• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.153-160
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• 2010

This study aims to obtain technical data for improvement of utilization of Blast Furnace Slag(BFS), recycled aggregate in the future by complementing fundamental problems of BFS such as manifestation of initial strength and excessive alkali quantity as well as weakness of recycled fine aggregate through manufacturing of recycled fine aggregate mortar using BFS. The recycled aggregate includes the cement paste hardened as the surface and the type of the aggregate, which contains plenty of calcium hydroxide($Ca(OH)_2$) as well as the unhydrated cement. Accordingly, the objectives of this study are to inspect the manufacturing the recycled fine aggregate mortar used with blast furnace slag, to consider the effects of the recycled aggregate on the strength development of ground granulated blast furnace slag, and then to acquire the technical data to take into consideration the further usages of the recycled aggregate and blast furnace slag. In eluted ions from recycled aggregate, it showed that there were natrium($Na^+$) and kalium($K^+$), expected to be flown out of unhydrated cement, as well as calcium hydroxide($Ca(OH)_2$). Application of this water to mix cement mortar with ground granulated blast furnace slag was observed to expedite hydration as calcium hydroxide($Ca(OH)_2$) and unhydrated cement component were expressed to give stimuli effects on ground granulated blast furnace slag. The results of the experiment show that the recycled aggregate mixed with blast furnace slag has comparatively higher hydration activity in 7 day than the mortar not mixed with one in 3 day mortar does, causing the calcium hydroxide in the recycled fine aggregate to work on as a stimulus to the hydration of ground granulated blast furnace slag.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.93-104
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• 2007

This study evaluates the mechanical properties of steel fiber reinforced porous concrete for pavement according to content of slag aggregate and fly ash to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. As a result, void ratio and permeability coefficient of porous concrete for pavement increased a little as mixing rate of slag aggregates increased. Void ratio and permeability coefficient increased a lot as mixing rate of fly ash decreased. As fly ash was mixed, national regulation of permeable concrete for pavement(8% and 0.1 cm/sec) was met. Compressive strength and flexural strength decreased as mixing rate of slag aggregates increased, but they increased a lot as mixing rate of fly ash increased. Even when slag aggregates were mixed 50% with 5% fly ash mixed, national regulation of pavement concrete(18MPa and 4.5MPa) was met. In addition, compared to non-mixture, flexural strength increased about 22.8% when 0.75vol.% of steel fiber was added. Regarding sliding resistance, BPN increased as mixing rate of slag aggregates increased. But BPN decreased as fly ash was mixed. Compared to crushed stone aggregates, abrasion resistance and fleers-thaw resistance decreased as mixing rate of slag aggregates increased. When fly ash was mixed, abrasion resistance and freeze-thaw resistance improved remarkably. Compared to non-mixture, 10% mixture of fly ash improved abrasion resistance and freeze-thaw resistance about 5.6% and 14.3 respectively.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.367-375
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• 2009

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. However, it is inherent the problem which causes pop-out by free-CaO contained in slag In this study, we've got the plan to assure the chemical stability of EAF slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.112-118
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• 2012

Steel industry produces many by-products and wastes such as blast furnace slag, electric arc furnace slag, and converter slag. As in the case of rock, the main component of steel slag are CaO and $SiO_2$ ; further, steel slag is as alkaline as portland cement or concrete. Electric arc furnace oxidizing slag is possible to use as an aggregate for concrete ; however, it has been reclaimed because of it's expansibility caused by free CaO. Recently, a innovative rapid cooling method for melting steel slag has been developed in Korea, which reduces free lime content to minimum level and increases the stability of iron oxide. Therefore, this study describes the results of a series of research to utilize globular shape of electric arc furnace oxidizing slag fine aggregates made by rapidly cooled method for the construction industry by cooling rapidly melted slag from the steel industry. First of all, an experiment was carried out to investigate the quality characteristics of rapidly cooled electric arc furnace oxidizing slag fine aggregates in order to determine whether they can be applied to the construction industry. Then, by applying them to concrete of various particle sizes, we explored experimentally the desired condition to apply rapidly cooled electric arc furnace oxidizing slag fine aggregates to concrete.

• Clean Technology
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• v.12 no.4
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• pp.238-243
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• 2006

The aggregate properties of chilled converter slag reformed by atomizing liquid converter slag were investigated. The properties of mortars with various replacement of standard sand by chilled converter slag as recycled fine aggregates were investigated. The particle shape of chilled converter slag by atomizing was a sphere with an open cavity which is enclosed with two layers like a bored coconut. Specific gravity, unit weight and fineness modulus increased with increasing the replacement, and solid content had the maximum at the replacement of 75% and water absorption rate had the minimum at the replacement. The hardened mortars with higher replacements have the higher specific gravity and the denser texture.

• Resources Recycling
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• v.24 no.5
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• pp.63-71
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• 2015

The purpose of this study is to investigate the optimum replacement rate and material properties of eco-friendly recycled concrete using recycled coarse aggregates and rapid-chilled steel slag fine aggregates. The replacement rate of recycled coarse aggregates was increased from 30% to 50% of total volume of coarse aggregates and the rapid-chilled steel slag aggregates were substituted for 10% to 50% of total volume of fine aggregates. As a result, the increment of recycled coarse aggregates in concrete caused the reduction of the compressive strength. On the other hand, as increasing the replacement ratio of rapid chilled steel slag aggregates, the compressive strength was enhanced. Furthermore, the optimum use of rapid chilled steel slag aggregates was suggested up to 20~30% of fine aggregates and the use of it could be helpful to expand the replacement rate of recycled aggregates.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.145-151
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• 2014

This paper evaluated the quality properties of Finex Water Granulated Slag fine aggregate as part of a study to recycle the Finex Water Granulated Slag generated in korea, and examined the availability as fine aggregate for concrete by comparing properties (properties of fresh concrete, mechanical properties of hardened concrete) of concrete using Finex Water Granulated Slag fine aggregate with properties of concrete using river sand as fine aggregate. From the results of this study, it was found that quality properties of concrete using finex water granulated slag as fine aggregate and concrete using river sand as fine aggregate are equivalent level.

• Resources Recycling
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• v.25 no.2
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• pp.49-59
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• 2016

Steel slag is being recycled into industrial by-products for civil generated inevitably in the seasonal course, road and cement raw materials. However, the field of recycling most of the bottom portion is concentrated in the areas that are required to take advantage of the situation in various fields taking advantage of the steel slag. But various studies to take advantage of the steel slag as aggregate for concrete made for limiting slag was a situation that most of the studies are incomplete research on the suitability of as aggregate for concrete practical relates to an expandable suppressed. In this study, the separation of the slag aggregate according to the production methods to assess the feasibility aggregate for concrete aggregates, including through Steel making slag, a total of seven kinds of steel slag aggregate. Studies show that ordinary concrete, steel slag aggregate for aggregate and on the equally to take advantage of grading, chloride content standards such as to what is lacking, although appropriate aggregate of concrete include the deployment of only in special sectors through the combination was assessed to have a very high.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.345-352
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• 2017

Heavy weight concrete can be used in marine concrete structure to improve resistance against high wave energy. However, heavy weight aggregate, which is an indispensable material for heavy weight concrete, is difficult to be supplied in large quantities because its use is limited due to its high cost. In this work, the applicability of heavy weight by-products, copper and 3 month aged steelmaking slags, were evaluated as sources of heavy weight aggregate for marine concrete structures. Experimental results showed that copper slag was found to be a stable material for marine concrete structure. However, 3 month aged steelmaking slag showed significant expansion by $80^{\circ}$ water immersion test and ASTM C 1260 test. In addition, depth of chloride ion penetration in concrete was higher at which steelmaking slags were located. It was associated with porosity of steelmaking slag, and for this reason, steelmaking slag was not found to be suitable for marine concrete structure.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.361-368
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• 2003

As the supply of aggregate needed in the construction site becomes difficult due to preservation of environment and exhaust of aggregate resource, a research for replacement aggregate in shortage is being actively progressed and a copper slag is also a kind of replacing aggregate. To use copper slag as fine aggregate of concrete, many studies are already conducted in each of the advanced countries and in the state of applying these at the site. In the year of 2000 a Korea industrial standard of Copper slag aggregate for concrete was established in our country so that this can be applied in the construction site. This study is to find out whether copper slag is equipped with the physical and chemical requirements for the use in concrete aggregate, and to analyze the dynamic properties of copper slag concrete that replaces 25, 50, 75, 100% of fine aggregate. Copper slag study not only satisfies the using condition of fine aggregate, but also reveals high level of physical property compared to ordinary concrete up to 50% of sand replacement rate. In the future after confirming the durability of concrete using copper slag, it is judged to be advantageous for the preservation of environment to use this as a replacement material for natural aggregate.