• Title/Summary/Keyword: pessimum

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An Introduction of Pessimum Program for the Identification of Alkali-Aggregate Reaction (콘크리트용 골재의 알카리-실리카 반응의 함량 최악조건)

  • 이상완;김수만;이평석
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.363-368
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    • 2000
  • This paper is an introduction of pessimum program for the identification of alkali-silica reaction of alkali-aggregate reaction which is known as one of a major factor of concrete deterioration. A series of gel-pat testing program was undertaken to observe the reactivity of potentially alkali-silica reactive concrete aggregates which were found to be reactive by previous petrographic examination (ASTM C 295). And then a pessimum program was performed in accordance with mortar-bar test method (ASTM C 227) with different percentage of those reactive components included in the fine aggregate source to determine the pessimum quantity. Chert and quartzite were found to be major components of reactive mineral/rock, and the pessimum condition for chert was about 3%, even though the test was performed with up to 25% of the component. In the case of quartzite, however, the mortar-bar expansion appeared to be directly proportional to the amount of quartzite sample with increasing tested quantity up to 35%. Both of the expansion results were well 3 and 6 month specified maximum limitation of 0.05% and of 0.1% respectively.

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Alkali-Silica Reaction of Mortar Containing Waste Glass Aggregates (폐유리 골재를 혼입한 모르터의 알칼리 실리카 반응에 관한 연구)

  • 박승범;이봉춘;권혁준
    • Journal of the Korea Concrete Institute
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    • v.13 no.3
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    • pp.213-220
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    • 2001
  • Incorporation of wastes glass aggregate in mortar may cause crack and this may result in the strength reduction due to alkali-silica reaction(ASR) and expansion. The purposes of this study were to investigate the properties of alkali-silica expansion and strength loss through a series of experiments which had a main experimental variables such as waste glass aggregate contents, glass colors, fiber types, and fiber contents. The steel fibers and polypropylene fibers were used for constraining the ASR expansion and mortar cracking. From the result, green waste glass was more suitable than brown one because of low expansion. And in this accelerated ASTM C 1260 test of waste glass, pessimum content can not be found. Also, when used the fibers with waste glass, there is an effect on reduction of expansion and strength loss due to ASR between the alkali in the cement paste and the silica in the waste glass. Specially, adding 1.5 vol.% of steel fiber to 20% of waste glass, the expansion ratio was reduced by 40% and flexural strength was developed by up to 110% comparing with only waste glass(80$\^{C}$ H$_2$O curing).

Expansion Properties of Mortar Using Waste Glass and Industrial By-Products (폐유리와 산업부산물을 사용한 모르터의 팽창특성)

  • 박승범;이봉춘
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.440-448
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    • 2002
  • Waste glass has been increased with the development of industry. The utilization of waste glass for concrete can cause the concrete to be cracked and to be weakened due to an expansion by alkali-silica reaction(ASR). In this study, ASR expansion and properties of strength were analyzed in terms of waste glass color(amber, emerald-green), industrial by-products(ground granulated blast-furnace slag, fly ash), and the content of industrial by-products for reducing ASR expansion caused by the waste glass. The possibility of using glass ground as pozzolanic properties was also analyzed. From the result of this study, the pessimum size of waste glass was 2.5∼1.2 mm regardless of waste glass color. And the smaller than 2.5∼1.2 mm waste glass is, the more decreasing expansion of ASR is. Also, the combination of waste glass with industrial by-products have an effect on reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass, and the glass ground of less than 0.075 mm is applicable as a pozzolanic material.

An Experimental Study on Alkali-Silicate Reaction of Fiber Reinforced Concrete Containing Waste Glass (폐유리를 혼입한 섬유보강 콘크리트의 알카리-실리카 반응에 관한 실험적 연구)

  • Lee, Bong-Chun;Lee, Taek-Woo;Kwon, Hyuk-Joon;Lee, Jun;Park, Seung-Bum
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.49-54
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    • 2001
  • Using waste glass in concrete can cause crack and strength loss by the expansion of alkali-silica reaction(ASR). In this study, ASR expansion and properties of strength were analyzed in terms of brown waste glass content, and fibers(steel fiber, polypropylene fiber) and fiber content for reduction ASR expansion due to waste glass. In this accelerated ASTM C 1260 test of waste glass, pessimum content can not be found. Also, when used the fibers with waste g1ass, there is an effect on reduction of expansion and strength loss due to ASR between the alkali in the cement paste and the silica in the waste glass. Specially, adding 1.5 vol.% of steel fiber to 20% of waste glass the expansion ratio was reduced by 40% and flexural strength was developed by up to 110% comparing with only Waste glass ( $80^{\circ}C$ $H_{2}$ O curing).

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An Experimental Study on Alkali-Silica Reaction of Mortar Containing Waste Glass and By-products (폐유리 및 산업부산물을 혼입한 모르터의 ASR에 관한 실험적 연구)

  • Lee, Bong-Chun;Kwon, Hyuk-Joon;Kim, Jeong-Hwan;Lee, Jun;Park, Seung-Bum
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.93-98
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    • 2001
  • Using waste glass in concrete can cause crack and strength loss by the expansion of alkali-silica reaction(ASR). In this study, ASR expansion and properties of strength were analyzed in terms of clear waste glass grading, and by-products(fly ash, blast-furnace slag) and by-products content for reduction ASR expansion due to waste glass. In this accelerated ASTM C 1260 test of waste glass, pessimum grading can be found. Also, when the by-products are used with waste glass, there is an effect on reduction of expansion and strength loss due to ASR between the alkali in the cement paste and the silica in the waste glass.

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Expansion Properties of Mortar Using Waste Glass and Industrial By-Products

  • Park, Seung-Bum;Lee, Bong-Chun
    • International Journal of Concrete Structures and Materials
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    • v.18 no.2E
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    • pp.125-132
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    • 2006
  • Waste glass has been increasingly used in industrial applications. One shortcoming in the utilization of waste glass for concrete production is that it can cause the concrete to be weakened and cracked due to its expansion by alkali-silica reaction(ASR). This study analyzed the ASR expansion and strength properties of concrete in terms of waste glass color(amber and emerald-green), and industrial by-products(ground granulated blast-furnace slag, fly ash). Specifically, the role of industrial by-products content in reducing the ASR expansion caused by waste glass was analyzed in detail. In addition, the feasibility of using ground glass for its pozzolanic property was also analyzed. The research result revealed that the pessimum size for waste glass was $2.5{\sim}1.2mm$ regardless of the color of waste glass. Moreover, it was found that the smaller the waste glass is than the size of $2.5{\sim}1.2mm$, the less expansion of ASR was. Additionally, the use of waste glass in combination with industrial by-products had an effect of reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass. Finally, ground glass less than 0.075 mm was deemed to be applicable as a pozzolanic material.

A Few Remarks on the Alkali-aggregate Reaction of Recycled-glass Concrete

  • Inada, Yoshinori;Kinoshita, Naoki;Matsushita, Seigo
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.549-554
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    • 2001
  • The authors have proposed that waste glass, which is crushed to pieces, can be used as a concrete aggregate. At the present time, recycled-glass concrete is used for sidewalk concrete blocks and pavement as glass is ornamental. However, in cases where recycled-glass concrete is used for structural concrete, strength and durability are required as structural concrete is exposed to the weather. Glass that is used generally is a mixture of SiO$_2$, Na$_2$O and CaO. SiO$_2$is the most likely cause of alkali-aggregate reaction when waste glass was used for concrete aggregate. In this study, an alkali-aggregate reaction test that is one of the important tests related to durability of aggregate was carried out far discussion of utilization of waste glass for concrete aggregate. From the results of the tests, it is found that glass is a reactive aggregate. The pessimum proportion of glass is about 75%. Then the cases of using fly ash, blast furnace slag and artificial zeolite for admixture materials were also examined for the purpose of prevention of alkali-aggregate reaction. from the results of the test, it was found that using them is an effective way to prevent alkali-aggregate reaction. The compressive strength in the cases of using admixture materials is larger than that without admixture materials.

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