• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.335-340
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• 1997

The mineral admixtures, ground granulated blast furnace slag (GSB) and fly ash (FA), were mixed with ordinary portland cement(OPC) in order to reduce temperature rise and slump loss in concrete. In according to concrete replaced with 30% of GBS, the compressive strength of that developed to 574 kg/$\textrm{cm}^2$ at age of 28days and maximum temperature decreased to the extent of $5^{\cire}C$. When GBS and FA are mixed with concrete, it can be estimated that mix proportions of them have to be taken into consideration.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.21-25
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• 1991

For the purpose of improving the compressive strength of concrete, the high strength concrete which have the compressive strength about 800kg/$\textrm{cm}^2$ were made by using silica fume and high range water reducing admixture on reducing the water-cement ratio. But the facts that the slump loss of high strength concrete was high and the tensile strength and elastic modulus were not improved enough are indicated to problems which must be solved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.181-184
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• 2004

The objective of this experimental study is to grasp the effect of replacement level of high-quality recycled aggregate on the properties of high-performance concrete. The mixing types were divided into two series based on containing $0\%\;and\;15\%$ fly-ash. Replacement level of recycled aggregate ranged from $0\%\;to\;100\%$. Test results showed that the initial slump and the fluid velocity were independent on the replacement level of recycled aggregate, and the loss of compressive strength was almost $20\%$ with the recycled aggregate only.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.561-564
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• 2006

This study is aimed for investigating the engineering properties of concrete containing fly ash, slag powder and limestone powder. The results of this study are as follows; As limestone powder is incresed, slump, air loss and strength is reduced, variation ratio of length is reduced, dynamic modulus of elasticity and neutralization depth is incresed.

• 한국농공학회지
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• 제26권3호
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• pp.68-80
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• 1984

This study was attempted in order to investigate the effects of superplasticizers on fresh and hardened concrete. The experimental program included tests on the slump and slump loss, bleeding, time of set, air content, the compacting, factor Vee Dee, compressive strength, tensile and flexural strength, permeability, shrinkage and freege-thaw durability. The major conclusions that can be drawn on the study are as follows. 1. Superplasticizers were observed to have an appreciable fluidifying action in fresh concrete so that tinder appropriate conditions, they either considerably improved its workability or permitted a water reduction of at least 8-12% to be made while maintaining normal workability. 2. The bleeding ratios of base and S,P. Concrete were much lower than those of the conventional concrete. Differences between the base and S.P. Concrete were insignifician. 3. The setting time was the longest for conventionla concrete, followed by S.P. concrete and base concrete in thatorder. And AE water reduction admixtures showed an appreciable influence on the setting and hardening characteristics of concrete and prolonged the stiffening times. 4. The high initial slump values of S.P. concrete generally decreased rapidly with increased standing time. CF values showed increasing tendencies with the increase of S.P. content, and excessive addition of S.P. caused the segregation of fresh concrete, resulting in its rejection. 5. Though there was a slight increase in strength, no significant differences are observed between base and S.P. concrete in terms of the compressive, tensile and flexural strength. 6. The permeability of S.P. concrete was significantly less than that of the conventional concrete, and the shrinkage of S.P. concrete was considerably smaller than that of the conventional concrete, but there were no significant differences between base and S.P. concrete. 7. Compared to base concrete, S.P. concrete without entrained air tended to slightly increase freeze-thaw durability, and S.P. concrete with an appropriate entrained air gave satisfactory resistance to freezing and thawing.

• 한국산업융합학회 논문집
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• 제5권3호
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• pp.225-232
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• 2002

The purpose of this study is to find the mechanical properties of lightweight concrete using expanded clay. Thus, slump, air content, compressive strength, elastic modulus, tensile strength, length change ratio, unitweight change ratio and absorption of lightweight concrete have been investigated. The conclusions of this study are as follows ; 1. The loss of slump and air content of concrete increased as the expanded clay content increased and the size of coarse aggregate decreased. 2. The compressive strength of concrete using 100% expanded clay of 13, 19mm size at 28 days were respectively 282, $252kgf/cm^2$. 3. The elastic modulus and tensile strength of concrete decreased with increase of expanded clay content. 4. The length change ratio of concrete increased with the larger coarse aggregate size, and decreased with the increase of expanded clay content. 5. The unit weight of concrete decreased with the increase of expanded clay content, and the ratio of that was larger at the early age.

• 한국결정성장학회지
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• 제27권4호
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• pp.173-177
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• 2017

PNS 감수제와 시멘트 페이스트의 유동성의 관계를 평가하기 위해 물시멘트비 35 %에 PNS의 감수제 첨가하여 세 가지 시멘트에 대해 평가하였다. 세 가지 시멘트의 화학적 성질은 XRD, XRF로 평가하고, 물시멘트비 33 %인 콘크리트에 대한 $Na_2SO_4$의 첨가 효과는 압축강도, 슬럼프, 공기 함량의 측정에 의해 평가하였다. 실험 결과는 시멘트 A 및 C에 황산나트륨 2.6 %를 첨가하면 슬럼프 손실이 개선됨을 보여 주었으며, 시멘트 E의 경우 황산나트륨 1.3 % 첨가가 효과적이었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.23-26
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• 2006

The study about the concrete to use recently a light weight aggregate, processed actively. And concrete pumping with a high pressure pump has been popularized, the mechanical development, such as high pressure pumps or pipes, is progressing rapidly. Concrete placing by pumping has the advantage of the reduction of the construction period with workability, easiness of work and the increase of placing, but the quality variation of concrete is caused by pumping is seldom considered, including the increase of the pipe length by high-rising and large-sizing, there by the loss of the unit quantity of water, with pumpability or workability deteriorated. In this research, we will compare and analyze before pumping and after pumping samples of ready-mixed light weight concrete. The result of study as follow. The case of a light weight concrete which the low slump is more decrement compared with high slump light weight concrete in after pumping samples. After pumping the water by pressure of a pump was absorbed to the aggregate inside, and it showed an increase of compression strength about $5{\sim}20%$.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.601-604
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• 2008

본 연구에서는 FA의 치환율을 20 % 까지 증가시킨 콘크리트의 초기강도 증진 등 품질향상을 목적으로 새롭게 개발한 혼화제(이하 개발혼화제: 기호 G), 조강제, 수산화칼슘｛Ca(OH)$_2$｝및 미분시멘트 등을 사용하여 그 다량활용 가능성을 검토하였는데, 그 결과를 요약하면 다음과 같다. 혼합재료 종류별 슬럼프 로스는 Plain보다 조강제및 Ca(OH)2가 감소폭이 작게 나타나 개선된 결과치를 나타내었고, 미분시멘트와 G 혼화제는 슬럼프 로스가 크게나타났다. 공기량은 모든 혼합재료에서 모두 목표공기량을 만족하는 것으로 나타났다. 혼합재료 종류별 콘크리트의 압축강도는 조기 강도에서 G 혼화제가 재령 3일, 7일, 28일 모두 가장 크게 나타났고, 미분시멘트 및 조강제는 재령 3일 강도가 Plain보다 높은 강도증가율을 보였지만 재령이 증가하면 강도증가는 점차 둔화되는 것으로 나타났으며, Ca(OH)$_2$는 거의 효과가 없었다.

• 공업화학
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• 제16권6호
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• pp.815-821
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• 2005

현재 콘크리트 산업에서 주로 사용되고 있는 3가지 화학 혼화제로서 변경 리그닌계(LS), 나프탈렌계(SNF) 및 멜라민계(SMF) 혼화제가 널리 사용되고 있다. 본 연구에서는 SMF계 고유동화제의 합성과정을 수산화메틸화 반응(Hydroxymethylation)-술폰화 반응(Sulfonation)-중합(Polymerization)-중화(Neutralization) 및 안정화(Stabilization)의 4단계로 나누어 반응을 진행시키면서 멜라민과 포르말린의 몰비를 변화시키고, 반응 3단계 중합과정에서 산촉매의 종류와 양을 조절하면서 시멘트용 고유동화제를 합성하였다. 다양한 합성조건에서 합성된 SMF계 고유동화제를 시멘트 모르타르 및 페이스트에 적용하여 작업성, 슬럼프 손실 및 압축 강도 등의 물리적 특성을 비교하였고, SEM image를 통하여 수화물 형태를 관찰하였다. 실험결과 SMF 고유동화제의 축합물 구조특성이 시멘트의 유동화 특성에 큰 영향을 주었다.