• 한국세라믹학회지
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• 제55권1호
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• pp.61-66
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• 2018

In this study, fabrication method of inorganic insulation were studied to reduce $CO_2$ from buildings. Main materials for inorganic insulation were used cement, blast furnace slag and aluminum powder as foaming agent. Mixing ratio of cement and slag was controlled and physical properties of inorganic insulation were analyzed. When inorganic insulation was fabricated using cement and slag, expanded slurries were not sunken and hardened normally. Pore size was 0.5 - 2 mm; mean pore size was about 1mm in inorganic insulation. Compressive strength of inorganic insulation increased with curing time and increased slightly with cement fineness. However, specific gravity decreased slightly with curing time; this phenomenon was caused by evaporation of adsorptive water. When inorganic insulation was dried at $60^{\circ}C$, compressive strength was higher than that of undried insulation. The highest compressive strength was found with a mixture of cement (50%) and slag (30%) in inorganic insulation. Compressive strength was 0.32 MPa, thermal conductivity was 0.043 W/mK and specific gravity was $0.12g/cm^3$.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.467-472
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• 2000

It is known that chloride ion in concrete destroys the passive film of reinforcement inside concrete and accelerates corrosion which is the most influencing factor to durability of concrete structures. In this thesis, a chloride ion diffusion model for blast furnace slag(BFS) concrete, which has better resistance to both damage due to salt and chloride ion penetration than ordinary portland cement concrete, is proposed by modifying existing model of normal concrete. Proposed model is verified by comparing diffusion analysis results with both results by indoor chloride penetration test for specimens and field test results for actual RC bridge pier. Also, the optimum resistance condition to chloride penetration is obtained according to degrees of fineness and replacement ratios of BFS concrete. As a result, resistance to chloride ion penetration for BFS concrete is more affected by replacement ratio than degree of fineness.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.45-50
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• 1993

This paper describes some results of various tests which were carried out with varying the fineness of salg from 6000 to 10000$\textrm{cm}^2$/g and the slag content in cement from 30 to 50wt% for the perpose of utilizing finely ground blast-furnace slag as an ingredient for high-performance concrete. Test for heat of hydration, microstructural and hydration characteristics in paste, and fluidity and compressive strength in mortar were carried out. From these test results, it was found that, by properly determining the content and fineness of the slag, it is possible to manufacture high-performance concrete that has low heat of hydration, high early strength development, fine pore size and a highly densified microstructure.

• Computers and Concrete
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• 제20권4호
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• pp.381-389
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• 2017

The various types of structural materials that are available in the construction industry nowadays make it necessary to predict their stress-strain behavior. Geopolymer are alternatives for ordinary Portland cement concrete that are made from pozzolans activation. Due to relatively new material, many mechanical specifications of geopolymer are still not yet discovered. In this study, stress-strain behavior has been provided from experiments for unconfined geopolymers. Modulus of Elasticity and stress-strain behavior are critical requirements at analysis process and knowing complete stress-strain curve facilitates structural behavior assessment at nonlinear analysis for structures that have built with geopolymers. This study intends to investigate stress-strain behavior and modulus of elasticity from experimental data that belongs for geopolymers varying in fineness and mix design and curing method. For the sake of behavior determination, 54 types of geopolymer are used. Similar mix proportions are used for samples productions that have different fineness and curing approach. The results indicated that the compressive strength ranges between 7.7 MPa and 43.9 MPa at the age of 28 days curing.

• Computers and Concrete
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• 제21권6호
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• pp.705-715
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• 2018

This paper presents an experimentally investigation pertinent to the mechanical properties of rubberized mortar (RM) with styrene-butadiene rubber (SBR). The SBR were used with constant water-to-cement ratio of 0.485 and two different volume proportion of SBR particles were utilized as aggregates. One types of SBR particles with fineness modulus of 4.951 were utilized 0%, 10%, and 20% of aggregate volume. Effectiveness of SBR replacement ratio, curing and aging effect on the compressive strength, flexural strengths as well as load-displacement. Compressive and flexural strength of concrete were investigated at the end of 28-days and 56-days age. Obtained results demonstrated that utilization of SBR reduced the flexural strength of SBR mortar at the earlier curing age while SBR increased. Moreover, mechanical properties of mortar mentioned above were significantly affected by the water cure timing with an increasing proportion of the replacement level of SBR.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.313-319
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• 2017

일반적으로 플라이애시의 입도, 화학성분, 비정질양, 비정질 Si, Al 양등 매우 다양한 요인이 시멘트와의 반응에 영향을 미치고 있다. 본 연구에서는 플라이애시의 입자 특성이 압축강도에 미치는 영향을 확인하고자 한다. 표준사를 플라이애시와 유사한 입도로 분쇄하여 플라이애시와 동일하게 시멘트와 배합하여 압축강도를 측정하였다. 측정된 압축강도 결과 값을 사용하여 시멘트 수화반응에 의한 강도와 입자 충진 효과에 의한 강도 증진을 확인하였다. 표준사 분말을 치환한 모르타르의 압축강도 결과를 활용하여 플라이애시의 포졸란 반응에 의한 강도 증가분을 계산하였다. 이러한 결과 값과 플라이애시의 입자 특성을 비교한 결과, 분말도는 압축강도와 약한 상관성을 보이고 있으며, PI(Pozzolanic Index)는 10% 통과직경(D10)과 50% 통과직경(D50)과 좋은 상관관계를 나타내었다. 따라서 향후 PI와 D10과의 상관성은 플라이애시의 화학적 특성과 함께 플라이애시 특성을 파악하는 좋은 수단이 될 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.525-528
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• 2008

고에너지 소비형인 시멘트의 대체 재료로써 고로슬래그의 활용성을 높이기 위해 분쇄 방법과 입자의 분말도 그리고 알칼리 자극제의 종류에 따른 50wt.%의 고로슬래그를 치환한 고로 슬래그 시멘트의 수화 및 물리적 특성을 조사하였다. 알칼리 자극제로써 Ca(OH)$_2$, NaOH, Na$_2$SO$_4$,사용하였고 이런 특성들을 비교하기 위해 자극제를 넣지 않은 무첨가 슬래그 시멘트를 함께 실험하였다. 압축강도 실험에서의 분쇄방법에 차이로는 알칼리 자극제에 관계없이 롤러밀로 분쇄한 슬래그가 대체적으로 높은 강도를 나타내었으며 자극제에 따라서는 재령 7일 이내의 초기강도에서는 분말도와 분쇄방법에 관계없이 Na$_2$SO$_4$>Ca(OH)$_2$>None>NaOH 순으로 나왔으며 28일의 장기강도에선 Ca(OH)$_2$가 가장 높게 나타났다.

• 콘크리트학회지
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• 제10권4호
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• pp.195-204
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• 1998

콘크리트가 고강도를 확보하기 위해서는 일반적으로 큰 단위시멘트량 및 낮은 물-시멘트비를 유지해야 하므로 콘크리트 타설후 내부온도 상승은 필연적이며, 구조물의 위치와 온도응력차에 의하여 콘크리트 구조물에 균열이 발생하게 된다. 그러므로 고강도용 콘크리트의온도상승 억제대책의 한 방안으로 고로슬래그미분말 3종류와 혼합률 4단계로 변화시킨 콘크리트를 제조하여 온도상승량과 최고온도 도달시간 및 강도를 측정하였으며, 고로슬래그미분말을 5단계로 혼합한 페이스트의 수화발열량 및 수화속도를 측정한 값에 대하여 고찰하였다. 본 연구결과 고로슬래그미분말의 분말도 6,000$\textrm{cm}^2$/g, 혼합률 50% 정도인 고강도용 콘크리트가 온도상승 억제효과 뿐만 아니라 조기재령에서의 강도도 비교적 잘 만족하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.63-68
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• 1998

The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

• 콘크리트학회논문집
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• 제16권3호
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• pp.433-440
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• 2004

In order to improve the performance of concrete, generally, modern cements often incorporate several mineral admixtures. In this study, the experimental included the flow value, air content of mortar containing limestone powder and length change and compressive strength of mortar specimen immersed in sulfate solutions. From the experimental results, the limestone powder cement matrices improved the physical properties and sulfate resistance of cement matrices at $10\%$ replacement ratio of limestone powder. The $30\%$ replacement ratio of limestone powder was significantly deteriorated in sodium sulfate solution. Irrespective of fineness levels of limestone powder, length change and SDF of mortar specimens with only $10\%$ replacement was much superior to the other replacements.