• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.407-415
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• 2008

Hydration reaction of Free-CaO is thought to be the main reason of expansion failure of slag. A lot of research institutions are conducting studies on solutions to this problem, and moreover it has been carried out how to make use of aggregates for concrete. While studies covering wide rage of blast furnace slag have been accomplished in the country, studies on steelmaking slag are insufficient. Therefore, this study aimed at analyzing basic physical properties of electric arc furnace oxidizing slag, which is the main material, and furthermore it focused on how to make use of aggregates for concrete examining chemical mechanism, which can be put to practical use. To address this issue, components of electric arc furnace oxidizing slag were analyzed with measurement of physical properties, followed by long-term strength and detailed durability analysis, which can evaluate the appropriateness of application of cement concrete. Besides the environmental conservation and recycling which can be obtained by application of industry byproducts, commercializing of electric arc furnace oxidizing slag as fine aggregates for cement concrete are expected.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.287-288
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• 2012

In this study, Analyzed the effect of the change in RFA and RCA substitution rate on the concrete containing BS bonding materials but no cement. The findings are as follows. First, the fresh concrete has less slump value and air contents as more RFA and RCA is used. In case of hardened concrete, as more RFA and RCA are used, the higher the compressive strength of concrete becomes. Especially, the compressive strength of concrete which used recycled aggregates only is found to be 2.2 times as high as that of concrete using natural fine and coarse aggregates only. But if the concrete is to be used as the structural concrete having the compressive strength of 13.8 MPa, the alkaline materials and some cement are required to be added.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.139-140
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• 2016

In this research, the possibility of wasted refractory aggregate pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory aggregate was replaced 2%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.206-207
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• 2014

Blast furnace slag is one kind of industrial by-product and was utilized with recycled fine aggregates for the manufacture of zero cement mortar. As the blast furnace slag was from different areas, the strength of the specimen using blast furnace slag showed different performances. In this study, blast furnace slag generated in different areas in Korea has been chosen, fundamental performances of the blast furnace slag blended mortar has been tested to evaluate the quality of the blast furnace slag. Results showed that difference for flowability is limited. As the alkali activation of the blast furnace slag, the compressive strength showed different results. The flexural strength showed little difference when the aggregates and types of blast furnace slag changed.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.293-297
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• 2016

This study was performed in order to obtain the effect of the compressive strength of the cured product with manufacturing conditions (amounts of fine aggregate and different types of alkali activator). Material which is the basis of the cured product was used for the blast furnace slag, which has a latent hydraulic activity. Consequently, when using sodium hydroxide as the alkali activator, it is possible to obtain a higher compressive strength than using the calcium hydroxide. And also, it can be added a 10% of fine aggregate with blast furnace slag to improve the compressive strength.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.97-104
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• 2023

In order to maximize the utilization of recycled fine aggregate, high strength mortar made of 100 % recycled fine aggregate was prepared, and its physical properties were evaluated to determine the possibility of using recycled fine aggregate as structural aggregate. The effect caused by the amount of nanosilica on the physical properties of w/b 0.2 recycled fine aggregate mortar consisting of cement, silica fume, and blast furnace slag. To improve the dispersion of nanosilica inside mortar, an aqueously dispersed nanosilica solution by ultrasonic tip sonication was prepared, and incorporated into the mortar to evaluate changes in mortar flow, porosity and compressive strength depending on nanosilica content. According to the experimental results, mortar flow decreased as the replacement ratio of nano-silica increased. As the replacement ratio of nanosilica increased up to 0.75 %, the porosity decreased and the compressive strength increased, but, at a replacement ratio of 1 %, the porosity increased and the compressive strength decreased. It was confirmed that the nano-silica replacement ratio of 0.75 % was optimum proportion to maximize the mechanical performance of high-strength recycled fine aggregate mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.56-57
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• 2016

Recently amongst Korea's construction companies there has been heightened interest in environment load reduction and resource recycling. As a result, the construction industry is examining recycled materials alternative to cement and blast-furnace slag (BS henceforth) cement, such as waste refractories and desulfurized plaster. This study analyzes the liquidity and intensity characteristics of mortar according to changes in replacement ratios of waste refractories and desulfurized plaster, used as industry by-products in mortar environments that use BS 3-type cements and circulated fine aggregate. As a result, the greater the increase in replacement ratios of desulfurized plaster, the greater the increase in liquidity and air quantity, as well as compression strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.61-62
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• 2011

This study reviewed the effect of W/B, WO and curing method on the quality properties of RA using the BS brick under the zero cement condition. compressive strength was found to show an increasing trend as W/B increased, but to show a improvement in case steam curing was conducted, showing a higher increase at 1 day age in comparison with 7 day age. In addition, the compressive strength on the mixing of WO didn't show any specific trend. The absorption tended to decrease as W/B increased and met the less than 10% regulation value at 30~35% W/B in case WO was used, there appeared a decrease attributable to capillary pore filling effect due to saponification. On the other hand, compressive strength increases, th absorption showed a gradually decreasing tendency.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.8
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• pp.3-11
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• 2018

In this study, total nine R/C beams, designed by the PVA Fiber with ground granulated blast furnace slag and recycled fine aggregate were constructed and tested under monotonic loading. In the material development, micromechanics was adopted to properly select the optimized range of the composite based on steady-state cracking theory and experimental studies on the matrix and interracial properties. Experimental programs were carried out to improve and evaluate the structural performance of the test specimens: the load-displacement, the failure mode, the maximum strength, and ductility capacity were assessed. Test results showed that test specimens (BSPR-20, 40) was increased the maximum load carrying capacity by 3~6% and the ductility capacity by 9~14% in comparison with the standard specimen (BSS). And the specimens (BSPR-60, 80, 100) was decreased the maximum load carrying capacity by 0~4% and the ductility capacity by 79% in comparison with the standard specimen (BSS) respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.38-39
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• 2016

In this research, the possibility of wasted refractory powder pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory powder was replaced 10 %.