• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 봄 학술발표회 논문집
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• pp.1-5
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• 1993

In the country, due to short comings of natural aggregates of good quality, it is common to use crushed stones. However, the investigation has not been done on the chemical reaction of crushed stones. This study tested and analyzed the aggregate chemical reaction by petrographic examination(ASTM C 295) for the test aggregates which had been tested by chemical method(ASTM C 289) in the first year. As a result, most of test aggregates didn't show any reaction but many have common deleterious mineral. Therefore, there exists the possibility of chemical reaction in petrogrphic point of view

• 한국광물학회지
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• 제14권2호
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• pp.85-98
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• 2001

콘크리트 구조물에 사용되는 골재의 화학적 안전성을 진단하는 방법 중의 하나인 암석기재학적 시험(ASTM C 295)에 관한 연구로서, 이 연구를 위하여 골재의 입도 분석, 피막 검사, 풍화 ·오염상태, 암석학적 기재, 그리고 알칼리-골재 반응성 광물 및 암석의 정성·정량적 분석을 실시하였다. 경남 울진군 매화천 유역 A, B 지역의 하천 골재에 대하여 암석기재학적 방법으로 검사한 결과 풍화상태는 F(신선) 등급과 WS(약간 풍화) 등급이며 골재의 피막과 오염 상태는 우려할 정도는 아니다. 알칼리-골재 반응 광물이나 구조적으로 취약한 암석이 함유된 골재는 매화천 A 지역 골재 전체의 26 wt.%, B 지역은 19 wt.%로 집계되는데 이는 양호한 골재로 볼 수 없기 때문에 화학적 방법과 몰탈바 방법으로 더욱 정밀한 시험을 거쳐 안전성이 확인되어야 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1989년도 가을 학술발표회 논문집
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• pp.1-4
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• 1989

Recently, as the natural aggregates are exhausted, using the crashed stones bring the possibility of the alkali-aggregate reactivity. In this study, the samples are collected from the stony moutains chosen by using a geoligical survey map and analyzed in terms of the amount and the shape of the reaction minerals by a polarization microscope and X-ray diffraction which beling to the petrographic examination of aggregates for concrete. From this study, most samples of the sedimentary rocks and the granitte of the ignious rocks show the possibility of the alkali-aggregate reactivity.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.97-102
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• 1993

In the country, due to short comings of natural aggregates of good quality, it is common to use crushed stones. However, the investigation has not been done on the chemical reaction of crushed stones. This study tested and analyzed the aggregate chemical reaction by Petrographic Examination(ASTM C 295),Chemical Metho(ASTM C 289) and Mortar-Bar Method (ASTM C 227). As a result, most of test aggregates didn't show any reaction but many have common deleterious mineral. Therefore, there exists the possibility of chemical reaction in petrographic point of view.

• 지질공학
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• 제17권4호
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• pp.589-599
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• 2007

본 연구는 한반도에너지개발기구(KEDO) 골재에 대하여 ASTM C 295를 적용, 암석기재학적 시험을 통하여 콘크리트를 위한 골재의 적합성을 타진하는데 목적이 있다. 시험에는 천연의 자갈골재와 모래골재를 재료로 하여 편광현미경, 실체현미경, XRD를 주로 사용하였다. KEDO의 천연골재 중 자갈골재의 23%, 모래골재의 5.1%가 화학적으로 불안정한 골재에 해당된다. 따라서 콘크리트용 KEDO 골재의 선정에 있어서 가능한 한 편마암과 같은 고변성 작용을 받은 변성암, 산성화산암, 엽리가 발달된 암석, 그리고 모르타르 봉 시험에서 불량한 골재로 확인된 암석은 피하여야 한다. 본 연구결과, 콘크리트용 KEDO 골재의 적합성 여부를 판단하기 위해서는 추가적인 화학적 시험과 모르타르 봉 시험을 거친 후 종합적으로 그 사용 여부를 결정함이 바람직하다.

• 지질공학
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• 제2권1호
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• pp.36-46
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• 1992

암석의 풍화 등급 정량화의 한 시도로써 각종 물리적 특성치의 변화 양상을 추적하고 이를 기존의 육안이나 현미경 관찰에 의한 풍화등급과 상호 비교 분석하였다. 이용된 물리적 특성치는 비중, 공극율, 초음파 종파속도 및 일축압축 강도였으며, 암석 관찰에 의한 풍화등급과의 상관은 공극율과 종파속도가 비중과 일축압축 강도에 비하여 상대적으로 좋은 상관도를 보여 심한 암상 차이만 조정된다면 공극율과 종파속도가 알려지고 있는 이상으로 효과적인 퐁화기준이 될 수 있을 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.13-18
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• 2003

The concrete structure can be easily damaged due to alkali-aggregate reaction. The alkali-aggregate reaction is a reaction between the alkalies(K or Na) in cement and an unstable mineral of the aggregates. There are several test methods to identify alkali reactivity of aggregates. In general, crushed stones are tested by petrographic examination, chemical method and 모르타르 바 method. This study tested alkali-aggregate reactivity of crushed stones that has different rock types such as granitic, volcanic, metamorphic and sedimentary rocks. Samples are collected from 12 local aggregate production companies. Alkali-reactivity of various rock types was evaluated by using ASTM C 227 and C 1260, and compared the test results of two test methods.

• 한국세라믹학회지
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• 제18권1호
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• pp.13-22
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• 1981

This study is to investigate the effective mineralizer in the manufacture of forsterite porcelain as a high frequency insulator. A mixture of $Mg(OH)_2$. and $SiO_2$.($\alpha$-Quartz) corresponding to the molar ratio of 2.0 MgO: 1.0 $SiO_2$ was prepared from the materials of high purity. It was heated to 140$0^{\circ}C$ at the rate of 20$0^{\circ}C$/hr, which was kept constantly for 1 hour, and one has made chamotte after cooling. Six kinds of glasses were prepared by an 0.1 atomic equivalent of K ions substitution-Ba, Bi, Zn, Cd, Zr-to the basic K-glass (0.333 $K_2O$.1.14 $SiO_2$) and were melted approximately at 150$0^{\circ}C$. The forsterite bodies were provided by adding each glass (10, 15, 20, 25, 30%) to the forsterite chamotte, which was fired at 1320, 1360, 1400, 144$0^{\circ}C$. (1 hr). One has examined the physical and dielectric properties for the specimens. The results of the experiments are as follows; 1. As for water absorption: Bodies were better vitrified with an addition and temperature change of Ba, Bi, Zn-glasses. The specimen containing Cd-glass showed deviation of slow decreasing, where as K-glass was completely not vitrified. 2. Bodies containing Ba, Zn, Bi-glasses appeared comparatively high Modulus of Rupture at 136$0^{\circ}C$, while containing Zr-glass had the highest Modulus of Rupture as the addition changes remarkably at 140$0^{\circ}C$. 3. It was estimated that 20-25% glass present in a forsterite bodies were in good conditions as for physical properties. 4. Specimens of Ba, Bi, Zr-glasses were superior as for dielectric properties, where among Ba-glass was most excellent. 5. Dielectric constant commonly increases in a slight gradient as firing temperature rises. 6. The petrographic examination showed that the bodies containing Ba, Bi-glasses had fine crystals, and were observed distinctly large mosaic crystals in the Zn-glass.