• Title, Summary, Keyword: Slag

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Properties of Blast Furnace Slag Cement Modified with Electric Arc Furnace Slag (전기로 슬래그를 치환한 고로 슬래그 시멘트의 특성)

  • Lee, Seung-Heun;Hwang, Hae-Jeong;Kwon, Sung-Ku
    • Journal of the Korean Ceramic Society
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    • v.43 no.7
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    • pp.408-414
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    • 2006
  • Properties of slag cement that contained 50 wt% of blast furnace slag were studied when replaced blast furnace slag powder with electric arc furnace slag powder. Electric arc furnace slag was aged for about 2 months in the air by being crushed to be 1-3 mm in size. As a result of the experiment, it was proven that the water content for obtaining the same consistency became decreased as slag is replaced with electric arc furnace slag instead of blast furnace slag. Also, the workability of mortar increased about 30% at the same ratio of water to binder when blast furnace slag was completely replaced with electric arc furnace slag. The compressive strength of mortar on the 28 days increased when a slag replacement rate became 10 wt%, however, it rather decreased when the slag replacement rate exceeded 10 wt%. The heat of hydration became higher for the first 14 h in case of the replacement of slag cement by electric arc furnace slag. Yet, it decreased when 14 h had passed. Therefore, when all blast furnace slag was replaced with electric arc furnace slag, about 15 cal/g heat of hydration decreased when it passed about 72 h.

Copper or ferrous slag as substitutes for fine aggregates in concrete

  • Thomas, Job;Thaickavil, Nassif N.;Abraham, Mathews P.
    • Advances in concrete construction
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    • v.6 no.5
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    • pp.545-560
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    • 2018
  • The ever-increasing cost of natural sand and the environmental impacts of extracting manufactured sand (quarry sand) calls for exploring the potential to use alternative materials as fine aggregates in concrete. Copper slag and ferrous slag are industrial by products obtained from the smelting process of copper and iron respectively. A large quantity of copper slag and ferrous slag end up being disposed as waste in landfills and this poses a serious threat to the environment. Copper slag and ferrous slag have similar physical and chemical properties as natural sand and also exhibit pozzolanic activity. This paper studies the technical feasibility of industrial by-products such as copper slag and ferrous slag to replace the fine aggregate in concrete by evaluating the workability, strength and durability characteristics of concrete. The test results indicate that the strength properties are not affected by 40% or 100% replacement of quarry sand with iron slag or copper slag. However, 40% replacement of quarry sand with iron slag or copper slag in concrete is recommended considering the durability aspects of concrete.

Carbonation Treatment of EAF Slag for Using Aggregate of Concrete (EAF-Slag의 콘크리트용(用) 골재(骨材)로의 활용(活用)을 위한 탄산화(炭酸化) 처리(處理) 연구(硏究))

  • Yoo, Kwang-Suk;Ahn, Ji-Whan;Lee, Kyung-Hoon
    • Resources Recycling
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    • v.18 no.3
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    • pp.36-41
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    • 2009
  • The objectives of this study are focusing on the issue with efficiently recycling for EAF slag as construction material such as an aggregate of concrete. This study can be classified mainly into two categories: the first section is the carbonation treatment of Electric Arc Furnace(EAF)-slag for obtaining soundness as using aggregate of concrete. And the second section is the application of carbonated EAF-slag on the mortar test to evaluate the stability and mechanical property, which is compressive strength, according to the replacement of EAF-slag on the mortar. It was known that pH of EAF-Slagle according to carbonation time decreases drastically to 7 within several sec of carbonation, and a calcite is formed on the surface of EAF slag. The formation of calcite during the carbonation process of EAF slag lead to fill at pore in the texture of EAF-Slag surface, and than the porosity of EAF-slag decreases with carbonation process. In the mortar test, compressive strength, according to the replacement of EAF-Slag to sand on the mortar, the compressive strength of mortar increased as the 50% replacement ratio of EAF slag for sand was above 10% higher than that of reference mortar according to 50% replacement of EAF slag.

The Development of Slag Based Materials for the Reformation of Soft Ground

  • Byeon, Tae-Bong;Kim, Hyung-Suek;Han, Ki-Hyun
    • Proceedings of the IEEK Conference
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    • pp.537-541
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    • 2001
  • For the development of reformation material of soft ground using the LD slag, the relation to the particle condition of LD slag and the pH behavior of slag dissolution water, extraction properties of slag, and origination of white water were investigated. When the LD slag is mixed with sea water, the pH of solution ranged between 9.47 and 10.0. On the other hand, when mixed with distilled water, the pH was about 10.4 to 12.1. For the as-received slag and the aged slag in sea water, a pH of 11.5 to 12.0 was observed when the particle size was less than 0.5mm. For the reoxidized slag in seawater, the pH of the solution was lower than 9.5 when the particle size was bigger than 0.075mm. For the aged slag and reoxidized slag, the pH of the solution remained constant when the addition ratio of sea water to the slag was higher than 500 times. The main elements dissolved from the slag were Ca and Mg ions. When the pH went over 9.0, the white water started to font which was caused by the CaCO$_3$and Mg(OH)$_2$.

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Corrosion Behavior of Dolomite Clinkers by Slag (Slag에 의한 돌로마이트 클링커의 침식거동)

  • 박재원;홍기곤
    • Journal of the Korean Ceramic Society
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    • v.36 no.1
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    • pp.30-35
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    • 1999
  • For dolomite clinkers used as stamp materials, the corrostion behavior of those by slag was inverstigated between 1550$^{\circ}C$ and 1650$^{\circ}C$. Fe2O3 among slag components was selectively penetrated into the grain boundaries of dolomite clinkers. In hot face, the magnesioferrite was preferentially formed by Fe2O3 component contained in dolomite clinker rather than Fe2O3 of slag. The corrosion steps of dolomite clinkers by slag were found as follows ; (1) The dicalciumferrite was formed by the reaction of the calcia within dolomite clinkers with Fe2O3 of slag. (2) The magnesia within dolomite clinkers reacted with the dicalciumferrite to from magnesioferrite and the residual calcia within dolomite clinkers reacted with the dicalciumferrite to form magnesioferrite and the residual calcia was dissolved into slag. (3) The magnesioferrite was corroded by CaO-SiO2 compounds of slag. With the temperature of slag increased, the magnesioferrite layer in hot face was decreased for dolomite clinker without Fe2O3 while the layer thickness and grain sizes of magnesioferrite was increased for dolomite clinker with Fe2O3.

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Prediction of compressive strength of slag concrete using a blended cement hydration model

  • Wang, Xiao-Yong;Lee, Han-Seung
    • Computers and Concrete
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    • v.14 no.3
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    • pp.247-262
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    • 2014
  • Partial replacement of Portland cement by slag can reduce the energy consumption and $CO_2$ emission therefore is beneficial to circular economy and sustainable development. Compressive strength is the most important engineering property of concrete. This paper presents a numerical procedure to predict the development of compressive strength of slag blended concrete. This numerical procedure starts with a kinetic hydration model for cement-slag blends by considering the production of calcium hydroxide in cement hydration and its consumption in slag reactions. Reaction degrees of cement slag are obtained as accompanied results from the hydration model. Gel-space ratio of hardening slag blended concrete is determined using reaction degrees of cement and slag, mixing proportions of concrete, and volume stoichiometries of cement hydration and slag reaction. Furthermore, the development of compressive strength is evaluated through Powers' gel-space ratio theory considering the contributions of cement hydration and slag reaction. The proposed model is verified through experimental data on concrete with different water-to-binder ratios and slag substitution ratios.

The Usage of Copper Slag as The Drainage Materials (동 수매 슬래그의 배수용 재료로써의 이용)

  • 민덕기;황광모;이경준;김현도
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.453-458
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    • 2001
  • Copper slag is produced about 700,000 tons annually though copper refining process in Korea. In the paper, a laboratory investigation was carried out to estimate the geotechnical properties of copper slag and examine the feasibility of using the copper slag as a substitute for conventional construction materials and the improvement of the soft clay deposit. The specific gravity of copper slag is 3.45, and pH is 7.83. And the size distribution of the copper slag is well graded, so usage of copper slag will be extended in Geotechnical engineering fields. Copper slag has the permeability of 3.502${\times}$10 ̄$^2$cm/sec, which is satisfied with the criterion of sand drainage materials.. At the same time, it is thought to be suitable material for sand mat since it meets JIS of grain size distribution. The content of CaO from steel slag is about 40 percent while that of CaO from copper slag is about 5 percent. Based on this fact, copper slag has less hardening property compared to steel slag. Therefore, copper slag can be used as vertical drains, filters, and sand mats for improving the soft deposit.

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Properties of reduced and quenched converter slag

  • Ko, In-Yong;Ionescu Denisa;T. R. Meadowcroft
    • Proceedings of the IEEK Conference
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    • pp.542-546
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    • 2001
  • Converter slag has some compositional similarities to portland cement. But it has no hydration properties due to it's quite high concentrations of FeO(20-35%), MnO(4-6.5%). So it is needed to reduce the concentrations of iron and manganese of converter slag to use as cement additives by enhancing it's hydration properties. In this study, converter slag was modified it's composition by mixing of silica, alumina and quenched BF slag and reduced in induction furnace and quenched in running water. The hydraulic properties and structures of modified and quenched converter slag are significantly changed depend on the amount and kinds of additives. The addition of alumina up to 10% and BFQ slag up to 20% by weight on converter slag was effective to enhance the hydraulic properties of modified and quenched slag. The addition of reduced and quenched converter slag up to 20% by weight in replacement of portland cement in mixing of concrete mortar were shown higher compressive strength than 100% cement concrete mortar.

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A Fundamental Study on the Converter Slag Coarse Aggregate Used in Concrete (전로슬래그 굵은골재를 콘크리트용으로 사용하기 위한 기초적 연구)

  • 문한영;유정훈;정호섭
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.233-236
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    • 1999
  • In this paper, we carried out fundamental experiments to use the steel manufacturing slag as a concrete aggregate. Generally there are two types of slag, the blast-furnace slag and the steel manufacturing slag. The latter is classified by the difference of manufacturing method of steel into the convertor slag and the electric-furnace slag. The steel manufacturing slag mainly contains SiO2 and CaO as the chmical composition. The reaction with water and a little of free CaO in the steel manufacturing slag makes the expansion of volume change. Therefore, we primarily investigated physical properties, expansion mechanism, pH value, aging effects and aging methods in the steel manufacturing slag. Then compressive strength of concrete with steel slag aggregate is measured.

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Fundamental Properties of Converter Slag Aggregate Treated with Accelerated Aging (촉진에이징처리한 전로슬래그 골재의 기초물성)

  • 문한영;유정훈;천승환
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.275-278
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    • 2000
  • In this paper, we carried out fundamental experiments to use steel manufacturing slag as a concrete aggregate. Generally, there are two types of slag, the blast-furnace slag and the steel manufacturing slag. The latter is classified by the difference of manufacturing method of steel into the convertor slag and the electric-furnace slag. The steel manufacturing slag mainly contains $SiO_2$ and CaO as the chemical composition. The reaction with water and a little of free CaO in the steel manufacturing slag made the expansion of volume change, Therefore, we primarily investigated physical properties, expansion mechanism, pH value, aging effect and aging methods in the steel manufacturing slag, Then compressive strength of concrete with steel slag aggregate is measured.

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