• Title/Summary/Keyword: alumina cement

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Characteristics of Soil Pavement by Red Mud Content and Binder Type (레드머드 대체율에 따른 결합재별 흙포장재의 특성)

  • Kang, Suk-Pyo;Kang, Hye-Ju;Kim, Jae-Hwan;Kim, Byeong-Ki
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.1
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    • pp.37-44
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    • 2017
  • Red mud is an inorganic by-product produced from the mineral processing of alumina from Bauxite ores. The development of alkali-activated slag-red mud cement can be a representative study aimed at recycling the strong alkali of the red mud as a construction material. This study is to investigate the optimum water content, compressive strength, water absorption and efflorescence of alkali-activated slag-red mud soil pavement according to binder type. The results showed that the optimum water content, moisture absorption coefficient and efflorescence area of alkali-activated slag-red mud soil pavement increased but the compressive strength of that decreased as the redmud content increased.

Effect of various surface treatment methods of highly translucent zirconia on the shear bond strength with resin cement (고투명도 지르코니아의 다양한 표면처리 방법이 레진시멘트와의 전단결합강도에 미치는 영향)

  • Yu-Seong Kim;Jin-Woo Choi;Hee-Kyung Kim
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.3
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    • pp.179-188
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    • 2023
  • Purpose. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength of two types of zirconia (3-TZP and 5Y-PSZ) with resin cement. Materials and methods. Two different types of zirconia specimens with a fully sintered size of 14.0×14.0×2.0 mm3 were prepared, polished with 400, 600, and 800 grit silicon carbide paper, and buried in epoxy resin. They were classified into four groups each control, sandblasting, primer, and sandblasting & primer. Cylindrical resin adhered to the surface-treated zirconia with resin cement. It was stored in distilled water (37℃) for 24 hours, and a shear bond strength test was performed. The normality of the experimental group was confirmed with the Kolmogorov-Smirnov & Shapiro-Wilk test. The interaction and statistical difference were analyzed using a two-way ANOVA. A post-hoc analysis was performed using Dunnett T3. Results. As a result of two-way ANOVA, there was no significant difference in shear bonding strength between zirconia types (P > .05), but there was a significant correlation in the sandblasting, primer, and alumina sandblasting & primer group (P < .05). Dunnett T3 post-test showed that, regardless of the type of zirconia, shear bonding strength was sandblasting & primer > Primer > sandblasting > control group (P < .05). Conclusion. There was no difference in shear bond strength between the types of zirconia. The highest shear bond strength was shown when the mechanical and chemical treatments of the zirconia surface was performed simultaneously.

An Effect of $Al_{2}O_{3}$ on the Reaction between Molten Converter Slag and CaO pellet (용융전로(熔融轉爐)슬래그와 CaO펠렛의 상호반응(相互反應)에 미치는 $Al_{2}O_{3}$의 영향(影響))

  • Kim, Young-Hwan;Ko, In-Yong
    • Resources Recycling
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    • v.15 no.2 s.70
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    • pp.3-9
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    • 2006
  • As a basic study on the conversion of molten converter slag to the ordinary portland cement, the effects of $Al_{2}O_{3}$ addition on the interface reaction between solid CaO and molten converter slag has been studied. Alumina added converter slag whose basicity was controlled to 1 and 2 was melted and hold for 30 minutes in MgO crucible at $1500^{\circ}C$. Then sintered CaO pellet heated at the same temperature was dipped into the molten slag and held for 30minutes. After the reaction, the crucible was cooled in air and the specimen was cut off to the horizontal direction of the crucible. The dissolution rate of CaO pellet with the addition of $Al_{2}O_{3}$ was measured by the change of the radius or sintered CaO pellet and the interface layer was observed by SEM/EDX. As a result. At the basicity 2 slag, thickness of created $C_{3}S$ layer increased 3.5 times and quantity of $C_{6}AF_{2}\;or\;C_{4}AF$ phase increase 2 times than baisicy 1 slag.

The Fundamental Study on Properties of Concrete Using the Garnet with Industrial Wastes (산업부산물인 가네트를 이용한 콘크리트의 성질개선에 관한 기초적 연구)

  • Lim, Byoung-Ho;Park, Jung-Min;Kim, Tae-Gon;Kim, Wha-Jung
    • Magazine of the Korea Concrete Institute
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    • v.11 no.1
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    • pp.183-190
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    • 1999
  • This paper investigated the possibility of appling to concrete through fundamental experiment for garnet, which was industrial wastes generated in kyung pook region, in aspects of development of new materials and recycling of industrial wastes due to shortage of natural resources. Consequently, garnet powder showed the possibility of admixture as showed in the chemical composition because the content of silica and alumina in relation to pozzolanic activity was about 50%. The time of setting was more or less diminished as the increasing of replacement ratio of garnet. In flow test, flow values tended to increase to some degree as the increasing of replacement ratio of garnet. Therefore, application of garnet was expected to improve the workability of concrete. The compressive strength of mortar replaced by garnet was respectively increased as compared with plain mortar and the maximum strength was showed in replaced by 10%, however a little different to the change of W/B ratio. Also, the possibility of admixture to reduce the amount of cement and to improve the property of concrete was showed as the strength of mortar replaced by garnet was comparable to that by existing admixture(silica fume, fly-ash).