• Title/Summary/Keyword: reduction slag

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An Experimental Study on Freezing-Thawing Resistance of Concrete Using Ground Granulated Blast-Furnace Slag (고로슬래그 미분말을 사용한 콘크리트의 동결융해 저항성에 대한 실험적 연구)

  • 남용혁;최세규;김동신;김생빈
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.148-153
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    • 1996
  • Concrete with ground granulated blast-furnace slag can be affected by frost attack because the reaction of hydration is slow at the early age. In this study, therefore, the freezing and thawing test has been carried out to investigate the freezing and thawing resistance on concrete with ground granulated blast-furnace slag. The freezing and thawing test has been performed on concrete a blended cement, which was substituted by ground granulated blast-furnace slag with 4 kinds of ratio (non-admixture, 20%, 40% and 60%). And also tested on concrete added the AE agents to the concrete of same mix proportion to search the improvement effects about the resistance. As a result, the freezing and thawing resistance showed a tendency of reduction in proportion to the increase of the substitution ratio. For non-AE concrete, resistances of the freezing and thawing were very poor as the durability index indicated less than 5.8%. For AE concrte, resistance of the freezing and thawing were excellent as the durability index indicated more than 80.9%.

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A Study on the Properties of Converter Slag Modified by Addition of Waste Foundry Sand (폐주물사를 첨가한 전로슬랙의 개질특성에 관한 연구)

  • 김영환;김종학;고인용
    • Resources Recycling
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    • v.8 no.1
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    • pp.44-51
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    • 1999
  • Converter slag was reduced and modified by the simultaneous addition of carbon and waste foundry sand as a $SiO_2$ source. The basic properties such as phase distribution, composition, specific density, hardness. absorption of water and compressive strength of modified slags were measured. The Iron recovery was significantly affected by the basicity of slag. The properties of slow cooled-modified slags of basicity 1.34 arc very similar to the natural aggregates.

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A Study on The Corrosion Resistance of Concrete Containing Copper Slag (동제련 슬래그 혼입 콘크리트의 부식 저항성에 관한 연구)

  • Lee, Dong-Un;Jung, Yoo-Jin;Kim, Young-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.5
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    • pp.189-196
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    • 2007
  • The purpose of this study was to analyze steel corrosion resistance of concrete containing copper slag. The specimens were made with normal portland cement and pozzolan materials with various replacement ratio and with W/B ratio ranging from 35% to 55%. Compressive strength, coefficient of chloride diffusion, corrosion area ratio and weight reduction ratio were determinated for the test. The results show that the concrete with pozzolan materials is superior resistant to chloride ions compared to the concrete without pozzolan materials. It was observed that blast furnace slag replacement ratio of 20% gives the best results with respect to chloride ion penetration and corrosion tests and observed that copper slag replacement ratio of 10% gives the seperior resistance compared to normal concrete.

Properties of Reformed Electric Arc Furnace Slag as Cement Admixtures (용융개질 전기로슬래그의 시멘트 혼화재로서 특성)

  • Kim, Kee-seok;Bae, In-kook;Seo, Joo-beom;Choi, Jae-Seok;Lee, Yoon-kyu;Kim, Hyung-seok
    • Resources Recycling
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    • v.24 no.6
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    • pp.31-37
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    • 2015
  • Ground granulated blast-furnace slag (GGBFS) which is by-product of steel industry has been recycled as a cement admixture though the other steel slags are used as aggregates. In this study, the electric arc furnace slag (EAFS) was used as a cement admixture after the reduction of iron oxide in the slag at the interface of molten slag and water quenching. Consequently, the reformed EAFS (REAFS) had higher grindability than that of granulated blast furnace slag. And in mortar tests, the strength properties of specimens using REAFS were 98% of plain specimens of GGBFS upto 20% replacement ratio of GGBFS with REAFS.

Generation of Hydration Heat of the Concrete Combined Coarse Particle Cement and Blast Furnace Slag (조분 시멘트와 고로슬래그를 조합 사용한 콘크리트의 수화발열 특성)

  • Noh, Sang-Kyun;Baek, Dae-Hyun;Jang, Duk-Bae;Kim, Young-Pil;Cha, Wan-Ho;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.05a
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    • pp.61-65
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    • 2008
  • This study, having combined and displaced blast furnace slag("BS" hereinafter) known as admixture material that delays hydration reaction with coarse particle cement("CC" hereinafter) collected in particle classification method during ordinary portland cement("OPC" hereinafter), reviewed the hydration heat characteristics affecting the concrete. To reduce hydration heat, the study plain-mixed which used 100% OPC for W/B 50% level 1, displaced CC at level 3 of 25%, 50% and 75% for OPC, and by displacing BS with admixture material at level 5 of 0%, 20%, 40%, 60% and 80% for cement(OPC+CC), experimented totally 16 batches. As a result of experiment, in the case of flow, the more CC displacement rate increased, the more it tended to decrease, and the more BS displacement rate increased, the more it decreased. Also, as for simple adiabatic temperature rise by the CC and BS displacement rates, it decreased as displacement rate increased, and particularly in the case of displaced BS of 80%, It showed temperature reduction effect of about 63% companing with plain. Compressive strength decreased in proportion to displacement rate, however strength reduction increment was shown to decrease with age progress.

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The Study on Foam Formation in Waterslag-Bentonite System (수광재와 백토조합물에서의 기포형성에 관한 연구)

  • 김종희;송한식
    • Journal of the Korean Ceramic Society
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    • v.14 no.4
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    • pp.248-255
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    • 1977
  • The effect of firing temperature, soaking time and batch composition upon the glass phase and pore formation as well as their distribution in slag foamed glass was investigated. Sulfur dioxide gas produced by the oxidation and reduction of metal sulfide in waterslag was attributed to foam forming agent. Slag foamed glass matrix was mainly composed of 35~60% glas phase and melilite crystalline phase. The increment of bentonite addition in batch lowered the foam forming temperature in studied system. The result showed also that the foam size distribution was broadened as th firing temperature wa inbereased.

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A Study on the Resistance of Chemical Attack for Cement Mortar (시멘트 모르터의 내약품성에 대한 고찰)

  • 문한영;김성수;유정훈;윤희경
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.183-188
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    • 1996
  • The durability of concrete structures decrease due to deterioration of concrete when they are constructed in marine or pollutional environments. In this study, the mortar specimens made from the five different types of cement were immersed in artificial seawater and four kinds chemical solution, and were measured the change of compressive strength and weight. The results show that the longer the immersed days are, the more the compressive strength reduction is. It has been remarked that the resistance of slag cement and ground granulated blast-furnace slag is excellent in chemical attack.

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Effect of Soil Amendments on Arsenic Reduction of Brown Rice in Paddy Fields

  • Kang, Dae-Won;Kim, Da-Young;Yoo, Ji-Hyock;Park, Sang-Won;Oh, Kyeong-Seok;Kwon, Oh-Kyung;Baek, Seung-Hwa;Kim, Won-Il
    • Korean Journal of Soil Science and Fertilizer
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    • v.51 no.2
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    • pp.101-110
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    • 2018
  • There is an increasing concern over arsenic (As) contamination in rice since Codex Committee on Contaminants in Food (CCCF) discuss on maximum levels for As in rice in 2010. This study was conducted to reduce As concentration in rice by soil amendment treatments in paddy field soils contaminated by As. The selected four amendments were poultry manure, agri-lime, steel slag, and gypsum with the addition of 3% or 5% (w/w) on a dry basis. The As reduction effect could not be verified, as a result of the pot test by adding poultry manure to the paddy soil around the mine located in Yesan. Among the agri-lime treated rice cultivated pots, the As concentration increased up to 32.1%. On the other hand, the content of As in the sample pots treated with steel slag and gypsum decreased by 65.4% and 63.4%, respectively. On the basis of the results of these pot experiments, the field test was carried out in the As polluted rice field around the mine located in Yesan, and when the four amendments were treated, the As content in the brown rice reduced in all the amendment treatments compared with the control plot. The As reduction in brown rice of the amendment was confirmed to be higher efficiency by the order of gypsum > steel slag > poultry manure > agri-lime. As a result of pot experiments using paddy soil around the mine located in Seosan, As stabilization efficiency in rice and As reduction effect could not be determined by comparison to the control. From the rice cultivated from agri-lime treated pot, As concentration increased by 15.8% in rice. On the other hand, the As content of the pots treated with steel slag and gypsum decreased by 39.1% and 60.2%, respectively. In conclusion, distinguished As reducing effectiveness could be expected by soil amendment treatments for rice cultivation.

Effect of Blast Furnace Slag on Rheological Properties of Fresh Mortar (고로슬래그미분말의 치환율 변화에 따른 굳지않은 모르타르의 레올로지 특성 검토)

  • Lim, Ji-Hee;Lee, Gun-Cheol
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.4
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    • pp.285-291
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    • 2014
  • Partial replacement of cement with blast furnace slag has many advantages such as the reduction of construction fee, the decrease of hydration heat and the increase of long-term strength. Hence, slag is widely used in practice. This study investigates the effect of slag on the rheological properties of cement paste and mortar. Three different types of slag (BS1, BS2 and BS3) with five different contents (0, 20, 40, 60 and 80 wt.%) were used to replace the cement. Each type of slag has different fineness. Water to binder ratio was 0.5. Test results showed that the partial replacement of BS1 and BS2 decreased flow and increased O-lot flow time, whereas that of BS3 caused an opposite effect, i.e., increased flow and decreased O-lot flow time. It was found that there was a good corelation between the values of yield stress and flow.

Long-Term Leaching Characteristics of Arsenic Contaminated Soils Treated by the Stabilization Method (안정화 처리된 비소오염토양의 장기 용출특성)

  • Yu, Chan;Yun, Sung-Wook;Baek, Seung-Hwan;Park, Jin-Chul;Lee, Jung-Hoon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1463-1474
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    • 2008
  • In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

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