• Title/Summary/Keyword: low cement

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A Study on the Comparison of Physical Properties of OPC and Low-Heat Cement for the Evaluation of Concrete Properties of Low-Heat Cement Using Non-Carbonate Raw Materials (비탄산염 원료 활용 저열시멘트 콘크리트 물성 평가를 위한 OPC와 저열시멘트의 물성 비교에 관한 연구)

  • Kwon, Min Su;Heo, Jong-Wan
    • Cement Symposium
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    • s.49
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    • pp.31-32
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    • 2022
  • This study is to analyze the difference by comparing the physical properties of general Portland cement (OPC) and low-heat Portland cement (LHC) in the market to develop low-heat cement manufacturing technology that can minimize the amount of limestone by using non-carbonate circulating resources as raw materials. To this end, the mortar is being reviewed by evaluating the properties of the mortar, such as slump, strength, durability, and thermal insulation properties, with a difference in the mixing ratio.

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XRD and Image Analyis of Low Carbon Type Recycled Cement Using Waste Concrete Powder (폐콘크리트 미분말을 이용하여 제조한 저탄소형 클링커의 XRD 및 영상분석)

  • Shin, Hyeon-Uk;Song, Hun;Chu, Yong-Sik;Lee, Jong-Kyu;Park, Dong-Cheon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.252-253
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    • 2014
  • This study is to XRD and image analysis of low carbon type recycled cement from waste concrete powder and cement raw materials. Waste concrete powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste concrete powder is suitable for ordinary portland cement.

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Development of Low-activation Cement for Decreasing the Activated Waste in Nuclear Power Plant (원전 방사화 폐기물 저감을 위한 저방사화 시멘트의 개발)

  • Lee, Binna;Lee, Jong-Suk;Min, Jiyoung;Lee, Jang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.3
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    • pp.223-229
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    • 2017
  • When concrete is exposed to neutron rays for a long time, the concrete tends to become activated. If activated, it is classified as middle or low level radioactive waste. However, the great amount of the activated concrete is hard to dispose. In this study, low-activation cement was developed for decreasing the activated waste from shielding concrete around nuclear reactor. Furthermore, the manufactured low-activation was analyzed with activation nuclide Eu, Co. The low-activation cement showed great advantage for low-activation with detecting none of Eu and 3.75ppm of Co while ordinary portland cement showed 0.4~0.9ppm of Eu, 5.5~19.8ppm of Co content. As the results of physical properties of the low-activation cement, it is similar to type 1 ordinary portland cement and accords with type 4 low heat portland cement. Meanwhile, as for the chemical properties of the cement, it accords wite type 1 and 4 at the same time.

An Experimental Study on the Resistance of Low-Heat Cement Mortar in Chemical Attack (저발열시멘트 모르터의 호학저항성에 대한 실험적 연구)

  • 문한영;신화철;김성수;강석화
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.183-186
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    • 1998
  • This paper deals with 28, 56, 91 days age compressive strength and ratio of weight when OPC and Low-Heat cement mortar immersed in chemical solution. As a result of experiment, the resistance of Low-Heat Cement motar in chemical attack is more effective than that of OPC, because of lower $C_3$A content and Pozzolanic reactions. Especially in long term age compressive strength, Low-Heat cement mortar shows higher strength in all kind of chemical solution compared with compressive strength of OPC motar.

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Compressive Strength Properties of Steam-Cured Low Cement Mortar (증기양생한 저시멘트 모르타르의 압축강도 특성)

  • Yoon, Seong-Joe;Im, Geon-Woo;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.295-296
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    • 2023
  • This study evaluated the compressive strength after making mortar with low cement composition for carbon-neutral steam curing to respond to climate change. Blast furnace slag, fly ash, and ultra-high powder fly ash were used as substitutes for cement. The cement substitute was used at 40% of the mass of cement, and after steam curing, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age. As a result of the experiment, at the age of 1 day, the mixture using only cement showed the highest strength, but from the 3rd day, the specimen using ultra-high powder showed a high strength development rate, followed by blast furnace slag and fly ash.

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The Strength Characteristics of Solidified Sandy Soils with Mixing Conditions (배합조건에 따른 고결사질토의 강도특성)

  • Yu, Chan;Chang, Pyung-Wuck;Lee, Chang-No;Roh, Gwang-Ha
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.02a
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    • pp.84-95
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    • 1999
  • Laboratory experiments were performed to evaluate the strength characteristics of solidified sandy soils by portland cement with mixing conditions. Factors considered in the experiments were the fine content(<#200, %), cement content(%) and water-cement ratio and unconfined compressive strength tests were performed on samples at 7 and 28 cured day. Results of tests showed that for a low cement content(7%∼10%) the fine content was very important while for a high cement content the water-cement ratio was very important. For 7%∼10% cement content, the optimum fine content which gained maximum strength was about 30%. But for 13% cement content, low fine content and water-cement ratio were more useful than others. In the multi regression analysis, significant equation was gained.

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Effect of low-calcium fly ash on sulfate resistance of cement paste under different exposure conditions

  • Zhang, Wuman;Zhang, Yingchen;Gao, Longxin
    • Advances in concrete construction
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    • v.7 no.3
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    • pp.175-181
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    • 2019
  • Low-calcium fly ash (LCFA) were used to prepare cement/LCFA specimens in this study. The basic physical properties including water demand, fluidity, setting time, soundness and drying shrinkage of cement/LCFA paste were investigated. The effects of curing time, immersion time and wet-dry cycles in 3% $Na_2SO_4$ solution on the compressive strength and the microstructures of specimens were also discussed. The results show that LCFA increases the water demand, setting time, soundness of cement paste samples. 50% and 60% LCFA replacement ratio decrease the drying shrinkage of hardened cement paste. The compressive strength of plain cement specimens decreases at the later immersion stage in 3% $Na_2SO_4$ solution. The addition of LCFA can decrease this strength reduction of cement specimens. For all specimens with LCFA, the compressive strength increases with increasing immersion time. During the wet-dry cycles, the compressive strength of plain cement specimens decreases with increasing wet-dry cycles. However, the pores in the specimens with 30% and 40% LCFA at early ages could be large enough for the crystal of sodium sulfate, which leads to the compressive strength increase with the increase of wet-dry cycles in 3% $Na_2SO_4$ solution. The microstructures of cement/LCFA specimens are in good agreement with the compressive strength.

The Mechanical Properties of Concrete Using Blended Super Low Heat Cement (혼합형 초저발열 시멘트를 사용한 콘크리트의 물성-현수교 앵커리지 콘크리트 대상-)

  • 송용순;강석화;손명수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.341-344
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    • 1999
  • In the case of the offshore concrete structures like the anchorage block of a suspension bridge of Kwangan Grand Road, there is a need of the concrete which has low heat of hydration and good resistance for sea-water attack. In this study, the blended super low heat cement which satisfies that requirement was developed and several tests were carried out. The concrete using the blended super low heat cement showed lower adiabatic temperature rise than 3$0^{\circ}C$ and good early strength. Also, its passed charge(coulomb) to resist chloride ion penetration was very low.

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Effect of W/C and the Kinds of Cement on the Chloride Invasion Resistance of the Offshore Concrete (물-시멘트비 및 시멘트 종류가 해양콘크리트의 내염해성에 미치는 영향)

  • Shin Hong Chol;Yoo Jae Kang;Park Sang Joon;Kim Young Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.165-168
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    • 2005
  • This paper investigated the effect of W/C and the kinds of cement on the chloride invasion resistance of the offshore concrete. W/C set up 0.30, 0.35, 0.40 and The kinds of cement were used four(ordinary portland cement, ground granulated blast-furnace slag cement, belite cement, low heat portland cement). For the electrical migration test, NT BUILD 492's method was used to estimate the migration coefficient of chloride ion. As a result, the migration coefficients of chloride ion of concrete according to w/c were shown reducing with the w/c increasing, and according to kinds of cement were shown discrepancy in chloride invasion resistance. Especially blast-furnace slag cement was most low it. In the each cement, the compressive strength was shown related to the migration coefficient.

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