• Journal of the Korea Institute of Building Construction
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• v.21 no.2
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• pp.97-104
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• 2021

This study aims to develop non-sintered cement that can replace the Portland cement by utilizing industrial by-products. As a suggestion, the physical properties of non-sintered cement mortar depending on the curing method were investigated with ground granulated blast furnace slag, class C fly ash, and class F fly ash. As a result of the study, it was found that the strength performance and absorption rate were improved through the heat treatment process after steam curing. It was confirmed through crystal phase analysis that the hydration was accelerated after heat treatment, and the bonding material formed a dense internal structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.125-132
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• 2015

This paper presents an experimental investigation in order to evaluate fresh and hardened properties of LP (Limestone Powder) blended cement concrete. The cement contents of the mixtures are replaced by LP in the range of 10%, 15%, 25%, and 35%, while a control mixture is prepared with only OPC (Ordinary Portland Cement). The fresh concrete properties like slump and air content are similar to those of control mixture up to 35% of replacement ratio of LP, however a delay in setting time is evaluated. The hardened properties including compressive strength, flexural strength, and rapid freezing and thawing resistance shows similar results of control mixture up to 15% of replacement. Relatively lower strength development is evaluated over 25% replacement of LP. For accelerated carbonation test, resistance to carbonation rapidly decreases with increasing LP replacement ratio due to the limited amount of $Ca(OH)_2$. From the study, LP replacement under 15% can be adopted considering reduction of strength and resistance to carbonation.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.164-170
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• 2002

Effect of the polymer-binder ratio and slag content on the properties of combined wet/dry-cured polymer-modified mortars using granulated blast-furnace slag are examined. Results shows that the flexural and compressive strengths of polymer-modified mortar using the slag tend to increase with increasing slag content, and reaches a maximum at a slag content of 40 ％, and is inclined to increase with increasing polymer-binder ratio. Water absorption, carbonation depth and chloride ion penetration depth tend to decrease with increasing polymer-binder ratio and slag content. Accordingly, the incorporation of slag into polymer-modified mortars at a slag content of 40％ is recommended for a combined wet/dry curing regardless of the types of polymer.

• Journal of the Korea Institute of Building Construction
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• v.15 no.3
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• pp.257-263
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• 2015

In this study, the quality of blast furnace slag and the engineering properties of recycled aggregate based mortar with variable replacement of blast furnace slag have been focused. Blast furnace slag(BS) manufactured in various areas in Korea were prepared for this study. For the investigation results, 4 types(among the all of 9 types) of the experimental results were identified as below the standard level when using blast furnace slag chosen from different factories. Especially the particle size of the blast furnace slag was considered as the largest problem. When using BS in the recycled aggregates based mortar, the increase amount of blast furnace slag, increased the fluidity but delayed the setting time and decreased strength at early age. Based on the relationship of the amount of BS and the engineering properties of mortar, this study found that the amount of $SO_3$ and L.O.I affect the setting time, 3 days strength and 91 days strength to the certain standard level.

• Journal of the Korea Institute of Building Construction
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• v.16 no.4
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• pp.321-329
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• 2016

The use of ternary blended cement consisting of Portland cement, granulated blast-furnace slag (GGBFS) and fly ash has been on the rise to improve marine concrete structure's resistance to chloride attack. Therefore, this study attempted to investigate changes in chloride attack resistibility of concrete through NT Build 492-based chloride migration experiments and test of concrete's ability to resist chloride ion penetration under ASTM C 1202(KS F 2271) when 1.5-2.0% of alkali-sulfate activator (modified alkali sulfate type) was added to the ternary blended cement mixtures (40% ordinary Portland cement + 40% GGBFS + 20% fly ash). Then, the results found the followings: Even though the slump for the plain concrete slightly declined depending on the use of the alkali-sulfate activator, compressive strength from day 2 to day 7 improved by 17-42%. In addition, the coefficient from non-steady-state migration experiments for the plain concrete measured at day 28 decreased by 36-56% depending on the use of alkali-sulfate. Furthermore, total charge passed according to the test for electrical indication of concrete's ability to resist chloride ion penetration decreased by 33-62% at day 7 and by 31-48% at day 28. As confirmed in previous studies, reactivity in the GGBFS and fly ash improved because of alkali activation. As a result, concrete strength increased due to reduced total porosity.

• Cement
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• s.76
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• pp.51-56
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• 1979

F.L.Smidth는 기획적인 규모로 광범위한 시험과 운용을 한 후에 신형의 크리카 밀을 개발했다. 이 밀의 미분쇄실에서는 평균 단위중량이 5$\~$7g 밖에 안되는 최적 크기의 분쇄매체가 사용된다. 이의 사용은 특수하게 설계된 밀의 출구와 전연 새로운 원리에 바탕을 둔 매우 효율적인 스크리닝 diaphragm에 의해서 가능하게 되었다. Conbidan 밀은 개회로나 폐회로식 분쇄에서 모두 최저의 분쇄 효율을 보장하기 때문에 에너지 소비량이 상당히 절감된다. 완성시멘트에서 요구되는 입도에 따라서, 그리고 채택된 분쇄방법에 따라서 Conbidan 밀의 분쇄 효율은 (kg/kwh), 기업적인 규모로 장기에 걸쳐 시험한 결과로 나타난 바와 같이, $12\%\~27\%$가 향상된다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.113-117
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• 2009

Fly ash (called FA hereafter) that results from thermal power plants is a long-term strength improving substance with reactivity to pozzolan and has been used for long. However, large amount of FA shows many advantages such as reduction of hydratio energy, long-term improvement in strength and economic feasibility and also has difficulties from reduction in initial strength and durability. In a preceding study, fine particle cement was applied to test the effects on initial strength. Therefore in this study, the effects of fine particle cement on the quality of FA concrete were reviewed. The results can be summarized as follows. Liquidity was increased by the most at FC substitution ratio of 15%. Air capacity was reduced according to increasing substitution ratio of FA and FC. Compressive strength showed high strength expression at all ages when FC was substituted at 45%. Synthesizing the above results, appropriate mixing of FC in FA concrete can improve liquidity, reduce unit quantity and show improvement in strength. In particular, mixed use of FC seems effective in improving early quality of concrete.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.150-151
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• 2009

수화성이 회복된 미분말에 시멘트를 10% 첨가하고 무수규산을 20 wt% 배합하여 제작한고화체가 방사성 고화체 압축강도 인수기준에 만족함과 동시에 부피증가를 최소로 할 수 있었고이 조건으로 ANS 16.1 방법에 준하여 고화체 침출 실험이 진행 중에 있다. 고화체의 압축강도 및 침출지수 모두 처분장 인수 기준에 만족할 경우 콘크리트 미분말 폐기물의 부피 증가를 최소화함은 물론 안정한 상태로 처분할 수 있을 것으로 예상된다.

• Land and Housing Review
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• v.14 no.4
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• pp.121-129
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• 2023

In this study, we attempted to reduce CO₂ generated during manufacturing by replacing limestone (CaCO₃), a carbonate mineral used to produce cement clinker, with a decarbonated raw material to which CO₂ is not bound. The raw material for decarbonization was cement paste attached to waste concrete, among various industrial by-products. Waste concrete has cement paste adhered to the aggregate, which cannot be separated efficiently by general crushing and grinding methods. Peeling and grinding methods effectively remove only the cement paste without damaging the original aggregate. The abrasion time, steel ball type, and steel ball ratio were selected as effective factors for Abrasion. An optimal abrasion experiment was conducted to produce waste concrete fine powder containing decarbonated CaO as a cement clinker raw material through an experimental design method. The experiment revealed that the optimal conditions for producing waste concrete fine powder were an abrasion time of 7 minutes, a steel ball size for pulverization of 8 mm, and a steel ball ratio for pulverization of 0.6.

• Resources Recycling
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• v.19 no.6
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• pp.86-92
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• 2010

In the many kind of construct-material, the concrete which has the high-strength and a durability is sufficient to use with structure-material. but the color of concrete is very monotony, so generally concrete isn't used the out surface. although color concrete is a method of expressing surface, the combination of pigment and cement cause many physical problem such as efflorescence phenomenon, strength degradation and so on. In this study, It attempt to develop the black mortar using the industrial granulated blast furnace slag and to evaluate basic physical properties compare with general color concrete to solve the color concrete problem. The result of experiment showed that the flow dropped mixing of pigment. but flow increased in proportion to the mixing rate in occasion of mortar that mix granulated blast furnace sla and black mortar which was made granulated blast furnace slag has more visible black color than any mortar.