• 콘크리트학회논문집
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• 제12권1호
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• pp.89-99
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• 2000

The objective of this study is to investigate the bond strength properties of antiwashout underwater concrete. The arrangement of bars (vertical bar, horizontal upper bar, horizontal lower bar), condition of casting and curing (fresh water, sea water), type of fine aggregate (river sand, blended sand(river sand : sea sand = 1:1), and proportioning strength of concrete (210, 240, 270, 300, 330kgf/$\textrm{cm}^2$)are chosen as the experimental parameters. The test results(ultimate bond stress) are compared with bond and development provisions of the ACI Building Code(ACI 318-89) and proposed equations from previous research(which was proposed by Orangun et. al). The experimental results show that ultimate bond stress of antiwashout underwater concrete which arranged bar on the horizontal lower, used the blend sand, and was cast and cured in the fresh water are higher that other conditions. The ultimate bond stress were increased in proportion to {{{{( SQRT {fcu }) }}3 2. From this study, rational analytic formula for the ultimate bond stress are to be from compressive strength of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.457-460
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• 2003

This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing pozzolanic materials such as fly ash (FA), blast furnace slag (SG) and metakaolin(MK). For the experiments, pH value, suspended solids, slump flow, efflux time and compressive strength were tested. According to the results from compressive strength test, MK10 showed the very high compressive strength characteristic during the entire curing days, but the rate of strength development was decreased as time goes by.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.27-28
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• 2022

In this study, the mechanical properties of resource-recycling concrete containing concrete sludge waste as main materials was compared depending on whether supercritical CO2 curing was applied for the realization of CCU technology. After supercritical CO2 curing, the compressive strength of the steam-cured specimen was lowered, but it was confirmed that the compressive strength of the underwater-cured specimen was improved.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.141-142
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• 2019

In this study, we conducted a comparative analysis of the effects of retention time and resuscitation method on the degree of resuscitation after reapplying mortar with much FA replacement. Results After applying NaOH to the top surface of 60 % FA-substituted mortar, the degree of resuscitation at $40^{\circ}C$ was high enough to increase the overall curing time, but there was no significant difference. However, with regard to the curing method, middle curing showed the greatest manifestation, followed by wrapping and underwater curing, but there was no significant difference. The resuscitation level on the 28th of the lumber was found to be revived to about 70~80 % at around 30 % without resuscitation.

• 한국결정성장학회지
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• 제31권6호
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• pp.247-257
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• 2021

본 연구는 오토클레이브 양생시편이 예상과 달리 초기강도는 잘 발현되지 않는 반면, 수중에 장기 침지할 경우 압축강도가 향상되는 현상을 규명하기 위해 시작되었다. 증류수 및 알칼리 용액에 침지하였고, 세 가지 양생방법이 시도되었다. 알칼리용액에 침지할 경우 증류수 침지 시편이 추가적인 지오폴리머 반응에 의해 보다 더 높은 압축강도를 가질 것으로 예상하였으나, 실제로 추가적인 지오폴리머 반응에 의해 생성된 결정립들과 알칼리골재 반응에 의한 시편의 팽창 때문에 21일 침지 후 침지용액에 의한 압축강도의 변화는 크게 나타나지 않은 것으로 사료되었다. 지오폴리머의 수중 및 알칼리용액 내 장기공용성을 확보하기 위해서는 오토클레이브를 이용하여 양생 후 21일 이상 수중 침지를 시키면서 숙성(aging) 시키는 것이 바람직 한 것으로 결론지을 수 있었다.

• 한국건축시공학회지
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• 제2권4호
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• pp.169-176
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment, cold weather environment of curing temperature $5^{\circ}C$. Flash concrete tested slump, air contest, setting and Hardening concrete valuated setting period of form, day of age 3, 7, 28 compression strength in sealing curing. Underwater curing specimen compression strength of age 3. 7, 28day used strength change accordingly fly-ash concrete curing temperature. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Setting test result, fly-ash ratio of replacement higher delay totting time. Same volume of fly-ash ratio of replacement is lower fly-ash ratio of replacement fine aggregate delay setting time. Setting test in curing temperature $35^{\circ}C$ over twice fast setting in curing temperature $20^{\circ}C$ and all specimen setting delay in curing temperature $5^{\circ}C$. F40 specimen end of setting about 30 time. (2) Experiment result age 28day compression strength more fisher plan concrete then standard environment in curing temperature $20^{\circ}C$, cold weather environment in curing temperature $5^{\circ}C$, most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$ replacement binder 25%, fine aggregate 15%. (3) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.533-536
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• 2003

The objective of in this study makes investigation into the characteristics of antiwashout underwater concrete as to mix proportion, casting and curing water through experimental researches. in this study, sea sand is blended with river sand, crushed sand is blended with river sand and sea sand as to investigate the quality change and characteristics of antiwashout underwater concrete with variation of blend ratio of sea sand and crushed sand(0, 20, 40, 60, 80, 100%). Higher compressive strength is measured following the order of river sand, sea sand, crushed sand regardless of age and casting condition. Except for case of using river sand, blended ratio of 40% is appeared on most compressive strength.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 춘계학술대회
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• pp.216-217
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• 2015

알칼리 활성 슬래그 결합재의 초기 보양과 양생조건에 따른 강도발현 특성을 파악하고자 활성화제의 종류와 조합을 달리한 3가지 결합재를 초기 보양과 서로 다른 조건으로 양생시킨 후 강도를 측정하였다. 실험결과 3가지 결합재는 초기 보양 여부와 양생조건에 따라 다른 결과를 나타냈으며, 이는 모르타르의 경화속도와 공극수에 이온화된 활성화제의 음이온의 역할이 지배적인 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.427-432
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• 2001

In this study, crushed sand is blended with river sand and sea sand, to investigate the quality change of antiwashout underwater concrete with variation of blend ratio of crushed sand(0%, 20%, 40%, 60%, 80%, 100%). To see experiment conclusion, the more blend ratio of crushed sand increases, the more unit weight increases. Because the for that specific gravity of crushed sand is higher comparatively than that of river sand and sea sand. Higher compressive strength is measured following the order of river sand, crushed sand, sea sand regardless of age and casting-curing condition. Except for case of using river sand, blend ratio of 40% is appeared on most compressive strength. So the optimum blend ratio of crushed sand is 40% from the view point of compressive strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.1077-1080
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• 2003

High reactivity metakaolin (HRM) is a manufactured pozzolan produced by thermal processing of purified kaolinitic clay. Field performance and laboratory research of concrete containing HRM have demonstrated its value for bridge decks, bridge deck overlays, high-strength concrete and masonry products. This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing HRM, such as pH value, suspended solids, slump flow, and compressive strength. There were not much variations of pH value with the changing HRM contents, but suspended solid test showed that the amount of suspended solids of AWC with 10 and 20% of HRM were reduced in comparison with plain. Due to the fast hydration and reaction property of HRM, slump flow was decreased with increasing HRM contents. According to the results of compressive strength test, AWC with 10 and 20% of HRM showed higher strength characteristic than plain at all curing ages.