• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.179-180
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• 2018

Color concrete is produced by adding white portland cement and coloring agent. In Korea, colorant added to color concrete is expensive, durability evaluation in external environment is not verified and there is a tendency to avoid color concrete pouring. Red mud with a water content of 50% was prepared in liquid form using appropriate mixing water and additives for recycling as a coloring agent, the liquefied red mud manufactured was intended to show the possibility of using color concrete. In this paper, the application of red mud as an industrial by - product as a coloring agent for color concrete was investigated for the practical use of liquefied red mud by liquefying red mud and producing retaining wall block. As a result, it was found that all of the specifications stipulated in SPS-KCIC0001-0703 are satisfied.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.166-167
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• 2019

In this study, to test the performance of concrete used as a concrete admixture as a recycling method of CGS, gypsum was mixed and the chloride ion penetration resistance test of CGS and BFS substituted concrete was conducted. As a result, it was found that without gypsum type test specimen, the CGS sustituted test specimens had lower chloride ion penetration resistance than the BFS substituted specimens. When gypsum was added, it was confirmed that the chloride ion penetration resistance was poor regardless of the type of admixture. In addition, it was confirmed that both admixtures were less resistant to chloride ion penetration than OPC, regardless of the presence of gypsum. However, considering the uneven quality variation of coal, which greatly affects the quality of CGS, further research is needed.

• Journal of the Korea Concrete Institute
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• 제17권1호
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• pp.141-147
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• 2005

The development of automobile, vessel, rail road, and machine industry leads an increase of foundry production used as their components, which cause a by-product, waste foundry sand (WFS). The amount of the WFS produced in Korea is over 700,000 tons a year, but most WFS has been buried itself and only $5{\~}6\%$ WFS is recycled as construction materials. Therefore, it is necessary for most WFS to research other ways which can be used in a higher value added product. The study on recycling it as a fine aggregate for concrete or green sand has been in progress in America and Japan since 1970s and 1980s respaectively. In this study, two types of WFS were used as a fine aggregate for concrete. Nine types of concrete aimed at the specified strength of 30 MPa were mixed with washed seashore coarse sand in which salt was removed, and WFS and then appropriate mixture proportion of concrete was determined. Moreover, basic properties such as air contents, setting time, bleeding, workability and slump loss of the fresh concrete with WFS were tested and compared with those of the concrete mixed without WFS. In addition, both compressive strength of hardened concrete at each ages and tensile strength of it at the age of 28 days were measured and discussed.

• Journal of Environmental Science International
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• 제21권9호
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• pp.1059-1068
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• 2012

The purpose of this study was to develope the environmentally favorable method of roller compacted soil concrete pavement using industrial waste red mud. Red mud was the major solid waste produced in the process of alumina extraction from bauxite(Bayer process). For recycling purpose, red mud was treated and applied to use as concrete admixtures. To this end, laboratory test such as compressive strength of soil concrete, and field test such as construction characteristics of soil concrete pavement, had been conducted. From the study results, the compressive strength of soil concrete was strongly related to its matrix proportion and compaction energy. The optimum mix proportion was comprised of cement 300 $kg/m^3$, water 110 $kg/m^3$, fine aggregate 600 $kg/m^3$, course aggregate 1400 $kg/m^3$, red mud admixture 50 $kg/m^3$ and compaction energy above 2.86 $cm-kgf/m^3$. The $7^{th}$-day and $28^{th}$-day mean compressive strength of soil concrete were 43.8 MPa and 53.3 MPa each under the optimum condition. Pavement application of soil concrete using red mud admixture indicated that the proposed method was simple in case of construction and showed a good surface texture.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.171-174
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• 1999

The objective of this study is to investigate the properties of fine particles in the process of producing crushed fine aggregates under various fine particle contents. According to the test results, when fine particles are added as substitution of aggregates by about 10%, it shows that the qualities of interlocking block such as compressive strength, flexural strength and absorption ratio are improved. The application of fine particles provide various advantages in the sides of recycling of materials

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.275-280
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• 2001

Recycling of coal combustion by-product(Ash) are becoming more improtant in the utilization business as a result of the increased use of NOx reduction technologies at coal-fired power plants. current disposal methods of these by-products create not only a loss of profit for the power industry, but also environmental concerns that breed negative public opinion. Since inherent characteristics make these by-product suitable for building materials, several types of artificial aggregates and construction bricks are manufactured and tested to verify the engineering properties.

• Magazine of the Korea Concrete Institute
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• 제14권4호
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• pp.40-48
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• 2002

콘크리트는 시멘트의 수화반응으로 시간이 경과하면 굳어지게 되는 물질이다 따라서 레미콘 생산시 기기 및 장비 등에 고착된 콘크리트는 가수 혼합 등으로 분해가 불가능하므로 일단 콘크리트의 제조 및 운반작업이 종료된 후에는 즉시 세척하여야만 한다. 특히 레미콘 생산 현장에서와 같이 대량의 콘크리트를 제조할 경우에 있어, 일단의 콘크리트가 생산완료된 후 레미콘 트럭의 드럼내ㆍ외부 및 배치플랜트의 믹서ㆍ호퍼 등의 세척은 후속콘크리트 제조시 배합비의 정밀을 기하거나, 장비의 보존을 위하여 반드시 필요하게 되는데, 이때 발생하는 세척배수에서 골재를 제거한 것을 회수수라 한다.(중략)

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.669-674
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• 2001

Electric Arc Furnace Dust (EAF Dust) Is residual dust produced during the manufacturing of metal products from heavily heated electric arc furnace. Many researches have focused on recycling and reusing EAF Dust for industrial and construction purposes. However, most of these researches were aimed at obtaining useful heavy metal powders by treating toxic metallic materials in EAF Dust. Also, few researches dealt with using EAF Dust as admixture in concrete mixture (i.e., slag dust). In this study, EAF Dust is used as admixture in concrete mixture content considering economical feasibility and construction applicability. The concrete specimens mixed with EAF Dust is then tested in compression and tension to study its strength and ductility as well as its failure mechanism. The compression and tension (by split cylinder test) test results are compared to the results from the specimens without EAF Dust to understand the chemical stability and mechanical characteristic of concrete specimens with EAF Dust. For the experiment, 6 types of admixture added concrete were studied: ⑴Combination of EAF Dust and blast-furnace slag in 1 to 1 ratio, ⑵Combination of EAF Dust and blast-furnace slag in 1 to 2 ratio, ⑶EAF Dust only, ⑷blast-furnace slag only, ⑸fly ash only, and ⑹no admixture. The experimental results show that the strength of EAF Dust added specimen has lower early age strength but higher 28 day strength when compared to other specimens. Also, the Elastic Modulus of EAF Dust is higher(28 days) than other specimens. The study results prove that EAF Dust can be used as an effective admixture in concrete for specific usages.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.53-56
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• 2007

Recently, waste concrete emission has been increased by acceleration of urban development and the rapid growth of redevelopment projects, so recycling of waste concrete is actively progressed, But the usage is limited to a lower value added such as the roadbed material etc. To produce the high quality recycled aggregate, breaking and washing process is added to the existing process and inevitably increases the occurrence of particle, because old mortal is included in the recycled aggregate. Therefore, this study purpose is analysis the properties of lightweight foamed concrete made by waste concrete sludge which is the by-product from produce the recycled aggregate. In result, possibility of manufacture of lightweight foamed concrete which gives equal performance compared with ALC was detect(scope of density : $0.5{\sim}0.6$, scope of compressive strength : $3.5{\sim}4.0MPa$). And scope of porosity is as follow ; total porosity : $27{\sim}30%$, open porosity : $1{\sim}5%$

• Steel and Composite Structures
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• 제27권2호
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• pp.185-192
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• 2018

Fly ash can significantly improve concrete workability and performance, and recycling fly ash in concrete can contribute to a cleaner environment. Since fly ash influences pozzolanic reactions in concrete, mechanical behaviors of concrete containing fly ash differ from traditional concrete. Creep behaviors of fly ash concrete filled steel tube arch were experimentally investigated for 10% and 30% fly ash replacement. The axes of two arches are designed as circular arc with 2.1 m computed span, 0.24 m arch rise, and their cross-sections are all in circular section. Time dependent deflection and strain of loading and mid-span steel tube were measured, and long term deflection of the model arch with 10% fly ash replacement was significantly larger than with 30% replacement. Considering the steel tube strain, compressive zone height, cross section curvature, and internal force borne by the steel tube, the compressive zone height and structural internal forces increased gradually over time due to concrete creep. Increased fly ash content resulted in more significant neutral axis shift. Mechanisms for internal force effects on neutral axis height were analyzed and verified experimentally.