• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.239-240
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• 2023

In this study, concrete pumpability was investigated using a sliding pipe rheometer when the slump was different, and the cause was analyzed by comparing the actual field pump pressure. As a result of the experiment, it was found that the concrete pumpability was greatly affected by the slump measurement value.

• 한국세라믹학회지
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• 제44권8호
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• pp.430-436
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• 2007

Rheological properties of cement paste containing ultrafine blastfurnace slag (UBS, $9600cm^2/g$) were investigated by mini-slump test, pH meter, conduction calorimeter and coaxial cylinder viscometer. In order to improve rheological properties of the cement paste, granulated blastfurnace slag (GBS, $3500cm^2/g$) and polycarboxylate type superplasticizer (PC) were also used in this experiment. The fluidity of cement paste containing UBS was decreased. The yield stress and plastic viscosity of cement paste was increased with increasing UBS. But the rheological properties were improved when GBS and PC were added to UBS blended cement paste. In the relationship between the yield stress and the plastic viscosity or the mini-slump value, the yield stress of the cement paste was proportional to the plastic viscosity of it. However the cement paste mini-slump value was in inverse proportional to the yield stress.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.489-494
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• 2001

Several studies have reported that Granulated Blast-Furnace Slag improved the properties of concrete. The Granulated Blast-Furnace Slag could be a good alternative in the shortage of aggregate situation. Slag shows the possibility of influential aggregate and effect of environment preservation. This study presents that the basic properties of fresh concrete using Air-cooled Blast-furnace slag aggregate and Water-cooled Blast-furnace slag aggregate. Testing Factors of this study are concrete slump, slump loss, bleeding, and air contents. The result of this study is below. 1) In case of proportion slag and grave is 50 to 50, the biggest slump value is measured. 2) In the concrete using of air-cooled Blast-furnace slag aggregate, the bleeding capacity is a little. In the concrete using of Water-cooled Blast-furnace slag aggregate, the bleeding capacity goes up to 50% increase. 3) As substitution rate of the granulated blast-furnace slag goes up, air content is increased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.219-222
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• 1999

Concrete is to be important quality in placement point and exact test method needed about early judgement method concrete on placement point. But early judgement method of concrete proposed various kind of method because the problems of accuracy and the time required of test exists, it is used within the limits. This study is to propose of early strength judgement by using microwave for accurate estimating early strength of concrete and to develop test machine. Through out this study we find that belows. 1) Strength development of concrete specimen according to the time heated by microwave showed the height strength development in 9 minutes regardless of slump and w/c. 2) As cooling time is long, strength of concrete specimen according to the time heated by microwave showed high strength development and this tendency is like regardless of heating time, w/c and slump. 3) As w/c is high, accelerating strength development according to w/c showed lower strength development and this tendency is like regardless of slump, heating time and cooling time. 4) As slump is big, compressive strength of specimen in standard curing showed lower value and as w/c is big, strength development showed lower

• 한국지반공학회논문집
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• 제25권2호
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• pp.17-24
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• 2009

일반적으로 점토의 비 배수전단강도 산정은 실내실험을 통해 구하지만 초연약점토의 경우 재료의 특성 상 실내실험이 어렵고, 현장실험 또한 여러 제약조건들을 감수해야 한다. 따라서 본 논문에서는 실내에서 수행한 물성실험 및 슬럼프실험과 실내 베인 전단실험의 결과를 회귀분석을 통해 슬럼프 값과 비 배수전단강도 사이의 상관 관계식을 도출하였다. 도출된 상관 관계식의 신뢰성 확보를 위하여 t-분포를 이용한 통계분석을 실시하였고 현장의 데이터와 비교 분석하여 관계식의 적용성 및 신뢰성을 확보하였다.

• 한국지반환경공학회 논문집
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• 제11권10호
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• pp.5-13
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• 2010

저유동성 몰탈주입은 구조물기초의 보강이나 연약지반 개량 등에 폭넓게 쓰이고 있으며, 작업 공간이 협소한 경우도 주변여건에 크게 구속받지 않고 시공할 수 있는 등 매우 유리한 특징을 가지고 있다. 그러나 현재 저유동성 몰탈주입공법의 설계단계에서 적용할 수 있는 개량효과 및 영향 반경에 대한 예측방법과 이에 대한 검증이 이루어지지 않아 지반보강공법으로써의 다양한 적용을 위하여 이에 대한 정립이 필요하다. 본 연구에서는 매립토층에서 저유동성 몰탈주입 후 현장시험을 실시하여 주입에 의한 지반개량효과를 확인하고, 이를 기존의 제안된 개량효과에 대한 이론식으로 계산된 값과 비교함으로써 이론식의 적용성을 평가하고자 하였다. 연구결과, 저유동성 몰탈주입에 의해 개량효과가 매우 우수함을 확인할 수 있었으며, 이를 기존의 이론식과 비교한 결과 서로 유사한 결과를 나타내어 연구대상 현장과 유사한 느슨한 사질토의 경우 기존의 이론식은 적용성이 양호한 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.501-506
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• 1998

This paper is an experimental study on the flexural strength and ductility capacity of reinforced high performance concrete beams with the concrete which has compressive strength of 600~700kg/$\textrm{cm}^2$, slump value of 20~25cm and slump-flow value of 60~70cm. Total 8 beams with different tensile reinforcement ratio and pattern of loading were tested. Form the results of reinforced high performance concrete beams, the equivalent stress block parameters proposed by MacGregor et al. or New Zealand code are recommended to use. Also, an extreme fiber concrete compressive strain of reinforced high performance concrete beams are distributed 0.0033~0.0048. In reinforced high performance concrete beams, reinforcement ratio in order to insure curvature ductility index 2 and 4 propose by ACI code should be less than those of reinforced normal strength concrete beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.197-202
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• 1999

The properties of surface-glossing of exposed concrete with the kinds of form materials and form oil are investigated under various slump value. According to the experimental results, surface-glossing has high value with the increase of slump. In case of surface-glossing with the kind of the form, the form made of acryl has the best performance among the form kinds tested in this experiment. The order of surface-glossing is follows ; fancy plywood > metal form > plywood. Water solution type form oil has better performance in surface-glossing than oil solution type form oil. Also, surface-glossing get worse with the elapse of age.

• 자원리싸이클링
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• 제10권2호
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• pp.41-49
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• 2001

본 논문은 여주, 이천 등지의 도자기 공장지대에서 다량으로 발생되는 폐도자기를 파쇄하여 콘크리트용 골재로 사용 가능한지에 대해 알아보기 위하여 실험을 실시한 결과를 정리한 내용이다. 실험방법으로써는 요업폐기물을 파쇄하여 크기에 따라 콘크리트용 잔골재와 굵은골재로 분류한 후 대체율을 달리하여 모르터 및 콘크리트를 제조하여 유동성 및 재령별 압축강도 등 콘크리트의 기초적 성질에 대하여 고찰하였다 실험결과, 요업폐기물을 잔골재로 사용한 모르터의 경우, 강모래만을 사용한 모르터보다 대체율에 관계없이 플로우 값 및 압축강도가 향상됨을 알 수 있었다 한편 콘크리트용으로 요업폐기물 잔골재로 대체한 콘크리트의 경우 슬림프 값이 저하하는 문제점이 나타났으나, 압축강도의 경우 요업폐기물을 잔골재로 사용한 콘크리트는 초기재령에서는 낮게 나타났으나 장기재령에서는 요업폐기물 골재를 사용하지 않은 경우와 거의 유사하거나 오히려 상회하는 좋은 결과를 얻을 수 있었다