraction changes, and resulted in the following. Depending on the rate of change in length according to the cure method of BS replacement mortar, high-strength areas were shown to have a bigger increase in the rate of change in length than regular or low-strength areas, and differences in rate of change in length due to ERCO cure methods were shown to be slight. For rate of changes in mass, on the whole there was an increase in the order of dry curing, cover curing, 7-day water curing, and28-day water curing. A comprehensive view says that after removal of test piece specimens, ERCO application did not expect a sufficient curing effect in the BS area.

• 콘크리트학회논문집
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• 제12권5호
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• pp.25-34
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• 2000

When concrete is placed underwater, it is diluted with separating cementitious material and as a result the quality of concrete becomes poor. To solve this problem, antiwashout underwater concrete is increasingly used for the construction and repair of the concrete structure underwater. The objective of this study is to investigate the characteristics of antiwashout underwater concrete as to the mix proportion, casting and curing water through experimental researches. The unit weight of water and cement, water-cement ratio, fine aggregate ratio, unit weight of antiwashout underwater agent and superplasticizer, and casting and curing water were chosen to measure the suspended solids, pH, air contents, slump flow, unit weight of hardened concrete, and compressive strength. From this study, the incremental modulus at mix proportion design and unit weight of antiwashout underwater agent were increased more than fresh water, and it is a optimum mix proportion that the unit weight of water(and cement) is 230kg/$\textrm{m}^3$(460kg/$\textrm{m}^3$), waterOcement ratio is 50%, fine aggregate ratio is 40%, unit weight of antiwashout underwater agent is 1.2% of water contents per unit weight of concrete, and unit weight of supeplasticizer is 2.5% of cement contents per unit weight of concrete when the antiwashout underwater concrete is used for the underwater work of ocean.

• International Journal of Concrete Structures and Materials
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• 제4권1호
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• pp.9-15
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• 2010

Silica fume is a common addition to high performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-hour continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turnaround time. Various steam curing durations were utilized with full-scale precast prestressed pile specimens. The concrete compressive strength and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica fume concrete met all FDOT requirements for the 12, 18 and 24 hours of curing periods. No shrinkage cracking was observed in any samples up to one year age. It was recommended that FDOT allow the 12 hour steam curing for concrete with silica fume.

• Elastomers and Composites
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• 제33권2호
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• pp.93-102
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• 1998

In electric cable industries, the curing extent of the rubber materials covering the electric cores gives an significant effect on their final performance. The curing extent of rubber is controlled mostly by pull-out velocity of cable in the extrusion process. The final curing extent may be different for different radial positions inside the rubber because of the non-uniform temperature distributions during the curing process. In this contribution, the prediction of curing extent distribution throughout the radial direction of rubber is represented when the cable is passing through the steam curing zone with a fixed pull-out velocity. The prediction of the optimum pull-out velocity for the desired curing extent distribution is also reported. The steady-state heat balance was developed for the curing and cooling processes in which the pull-out rubber was cured by high temperature steam and then cooled by ambient water. A few essential material properties such as density, specific heat, and thermal conductivity were measured to analyze the temperature distribution during the curing and cooling processes. The times to reach 90% curing extent at varying temperatures were measured and used to determine the final cure extent distribution inside the rubber.

• KCI Concrete Journal
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• 제12권1호
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• pp.79-89
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• 2000

This research developed an accelerated curing processe for cellulose fiber reinforced cement composites using vigorous reaction between carbon dioxide and cement paste. A wet-processed cellulose fiber reinforced cement system was considered. Carbonation curing was used to complement conventional accelerated curing. The parametric study followed by optimization investigation indicated that the carbonation curing can enhance the productivity and energy efficiency of manufacturing cellulose fiber reinforced cement composites. This also adds environmental benefits to the technical and economical advantages of the technology.