• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.605-608
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• 1999

In this paper, the application of limestone grain, which produced by being gathered electrically in the process of manufacturing of cement, to high fluidity concrete are investigated. High fluidity mortar is used for this experiment. According to the experimental results, especially, high viscosity and the loss of air content are accomplished by applying limestone grain as the partial substitution of fine aggregates. In case of hardened mortar, high strength development at early age can be achieved by using limestone grain. But excessive dosage of limestone grain can cause high drying shrinkage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.107-108
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• 2021

In the global trend of countries around the world announcing the declaration of carbon neutrality, the development of low-carbon cement in the cement industry can be seen as a very important issue that can determine the future development of the cement industry in the future. Therefore, this study evaluated the strength characteristics of limestone cement paste with limestone powder of CaCO3 and refinery desulfurization waste catalyst of high Al₂O₃ content, and using a Minitab mixture design to optimize a limestone cement content. As a resuls it was confirmed that limestone cement paste with 5-10% of limestone powder and 1.25-2.5% of the waste catalyst exhibits similar compressive strength to that of OPC.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.258-263
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• 2018

This study attempted to utilize ultrafine precipitated calcium carbonate for fluoride removal from the wastewater of electronics industries. An average particle size of the calcium carbonate was $0.96{\mu}m$, and pH of the aqueous slurry was 10 with 70% in mass. The suspension solution showed approximately 2 mL/hr of the sedimentation rate. The present calcium carbonate solution could be comparable to the conventional aqueous calcium source, $Ca(OH)_2$, for the neutralization and removal of fluoride ions. Depending on the amount of an additional alkali source, less amounts of test Ca-source slurries were required to reach the solution pH of 7.0 than that of using the aqueous calcium hydroxide. It was also found from XRD analysis that more calcium fluoride precipitates were formed by the addition of calcium carbonate solution rather than that of calcium hydroxide. In addition, Minteq equilibrium modelling estimated various ion complexes of fluoride and calcium in this process.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.163-169
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• 2009

The research performed a test concerning the fluidity and strength of concrete manufactured by combining lime stone power, fly ash, and blast furnace slag into two and three component systems, aiming at evaluating rheological and dynamic properties of concrete by manufacturing High Flowing Self-Compacting according to the strength changes of three levels. As a result of the research, for High Flowing Self-Compacting of 30 MPa, the combination of lime stone power 20% and fly ash 30% for securing quality and strength and adjusting viscosity satisfied the required performance. For High Flowing Self-Compacting of 50 MPa, the combination of blast furnace slag 10% and fly ash 20% satisfied the fluidity and strength of the requirement performance. Also, for 70 MPa that has many power contents, the combination of blast furnace slag 20% and fly ash 10% for the increase of fluidity and the reduction of viscosity satisfied the required performance. It is judged that fly ash in all combinations can be used to secure viscosity and reduce concrete amount. In addition, it is judged that for High Flowing Self-Compacting according to the levels of compressive strength the combination of three component system including fly ash is more appropriate than the combination of two component system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.195-202
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• 2004

In this study, it was founded to make the optimal mixture for producing concrete which is self-compacting, yet, and generates low heat of hydration by using flyash, blast furnace slags and limestone powders as binders in addition to cement while using super-plasticizers and viscosity agents as admixture agents. The structural behaviors of the concrete produced with the selected mixture were compared with those of the concrete currently using for construction of nuclear power plants. The study shows that the blended high fluidity concrete including limestone is better in workability and durability than the concrete currently in use for nuclear power plants.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.80-87
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• 2011

Blast furnance slag cement is a cement manufactured with using industrial by-product and it can reduce $CO_2$ by replacing cement when same uit volume concrete is produced. But Blast furnance slag has a short point that early strength of concrete is not good in winter season and it can be used. So, in this study, as long as replacement ratio of Blast furnance slag to original portland cement is under 30%, developed cement, ecoment, improve early strength of concrete and it applied to constructoin site. As a result, it improves 37% in terms of 1-day strength, it reduces 6.7% in terms of $CO_2$ emission when $1m^3$ concrete was produced. The importance and applicability of study wll be expected to increase cosidering global effort and green growth-strategy in country for reducing greenhouse gases.

• Resources Recycling
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• v.27 no.3
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• pp.58-65
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• 2018

For the recycling of coal ash from the domestic circulating fluidized bed boilers, a lime-based sorbent with 0.2~0.4 mm size was prepared by using limestone powder and CFBC fly ash. Mixing a small amount of slaked lime in the lime-based absorbent lead the formation of calcium silicate on the surface of the particle and the strength of absorbent particle was improved. As a result of comparing the desulfurization characteristics, it was found that the conversion rate was about 10% higher than that of commercially available limestone desulfurization used in the furnace, which is confirmed that it can be used as a desulfurization absorbent.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.413-418
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• 2021

In this study, as a basic study to use recycled limestone powder as a secondary product mixture for concrete, it was found that the compressive and flexural strengths were equal to or slightly improved compared to Plain up to 10% and 20% of the RLP mixing ratio, but the strength was rather decreased at 30% mixing. As a result of the heat of hydration experiment, as the RLP mixing rate increased, the heat of hydration decreased, and the elapsed time of the maximum heat was also delayed. As a result of the drying shrinkage test, as the fine powder RLP filled the internal pores of the cement mortar, the drying shrinkage decreased as the mixing rate increased. The compressive strength, water absorption rate, and compressive strength after freezing and thawing of the concrete block mixed with RLP 20% all satisfied the group standard criteria of the Korea Concrete Industry Cooperative Federation, confirming the possibility of use as a mixed material.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.287-292
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• 2001

This paper investigates the properties of high fluidity concrete incorporating lime stone powder and fly ash. Lime stone powder(LSP) and fly ash(FA) contents are varied with. According to test results, as LSP and FA contents increase, fluidity, air content and placeability shows a declining tendency. For the temperature history, both LSP and FA have favorable effects on reducing hydration heat, moreover, LSP reduces hydration heat more than FA. LSP shows undesirable strength loss as its content increases. FA also decreases the strength at early age, but it enhances later age strength. Accordingly LSP is expected to improve the quality at fresh concrete and reduce hydration heat, while it causes strength loss.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.569-574
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• 2002

Generally, the limestone powder is known to have some advantages in rheology of fresh concrete, resistance of material separation, and enhancement of strength at early ages. Recently, great attention is being paid to limestone blended cements in the manufacture of concrete, especially in the countries of Europe. The purpose of the present study is to establish the mechanical and durable properties of concrete containing slag and limestone powder. In this paper, the chloride ion penetration test, rapid carbonation test and rapid freezing-thawing test is carried out to study durability of concrete with various content of limestone powder. Futhermore, the strength of concrete is evaluated with various ages.