• Title/Summary/Keyword: 광물질혼화재

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Performance of cement concrete pavement incorporating mineral admixtures (광물질혼화재를 적용한 시멘트콘크리트 포장의 성능 평가)

  • Lee, Seung-Tae;Lee, Da-Hyun;Lee, Jae-Jun
    • International Journal of Highway Engineering
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    • v.12 no.3
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    • pp.113-119
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    • 2010
  • This study presents experimental findings on the performance of cement concrete pavement incorporating mineral admixtures such as ground granulated blastfurnace slag and silica fume. Flexural strength, compressive strength, charge passed, diffusion coefficient of chloride ions and initial surface absorption of cement concrete pavement incorporating mineral admixtures were periodically measured and the corresponding results were compared to those of plain concrete pavement. As a result, strength behaviors of concrete pavement were dependent on the types of mineral admixtures. However, it was true that incorporation of silica fume had a beneficial effect on compressive strength development. Furthermore, the application of mineral admixtures led to a lower diffusion coefficient of chloride ions compared to plain concrete pavement. Based on the experimental results, the present study would be helpful to design high-performance cement concrete pavement.

Resistance of Chloride Penetration into High Strength Concrete Containing Mineral Admixtures according to Curing Conditions (광물질혼화재 혼합 고강도콘크리트의 양생조건에 따른 염화물이온 침투저항성)

  • Moon, Han-Young;Kim, Byoung-Kwon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.2
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    • pp.185-194
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    • 2004
  • In recent years, construction company makes inroads into the world construction market, and receives the order of extra-large concrete structure under marine environment in south-east asia specially. At this point of time, to enhance the quality of concrete, we research the High Strength Concrete (HSC) containing mineral admixtures. In this study, therefore, HSC with various combination of ordinary portland cement(OPC), blast-furnace slag(SG), silica fume(SF), and expansion admixture(SS) are cured 23 and $35^{\circ}C$ considering the site weather, and are cured in water for 3, 7 or 56 days respectively. Test results show that the HSC cured at $35^{\circ}C$ gains higher early-age strength but eventually gains lower later-age strength compare with the HSC cured at $23^{\circ}C$. Especially, HSC with combination of OPC+SG+SF+SS or OPC+SG+SF show very excellent resistance of chloride penetration. The permeability of HSC was therefore enhanced as because of containing the proper content of SG, SF, and SS and making dense micro-structure of HSC.

Compressive Strength and Chloride Permeability of High Strength Concrete according to the Variety of Mineral Admixtures (광물질혼화재 종류별 고강도콘크리트의 압축강도 및 촉진 염소이온침투 특성)

  • Moon Han-Young;Kim Byoung-Kwon
    • Journal of the Korea Concrete Institute
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    • v.16 no.3 s.81
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    • pp.407-414
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    • 2004
  • The purpose of this study is to evaluate the ability to resist chloride ions penetration of the concrete structure under marine environment in south-east asia especially. In this study, high strength concrete(HSC) with various combination of ordinary portland cement(OPC), blast-furnace slag(SG) and silica fume(SF) are cured 23 and $35^{\circ}C$ considering the site weather, and are cured in water for 3, 7 or 56 days respectively. And to investigate the fundamental properties and the resistance of chloride penetration of various HSC, setting time, slump flow, compressive strength, void and ASTM C 1202 test were conducted. Test results show that the compressive strength of HSC is similar regardless of SG replacement ratio and total charge passed of chloride is the smallest at 40% replacement of SG. The compressive strength of G4FS HSC is, besides, outstandingly high at early age compare with other HSC, but the compressive strength of G4F HSC, which is vary according to curing temperature and condition, most high at the age after 7 days. Total passed charge of HSC get larger in the order G4FS

Freezing and Thawing Resistance and fundamental Properties of Antiwashout Underwater Concrete Containing Mineral Admixtures (광물질혼화재 혼합 수중불분리성 콘크리트의 물성 및 동결융해 저항성)

  • Moon HanYoung;Shin Kook-Jae;Song Yong-Kyu
    • Journal of the Korea Concrete Institute
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    • v.17 no.3 s.87
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    • pp.455-464
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    • 2005
  • Today the application of antiwashout underwater concrete to the construction sites is increasing steadily, while its reliability is in issue. Particularly, antiwashout underwater concrete is known to have very weak durability on frost attack, and hence Japan society of civil engineers(JSCE) regulated that not to use of antiwashout underwater concrete where the freezing and thawing is suspected. This study aims the improvement of the freezing and thawing resistance for antiwashout underwater concrete. From the results of fundamental test, FA20 and SG50 showed good performance in fluidity and long term compressive strength than control concrete. Meanwhile, MK10 marked the highest compressive strength through the whole curing age but a defect on fluidity was discovered. The results from the repeated freezing and thawing test show that the large volumes of air entrapped by cellulose based antiwashout underwater admixture gave bad effects to frost durability and hence not much benefits were confirmed from the use of mineral admixtures. However there were some increasing effects on frost durability of MK10 and SG50 by securing $6{\pm}0.5\%$ of entraining air. In the meantime, there was a increasing tendency of frost durability by increasing blame's fineness of ground granulated blast furnace slag.

Rheology properties of mortar using mineral admixture (광물질 혼화재를 혼합한 모르타르의 유변학적 특성)

  • Kim, Yong-Jic;Kim, Young-Jin;Choi, Yun-Wang
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.341-342
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    • 2010
  • This paper presents rheology of mortar using mineral admixture(Ground granulated blast furnace slag and Fly ash). The measurement of the rheology of mortar, including viscosity and yield stress, as well as its compressive strength were also carried our.

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Seawater Attack Resistance of Mortars Containing Mineral Admixtures (광물질혼화재 혼합 모르타르의 해수침식 저항성)

  • 문한영;이승태;최강식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.527-530
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    • 2002
  • In the present study, immersion test using artificial seawater was performed to evaluate the resistance of mortar specimens with or without ground granulated blast-furnace slag (SG) and fly ash (FA). Another variable was the fineness levels of SG (4,450, 6,000 and 8,000 ㎠/g). From the results of the immersion test for 270 days of exposure, the excellent resistance to seawater attack for SG mortar mixtures, especially in a high fineness levels, was confirmed. However, the reductions in compressive strength of FA mortar specimens was similar to those of OPC mortar specimens irrespective of replacement of FA.. In order to understand the deterioration mechanism due to seawater attack, X-ray diffraction (XRD) analysis were also carried out. Some reactants such as ettringite, gypsum, brucite and Friedel's salt were possibly detected through XRD technique.

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Scaling Resistance of Cement Concrete Incorporating Mineral Admixtures (광물질혼화재를 적용한 콘크리트의 스케일링 저항성 평가)

  • Lee, Seung-Tae;Park, Se-Ho
    • International Journal of Highway Engineering
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    • v.17 no.2
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    • pp.47-53
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    • 2015
  • PURPOSES: The scaling of a concrete surface caused by the combined effects of frost and de-icing salts is one of the main reasons for the need to repair transportation infrastructures in cold-climate regions. This study describes the results of attempts to determine the scaling resistance of concrete incorporating mineral admixtures such as fly ash, GGBFS, and silica fume, and subjected to the actions of frost and salt. METHODS : Conventionally, to evaluate the fundamental properties of concrete, flexural and compressive strength measurements are regularly performed. Based on the ASTM C 672 standard, concrete is subjected to 2%, 4%, and 8% $CaCl_2$ salt solutions along with repeated sets of 50 freeze/thaw cycles, and the scaling resistance was evaluated based on the mass of the scale and a visual examination. RESULTS : It was observed that silica fume is very effective in enhancing the scaling resistance of concrete. Meanwhile, concrete incorporating GGBFS exhibited poor resistance to scaling, especially in the first ten freeze/thaw cycles. However, fly ash concrete generally exhibited the maximum amount of damage as a result of the frost-salt attack, regardless of the concentrations of the solutions. CONCLUSIONS: It can be concluded that the scaling resistance of concrete is highly dependent on the type of the mineral admixture used in the concrete. Therefore, to provide a durable concrete pavement for use in cold-climate regions, the selection of a suitable binder is essential.

Setting Properties of Concrete with the Combination of Mineral and Chemical Admixture (광물질혼화재와 화학혼화제의 조합사용에 따른 콘크리트의 응결특성)

  • Kim Jong;Song Seung Heon;Jeon Chung Keun;Han Min Cheol;Oh Seon kyo;Han Cheon Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.505-508
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    • 2004
  • This paper investigated the setting and compressive strength of concrete with the combination of mineral and chemical admixture. According to test results, plain concrete with high early strength development type AE water reducing agent(HEAEWRA) and $10\%$ of CKD respectively had earlier setting time than concrete with AE water reducing agent by $0.5\~1.5$ hours. Setting time of concrete with retarding type AE water reducing agent(RAEWRA) and FA $30\%$, BS $60\%$ respectively retarded by as much as $4\~7.5$ hours compared with plain concrete. Plain concrete with HEA WRA, $10\%$ of CKD and RAEWRA had higher strength than that of AE water reducing agent by as much as 5MPa at 28days. From the result of the paper, it is found that the combination of mineral admixture and setting accelerating or retarding agent can reduce the hydration heat cracks by setting time difference and hydration heat reduction effects.

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Evaluation on the Sulfate Attack Resistance of Cement Mortars with Different Exposure Conditions (노출조건에 따른 시멘트 모르타르의 황산염침식 저항성 평가)

  • Lee, Seung Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6A
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    • pp.427-435
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    • 2012
  • In order to evaluate the effects of exposure conditions on the resistance to sulfate attack of normal and blended cement mortars, several mechanical characteristics of the mortars such as expansion, strength and bulk density were regularly monitored for 52 cycles under sodium sulfate attack. The mortar specimens were exposed to 3 different types of exposure conditions; 1) continuous full immersion(Exposure A), continuous half-immersion(Exposure B) and cyclic wetting-drying(Exposure C). Experimental results indicated that the maximum deterioration was noted in OPC mortar specimens subjected to Exposure B, showing the wide cracks in the portions where attacking solution is adjacent to air. Additionally, the beneficial effect of ground granulated blast-furnace slag and silica fume was clearly observed showing a superior resistance against sodium sulfate attack, because of its lower permeability and densified structure. Thus, it is suggested that when concrete made with normal cement is exposed to sulfate environment, proper considerations on the exposure conditions should be taken.

Fundamental Evaluation and Hydration Heat Analysis of Low Heat Concrete with Premixed Cement (저발열형 Premixed Cement를 사용한 콘크리트의 기초물성 평가 및 수화열 해석에 관한 연구)

  • Yoon, Ji-Hyun;Jeon, Joong-Kyu;Jeon, Chan-Ki;Kim, Ki-Hyung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.2 no.1
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    • pp.10-18
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    • 2014
  • This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.