• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.70-71
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• 2021

An increasing amount of red mud (RM) is being generated globally with the growth in alumi-num production. To avoid the RM becoming a pollutant, methods for effectively recycling RM at a low cost are being investigated. This study proposes a method for recycling RM as a construc-tion material. The cement paste with neutralized liquefied red mud had higher compressive strength than that of plain cement paste and cement paste with liquefied red mud without neutralization at 1 d of aging; this indicates that nitric acid neu-tralization increases the early-age strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.167-172
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• 1998

The purpose of this study is recycling of ready mixed concrete sludge as artificial aggregate by product technique of artificial aggregate in the normal temerature. For the qulity test of artificial aggregate using ready mixed concrete sludge, it is tested in the various aspect. Therefor, Quality of artificil aggregate is suitable as coarse aggregate except absoption, abrasion. For the application of aggregate in cement concrete, Coarse aggregate are replaced with artificial aggregate using ready mixed concrete sludge 100% of volume. The results of test shown that the artificial aggregate using ready mixed concrete sludge could be used replacement of coarse aggregate in cement concrete.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.119-123
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• 2005

• Resources Recycling
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• v.11 no.6
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• pp.24-30
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• 2002

Reduced and modified converter slag was ball milled and sieved to -200/+325 mesh. CaO,$SiO_2$, $Fe_2$$O_3$ was added to slag powder and mixed to make it similar to the composition of normal portlant cement. The pellet made of this powder was heated from $1250^{\circ}C$ to $1450^{\circ}C$ for 15 min～45 min. Most feasible condition for making slag cement clinker is the heating more than 20 min at $1450^{\circ}C$. The compressive strength of the mortar made of this slag cement clinker was better than that of normal port-lant cement in long time curing.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.465-474
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• 2022

Research on the recycling of waste concrete has been conducted mainly focusing on the production of high-quality recycled ag g reg ate, and as a result, standards and specifications for recycled ag g reg ate have been established. However, in the case of waste concrete powder, although a lot of research on its utilization has been conducted in Korea, an innovative technology leading to commercialization has not yet been announced. Recently, research on technology using waste concrete powder as a raw material for clinker or cement has been actively conducted in major overseas advanced countries. This study investigated the overseas cases with regard to high value-added recycling technology and commercialization trend of waste concrete powder for carbon neutrality in cement and concrete industries. A number of studies have reported that it is essential to completely separate the aggregate and hydrated cement paste fraction for recycling of waste concrete powder. Also in major foreig n countries such as EU and USA, commercialization and standardization of using waste concrete powder as a raw material for clinker or a additive for cement are now in progress beyond the R&D stage. Therefore, Research and standardization for recycling of waste concrete powder should be urgently carried out from the perspective of carbon neutrality in Korea.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.118-119
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• 2021

In this study, we confirmed the basic characteristics of paste and mortar 1:1, 1:2, 1:3 composition using concrete sludge solid content for the purpose of developing a resource-recycling cement secondary products. The 1:2 mortar formulation showed the best compressive strength. The steam curing strength is superior in the order of C20, BS40, BS20 and Control. it is judged that the FA combination is not suitable.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1757-1763
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• 2011

In recent years, accordance to industrial development project on railway investment, adverse environmental issues of the investment, such as disputed cases about recycling and usage of Ballast Cleaner excavated soil, have been continuously increasing. It will not only enhance the regulation of soil contamination but take considerable time and cost in future. In this study, we investigated soil contamination and burnability with soil of Chungang Line, Taebaek Line, Chungbuk Line, in order to seize a possibility of recycling Ballast Cleaner excavated soil for the natural materials and substantial heat sources, which are necessary resources for cement manufacturing process. As a result of this study, It is found that Ballast Cleaner excavated soil is satisfied with a standard. The excavated soil contains a lot of cement ingredients and fossil fuel dust incurred from freight transportation, so it is expected to use for ingredients of cement and replacement of heat sources.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.283-286
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• 2012

According to increase of the waste concrete occurrence, recycling has being important more and more. This study is to recycle the waste concrete powder, which is occurred in dry-process during recycling of construction waste. We have tried the waste concrete powder to apply as the replacement of the silica powder in cement extruding product. As a result, it is satisfied that the autoclave cured pannel of 50% replacement ratio of waste concrete powder staisty the level of the flexural strength of 14MPa stipulated by "KS F 4735 Extruding concrete panel" was the same thermal properties as base specimen.

• Resources Recycling
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• v.23 no.2
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• pp.71-80
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• 2014

In order to survey the numerical achievement of ELV recycling rate 95%, the definition of ELV recycling rate, material components of the automobile, improvement of ELV dismantling technology and status of ASR recycling were reviewed. On the other hand, field survey in details for dismantling works were conducted at Incheon Junkyard and H Junkyard. Although material recycling rate has been approaching 94% in dismantling step, status of ASR recycling is very unstable due to a ban of ASR recycling at cement kiln. It is clear that ASR recycling acts as a bottle neck in the ELV recycling. Therefore, it is important energy recycling of ASR should be enlarged to achieve ELV recycling rate 95%.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.539-546
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• 2013

Cement industry in 1997 began to use industrial waste in cement factory for purpose of resource recycling. However recently, environmental hazard of the cement in accordance with recycling of industrial waste have been raised a problem by contamination around the cement factory and heavy metal leaching in cement. In particular, the presence of $Cr^{6+}$ in cement has become a critical issue, the studies for minimizing of $Cr^{6+}$ in cement have been performed. But, in domestic, most of the research on heavy metal leaching was carried out from the perspective of the cement. Environmental safety assessment in terms of concrete is needed because cement is used to the concrete material. Therefore, this paper was evaluated heavy metals leaching of deteriorated concrete by severe conditions. test result showed that $Cr^{6+}$ were not detected from all the variables.