• Journal of the Korean GEO-environmental Society
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• v.13 no.6
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• pp.33-39
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• 2012

With the increase of steel production research interest on the recycling of slag as a by-product also increases steadily. Currently in Korea a lot of researches on blast-furnace slag have been made. However, the researches on the steel slag have been rarely made. Also, a research of steel slag, especially the use of oxidation furnace slag as aggregates for concrete progress, is performing actively, but the research results on the furnace slag are almost nothing. Recently, the research about the furnace slag as backfill material and embankment material confirmed the possibility of the clay soil amendment. Therefore, the object of this study is to review the possibility as civil engineering materials for soil improvement and to find the optimum mixture ratio of furnace slag. This research analyzed the ingredient component of the reduced slag by SEM, XRF, XRD tests and examined the strength increase using unconfined compression tests when the clay and reduced slag are mixed each other. Through this test, the definite strength increase is confirmed according to the mixture of the reduced slag and the possibility of soil improvement is also confirmed based on this result. The object of the study is both utilizing the by-product for civil engineering purpose and effective recycling by the application of the furnace slag for soil improvement.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.111-121
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• 2022

It has been reported that current amount of coal ash remains almost 100 million tons and 5.85 million tons of blast furnace slag are generated annually in Vietnam. Vietnam government has encouraged the industries to increase the use of coal ash and blast furnace slag as construction materials as well as in cement production institutionally. However, limited can be applied in the construction field yet. Therefore, in this study, basic performance analysis on five different kinds of fly ash from Vietnam was conducted. In addition, the performances of blast furnace slags generated in Vietnam and Korea were compared and evaluated. Soil stabilizer compressive strength test and solidified soil unconfined compressive strength test were conducted as the basic data for the development of soil stabilizer applied to the soil mixing method using fly ash and blast furnace slag generated in Vietnam. The results showed that the Vietnamese fly ash and blast furnace slag can be used as the raw materials for soil stabilization and improvement.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.478-489
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• 2012

Each year, about four million tons of steel slag, a by-product produced during the manufacture of steel by refining pig iron in the converter furnace, is generated. It is difficult to recycle this steel slag as aggregate for concrete because the reaction with water and free-CaO in steel slag results in a volume expansion that leads to cracking. However, the steel slag used in this study is atomized using an air-jet method, which rapidly changes the melting substance at high temperature into a solid at a room temperature and prevents free-CaO from being generated in steel slag. This rapidly-cooled steel slag has a spherical shape and is even heavier than natural aggregate, making it suitable for the aggregate of radiation shielding concrete. This study deals with the radiation shielding property of concrete that uses the rapidly-cooled steel slag from the oxidizing process in the converter furnace as fine aggregate. It was shown that the radiation shielding performance of concrete mixed with rapidly-cooled steel slag is even more superior than that of ordinary concrete.

• Journal of the Korea Institute of Building Construction
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• v.2 no.2
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• pp.145-150
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• 2002

The hydration of cement paste occurs when the cement is miked with water. During the hydration, hydration heat causes the thermal stress depending on the site of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study conduction calorimeter and concrete insulation hydration heat meter were used to investigation the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment. As a result of this study, it was found that hydration heat of high-strength concrete was reduced by replacement of fly-ash and blast-furnace slag powder. In case of high-strength concrete using blast-furnace slag powder, the max-heat arrival time was delayed but an effect of heat reduction was lower than a case of high-strength concrete using fly-ash, because it was considered that the heat-dependence property of blast-furnace slag powder was higher than that of fly-ash.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.605-608
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• 2008

We have studied statistically about quality difference of Blast furnace slag Type Ⅲ that affects carbonation of concrete. According to KS F 2563 blast furnace slag was classified 3 types. Type Ⅲ blast furnace slag(specific surface area is $4000cm^2/g$) from different providers with Type A, the B and the C. The statistical technique was applied to exclude error of engineering judgement. T test and F test were used among 3 groups to investigate statistical meaning. The effect which on the quality of blast furnace slag type Ⅲ that affects carbonation of concrete is significant.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.453-456
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• 2006

In this study, the experiment was carried out to investigate and analyze the influence of fineness of blast furnace slag powder on the properties of high strength concrete. The main experimental variables were water/binder ratio 27.5, 31.5, 35.5(%) water content $165kg/m^3$ and mineral admixtures such as blast furnace slag powder. Even in a case where the ratio of blast furnace slag powder is 70%, using a fineness of 8000 grade afforded a higher strength development than using a plain concrete, which indicates the potential of high utilization in the future. Although it has been pointed out that the concrete using blast furnace slag powder has a problem of yielding relatively low rate of strength development in the early age, it is demonstrated that this can be resolved by using a powder with fineness greater than 6000 grade. It is considered necessary that powder fineness should be upgraded for the applications such as high performance concrete to be used in high strength required areas by considering hydration heat control and early strength requirements in the future.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.347-355
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• 2007

In this paper, estimation of the compressive strength of the concrete incorporating blast furnace slag subjected to high temperature was discussed. Ordinary Portland cement and blast furnace slag cement (BSC;30% of blast furnace slag) were used, respectively. Water to binder ratio ranging from 30% to 60% and curing temperature ranging from $20^{\circ}C{\sim}65^{\circ}C$ were also chosen for the experimental parameters, respectively. At the high temperature, BSC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated latent hydration reaction subjected to high temperature. For the strength estimation, the Logistic model based on maturity equation and the Carino model based on equivalent age were applied to verify the availability of estimation model. It was found that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.313-314
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• 2013

The study carried out the experiment with presenting as the fundamental data for developing non-cement by using red mud generated in blast furnace slag and bauxite generated in the process of manufacturing the pig iron process of manufacturing Al(OH)₃/Al₂O from as the binding material using the accelerator of NaOH. After fixing the thing and the NaOH adding the blast furnace slag and NaOH 10, 20, 30 (%) with 10, 20, 30 (%) substituted the red mud in the blast furnace slag and the experimental method carried out the experiment. And it measured the flexural strength and compressive strength and took a photograph EDS analysis and SEM. Consequently, the compressive strength was improved as the addition rate of the NaOH was high and the compressive strength according to the replacement ratio of the red mud was degraded. This is determined that film of the blast furnace slag is destroyed and it makes the hydration reaction condition and the intensity is revealed.

• KIEAE Journal
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• v.12 no.3
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• pp.115-122
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• 2012

Based on previous research and existing literature, this study examines the development of admixture, which increases the early concrete strength (1 and 3 day) by mixing blast furnace slag cement and concrete stimulant. The research on early strength development of concrete is necessary in dealing with the drawbacks of slow early strength concrete on site and to shorten the construction time. The study confirmed that when a high alkaline mortar mixture is mixed with blast furnace slag, the early strength of admixture exceeds that of ordinary portland cement (OPC). The use of calcium chloride ($CaCl_2$) promotes hydration of cement at low temperature and show similar strength as the blast furnace slag admixture. Although calcium chloride seems economically advantageous, it causes steel corrosion and its use in concrete should be further studied in-depth.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.69-78
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• 2013

PURPOSES : In this study blast furnace slag, an industrial byproduct, was used with an activating chemicals, $Ca(OH)_2$ and $Na_2SiO_3$ for carbon capture and sequestration as well as strength development. METHODS : This paper presents the optimized mixing design of Carbon-Capturing and Sequestering Activated Blast-Furnace Slag Mortar. Design of experiments in order to the optimized mixing design was applied and commercial program (MINITAB) was used. Statistical analysis was used to Box-Behnken (B-B) method in response surface analysis. RESULTS : The influencing factors of experimental are water ratio, Chemical admixture ratio and Curing temperature. In the results of response surface analysis, to obtain goal performance, the optimized mixing design for Carbon-Capturing and Sequestering Activated Blast-Furnace Slag Mortar were water ratio 40%, Chemical admixture ratio 58.78% and Curing temperature of $60^{\circ}C$. CONCLUSIONS : Compared with previous studies of this experiment is to some extent the optimal combination is expected to be reliable.