• Computers and Concrete
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• 제21권2호
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• pp.139-147
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• 2018

Due to enhanced construction requirement, ready mixed concrete are being popular day by day. The current study aimed to develop ready mixed concrete using GBFS contained cement and determine its properties of fresh and hardened states. A real scale experiment was set up in a ready mixed plant for measuring workability and compressive strength. The workability was tested after mixing (within 5 minutes), 30, 60, 90, 120 and 150 minutes of the running of bulk carrier. The ready mixed carrier employed spinning motion i.e., rotating around its axis with 20 RPM and running on road with 1km/h speed. The mixing ratio of cement: sand:gravel, water to cement ratio, super plasticizer were, 1:1.73:2.47, 0.40 and 6% of cement, respectively. The chemical composition of raw material was determined using XRF and the properties of cements were measured according to ASTM standards. The experimental results confirm that the cement with composition of 6.89% of GBFS, 4% of Gypsum and 89.11% of clinker showed the good compressive strength and workability of concrete after 150 minutes of the spinning motion in bulk carrier.

• Advances in concrete construction
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• 제13권3호
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• pp.233-242
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• 2022

An attempt is made to develop an eco-friendly concrete with ground granulated blast furnace slag (GGBS) and pond ash as partial replacement materials for cement and fine aggregate, respectively without compromising the strength and durability. Sixteen concrete mixes were developed by replacing cement and fine aggregate by GGBS and pond ash, respectively in stages of 10%. The maximum replacement levels of cement and fine aggregates were 50% and 30% respectively. Experimental results revealed that the optimum percentage of GGBS and pond ash replacement levels were 30% and 20% respectively. The optimized mix was used further to study the flexural behavior and durability properties. Reinforced Concrete (RC) beams were cast and tested under a four-point bending configuration. Also, the specimens prepared from the optimized mix were subjected to alternate wet and dry cycles of acid (3.5% HCl and H₂SO₄) and sulphate (10% MgSO₄) solutions. Results show that the optimized concrete mix with GGBS and pond ash had a negligible weight loss and strength reduction.

• Computers and Concrete
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• 제31권6호
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• pp.545-559
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• 2023

In this study, an experimental investigation was conducted to assess the influence of ground granulated blast furnace slag (GGBS) and silica fume (SF) on the fresh and hardened properties of grout specimens and preplaced aggregate concrete (PAC). Grout proportions were optimized statistically using a factorial design and were applied to 10 mm and 20 mm coarse aggregates to produce PAC. The results demonstrate that GGBS has a more significant effect on the compressive strength of grout compared to SF, with a small increase or decrease in the GGBS content having a greater influence on the compressive strength of grout than SF. The water to binder ratio had the most significant effect on the compressive strength of PAC, followed by the coarse aggregate size and sand to binder ratio. An empirical relationship to predict the compressive strength of PAC was proposed through an experimentally derived factorial design along with a statistical analysis of collectively obtained data and a deep literature review. The results predicted by the empirical relationship were in good agreement with those of PAC produced for verification.

• 한국세라믹학회지
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• 제14권2호
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• pp.88-94
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• 1977

Zircon sand of two different particle distribution with 2 percent of ground pyrophyllite were adoted to prepare the dense specimens of the stopper nozzle for the tundish. The molding pressure of $600kg/cm^2$ brought about the superior properties to those obtained t the pressure of $300kg/cm^2$, and as the firing temperatures were increased from $1, 350^{\circ}C$ to $1, 600^{\circ}C$, the better characteristics resulted. The addition of 2 percent $MgCr_2O_4$ to zircon pyrophyllite batch was more effective in corrosion-resistance to the blast furnace-slag.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.235-236
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• 2011

This study analyzed flowing and strength properties of mortar depending to fine aggregate types and replacement ratio by using blast furnace slag, red mud, and silica fume that are industrial by products. The findings showed that higher replacement level of fine aggregate increased air content while decreased table flow. In addition, compressive strength showed that the higher replacement level was regardless of fine aggregate types, the lower strength became. Mortar substituted by the dredged sand showed high strength.

• 한국지반공학회논문집
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• 제26권3호
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• pp.5-12
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• 2010

본 연구에서는 지진후의 침하에 미치는 반복 전단방향의 영향을 명확히 하기 위해， 일본의 표준사인 Toyoura sand와 천연모래인 Genkai sand 및 고로수쇄슬래그(GBFS)에 대해서 다축(다방향) 전단실험을 수행하였다. 공시체는 높이 75mm, 직경 20mm이다. 일련의 실험에서, 변형률 반복 재하회수 n=5, 20, 30, 100, 200회로 변화시켜 행하였으며, 전단변형률 진폭은 0.1%에서 1.0%까지 변화시켰다. 각 공시체의 상대밀도는 50, 60, 70%를 대상으로 하였다. Toyoura sand와 고로수쇄슬래그에 대한 실험결과로부터, 반복전단후의 침하는 상대밀도가 작을수록 크게 되며, 전단변형률 진폭의 증가와 더불어 크게 나타났다. 반복전단 방향의 차이에 따른 영향이 감소한 후에 Toyoura sand의 전단후의 침하는 일정치에 수렴하지만, 고로수쇄슬래그는 반복전단회수의 증가와 더불어 증가되었다. 또한, 반복전단후의 침하는 Kaolinite > Toyoura sand > Genkai sand > GBFS의 순으로 나타났다.

• 한국세라믹학회지
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• 제17권1호
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• pp.27-34
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• 1980

The synthesis of glass-ceramic materials from glasses based on industrial wastes or natural rocks their physical properties were studied. Glasses of composition, CaO14.7∼16.1, MgO7.4∼9.0, Al2O38.3∼19.3, SiO2 48.9∼51.0wt% were prepared from domestic blast furnace slag, serpentine, sea sand and etc. with additions of chromic oxide, and fluoride as nucleating agent. The glasses were subjected to controlled heat treatments and yielded fine microstructure of glass-ceramics which were composed of monocrystalline phase of aluminous diopside. X-ray diffraction techniques were adopted to identify the crystalline phases and to determine the degree of crystallization quantitatively. Density, coefficient of thermal expansion, young's modulus, microhardness and modulus of rupture were measured and the resulting properties were discussed in terms of the heat-treatment conditions, the degree of crystallization, species of crystaline phase, the microstructures formed in glass-cramics and the chemical compositions of mother glasses.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.389-392
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• 2008

철강 산업에서 발생되는 슬래그 부산물 중 전기로슬래그는 슬래그 자체의 팽창반응성으로 인해 콘크리트용 원자재로서 활용이 불가능하지만, 슬래그의 팽창반응성을 제거한 전기로산화슬래그는 콘크리트용 골재로서 활용이 가능하다. 본 연구에서는 산화 전기로슬래그 잔골재를 사용한 콘크리트의 기초품질 특성을 검토한 것으로서, 산화 전기로슬래그 잔골재는 입형이 둥근 풍쇄전기로슬래그 및 입형이 부순모래와 유사한 파쇄 전기로슬래그 잔골재가 있으며, 본 실험에서는 파쇄 전기로슬래그 잔골재를 사용하였다. 잔골재에 대해 용적 대체한 경우에서의 콘크리트의 품질 특성을 검토 결과, 전기로슬래그 잔골재는 골재 자체의 밀도가 일반 천연골재에 비해 매우 높고, 흡수율이 매우 낮기 때문에 전기로슬래그 잔골재 대체율이 증가할수록 동일 유동성을 확보하는 단위수량은 감소하는 경향을 나타내고 있으며, 동일 단위수량 적용시에도 콘크리트의 강도 발현 특성은 증가하는 경향을 나타내고 있다.

• 콘크리트학회논문집
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• 제26권5호
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• pp.607-614
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• 2014

본 논문에서는 품질확보를 위하여 혼합골재 입도분포를 적용한 부순모래 숏크리트에 플라이애시, 고로슬래그 미분말, 메타카올린, 실리카퓸을 종류 및 혼입률에 변동을 주어 혼입하여 숏크리트의 기초특성과 내구특성에 미치는 영향을 고찰하였다. 또한 각 혼화재료의 주요 혼입률을 선정하고 실제 숏팅을 실시 하여 숏팅 전 후의 기초특성과 내구특성을 분석하였다. 실내실험 결과 광물성 혼화재료 혼입률이 증가할수록 압축강도가 증가하는 경향을 보였다. 특히 메타카올린을 혼입한 경우 가장 우수한 강도 증진효과를 보였으며, 숏팅 후 압축강도 역시 코어링에 의한 강도감소 현상을 감안하여도 강도 발현이 우수한 혼화재료로 판단된다. 염소이온 침투저항성 시험과 황산저항성 시험 결과 광물성 혼화재료 혼입은 염소이온과 황산에 대한 저항성이 증진되는 경향을 보인다. 화상분석을 통한 공극구조 분석 결과 공기연행제를 사용하지 않아 소요의 간격계수와 비표면적을 얻는데 실패하였으며, 향후 공기연행제의 도입 후 실험이 진행될 필요성을 보이고 있다.

• Advances in concrete construction
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• 제5권3호
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• pp.183-199
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• 2017

This paper reports an experimental study into the rheological behaviour of Smart Dynamic Concrete (SDC). The investigation is aimed at quantifying the effect of the varying amount of mineral admixtures on the rheology, setting time and compressive strength of SDC containing natural sand and crushed sand. Ordinary Portland cement (OPC) in conjunction with the mineral admixtures was used in different replacement ratio keeping the mix paste volume (35%) and water binder ratio (0.4) constant at controlled laboratory atmospheric temperature ($33^{\circ}C$ to $35^{\circ}C$). The results show that the properties and amount of fine aggregate have a strong influence on the admixture demand for similar initial workability, i.e., flow. The large amounts of fines and lower value of fineness modulus (FM) of natural sand primarily increases the yield stress of the SDC. The mineral admixtures at various replacement ratios strongly contribute to the yield stress and plastic viscosity of SDC due to inter particle friction and cohesion.