• Title/Summary/Keyword: 치환율

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Strength Properties of SBR-Modified Concretes Using Ground Granulated Blast-Furnace Slag (고로슬래그 미분말을 이용한 SBR혼입 폴리머 시멘트 콘크리트의 강도특성)

  • ;;Yoshihiko Ohama
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.315-320
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    • 2002
  • The effects of slag content and polymer-binder ratio on the strength properties of the polymer-modified concretes using ground granulated blast-furnace slag and a styrene-butadiene rubber (SBR) latex are examined. As a result, the compressive, tensile and flexural strengths of the SBR-modified concretes using slag increase with increasing polymer-binder ratio and slag content, and maximized at a slag content of 40 %. In particular, the SBR-modified concretes with a slag content of 40 % provide approximately two times higher tensile and flexural strengths than unmodified concretes. Such high strength development is attributed to the high tensile strength of SBR polymer and the improved bond between cement hydrates and aggregates because of the addition of SBR latex.

A Study on Freezing and Trawing Resistance of Concrete with the Ratio of Ground Granulated Blast-Furnace Slag Replacement (고로슬로그 미분말의 치환율에 따른 콘크리트의 동결융해 저항성에 관한 연구)

  • 최세규;김생빈
    • Magazine of the Korea Concrete Institute
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    • v.9 no.5
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    • pp.149-155
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    • 1997
  • 고로슬래그 미분말을 사용한 콘크리트\ulcorner 수화속도가 느려 어린 재령시 동해의 영향을받기 쉽다. 본 연구에서는 고로슬래그 미분말을 사용한 콘크리트의 동결융해 저항성을 알아보기 위해 고로슬래그 미분말의 치환율과 물-결합재비를 변화시켜 제조한 콘크리트에 대해 동결융해시험을 실시하였다. 또한 동일한 치환율, 물-결합재비의 콘크리트에 AE제를 첨가시켜 동결융해 저항성의 개선효과를 알아보았다. 시험결과 고로슬래그 미분말의 치환율이 증가할수록 동결융해 저항성은 작게 나왔다. 또한 non-AE 콘크리트의 경우 물-결합재비가 51%, 45%일 때 내구성지수는 각각 2.4%, 40.0%이하로 매우 나쁘게 나타났으나, AE콘크리트의 경우 물 -결합재비가 45%와 51%인 콘크리트의 내구성지수는 각각 90.2% 80.9%이상으로 동결융해 저항성이 매우 우수하게 나타났다.

Evaulation of Adiabatic Temperature Rise for Concrete with Blast-Furnace Slag replacement (고로슬래그 미분말 치환율에 따른 콘크리트의 단열온도상승 평가)

  • Kim, Joo Hyung;Lee, Do Heun;Jung, Sang Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.1
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    • pp.18-24
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    • 2013
  • Recently, the interest is increasing about the eco-friendly concrete. Accordingly, the blast furnace slag(BFS), a by-product of industry is known for improving the durability through compaction in concrete and is expanding the use. The research about BFS in concrete be accomplished frequently. In this study, we should know the hydration characteristic of BFS concrete the through the adiabatic temperature rise test due to the replacement of a variety of BFS. In addition, we produced the regression analysis factors through the test result and analyzied the effect for the replacement of BFS. According to test results, the compressive strength showed a slight degradation or equal and the the adiabatic temperature rise figure and rising factors are went down for rising replacment of BFS. In the future, the study about the adiabatic temperature rise equation for the various replacement of BFS and binder is considered necessary.

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A Fundamental Properties of the Concrete Using Coarse Particle Cement and Mineral Admixture (굵은입자 시멘트와 광물질 혼화재를 조합 사용하는 콘크리트의 기초적 특성)

  • Han, Cheon-Goo;Jang, Duk-Bae
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.1
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    • pp.131-138
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    • 2010
  • This research intends to analyze the basic characteristics of cements(hereinafter "CC") with affordable price and particle distribution effective as hydration heat face which are discharged at the outlet of smashing process of ordinary portland cement(hereinafter "OPC") manufacturing process such as fluidity, rigidity, temporary insulation temperature increase amount etc to review the potential of developing "CC" to 3 ingredients low heat cement that substitutes fly ash and blast furnace slag(hereinafter "BS"). As a result of experiment, fluidity tended to decrease with increase in CC substitution rate, and increase with increase in FA+BS substitution rate. Air amount tended to slightly decrease with increase in CC substitution rate, and decrease with increase in FA+BS substitution rate. Condensation characteristics were such that condensation time was delayed with increase in CC and FA+BS substitution rate. As for the temperature rising amount by temporary insulation, peak temperature decreased with increase in CC substitution rate and increase in FA+BS substitution rate in general, and thereafter, temperature tended to decrease slowly. Compressive strength decreased with increase in CC and FA+BS substitution rate, and as aging goes on, long term strength was equivalent to plain or higher. By and large, when FA+BS was substituted to CC, fluidity and air amount tended to decrease, but hydration heat face showed good reduction effects, suggesting possibility of development to 3 ingredients low heat cement.

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The Effect of the Replacement of Grinded Fly Ash according to Curing Temperature on Repair Mortar Based on Polymer Admixture (폴리머수지 기반 보수모르타르에서 양생온도에 따른 미분쇄된 플라이애시 치환율의 영향)

  • Sim, Jae-Il;Mun, Ju-Hyun;Yun, In-Gu;Jeon, Young-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.116-124
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    • 2015
  • The objective of this study is to evaluate the effects of the replacement levels of grinded fly-ash on the repaired mortar based on a polymer. The main parameters are the curing temperature and replacement levels of grinded fly-ash. The curing temperature and the replacement levels of grinded fly-ash are varied at $40^{\circ}C$, $20^{\circ}C$ and $5^{\circ}C$, and between 0% and 35% of the total binder by weight, respectively. The flow in fresh mortar and compressive strengths according to ages, the relationship of stress-strain, elastic modulus and modulus rupture in hardened mortar, as well as scanning the electron microscopy and the X-ray diffraction of mortar, were measured, respectively. The test results showed that the flow, elastic modulus and modulus rupture are great in mortar specimens with 20~30% of the replacement levels of grinded fly-ash. In addition, compressive strengths according to ages were affected by the replacement levels of grinded fly-ash and the curing temperature indicated that the strength development ratio of mortar with 20% of the replacement levels of grinded fly-ash was greater than others. In the prediction of the compressive strength specified by the ACI 209 code, the strength development at an early and late age can be generalized by the functions of the replacement levels of grinded fly-ash and the curing temperature. In the analysis of scanning the electron microscopy and the X-ray diffraction, the number and intensity of peaks increased and the form of CSH gels on the surface of the particle of grinded fly-ash was observed.

An Experimental Study on the Influence of High Fineness Fly Ash and Water-Binder Ratio on Properties of Concrete (콘크리트 특성에 미치는 고분말도 플라이애쉬의 치환율 및 물-결합재비 영향에 관한 실험적 연구)

  • Lee, Sang-Soo;Song, Ha-Young;Lee, Seung-Min
    • Journal of the Korea Concrete Institute
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    • v.21 no.1
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    • pp.29-35
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    • 2009
  • Recently, the press and institute recognized fly ash as it had excellent performance. Its research and applications are on the rise largely as a substitute for cement. On the contrary, it is in a situation that the regulation of high fineness fly ash remains at a low level. As for the fly ash in $3,000{\sim}4,500\;cm^2/g$ class fineness regulated in KS L 5405, it is used by substituting it around the unit weight of cement 20%. Accordingly, the regulation in upper classification is in a situation of being insufficient. Therefore, this study aimed to establish 4000, 6000, and 8000 class of fineness of fly ash and three levels of substitute like 15%, 30%, and 45% in order to analyze the substitute and effect of water-binder ratio for fly ash that affected the properties of ternary system concrete. As a result of experiment by planning water-binder ratio for two levels like 40% and 50%, the more replacement ratio and fineness of fly ash increased in the performance not hardened, the more the fluidity increased. This study has found out that the air content decreased, and that there was setting acceleration and it decreased the heat of hydration. In addition, as for the strength properties in a state of performance hardened concrete, the more the replacement ratio and the ratio of water-binding materials increased, the more it had a tendency of being decreased.

Mechanical Properties of Recycled Aggregate Concrete Containing Fly Ash (순환골재를 이용한 플라이애시 콘크리트의 역학적 특성)

  • Yang, In-Hwan;Jeon, Byeong-Gwan
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.2
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    • pp.144-151
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    • 2017
  • The mechanical properties such as compressive strength and elastic modulus of recycled aggregate concrete containing fly ash are investigated in this study. The experimental parameters were replacement ratio of recycled coarse aggregate(RCA) and fly ash. Replacement ratio of RCA was 0, 30, 50, and 70% and replacement ratio of fly ash was 0, 15, 30%. The experimental results were extensively discussed about compressive strength and elastic modulus of concrete at ages of 7, 28 and 91 days. Compared with concrete not containing fly ash, the decrease of compressive strength and elastic modulus of concrete containing fly ash with the replacement ratio of 30% was significant. Therefore, the test results represented that the fly ash replacement ratio of less than 30% was favorable in terms of mechanical properties of recycled coarse aggregate concrete.

Strength and Durability of Polymer-Modified Mortars Using Ground Granulated Blast-Furnace Slag (고로슬래그 미분말을 혼입한 폴리머 시멘트 모르타르의 강도 및 내구성)

  • 주명기;김남길;연규석
    • Journal of the Korea Concrete Institute
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    • v.14 no.2
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    • pp.164-170
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    • 2002
  • Effect of the polymer-binder ratio and slag content on the properties of combined wet/dry-cured polymer-modified mortars using granulated blast-furnace slag are examined. Results shows that the flexural and compressive strengths of polymer-modified mortar using the slag tend to increase with increasing slag content, and reaches a maximum at a slag content of 40 %, and is inclined to increase with increasing polymer-binder ratio. Water absorption, carbonation depth and chloride ion penetration depth tend to decrease with increasing polymer-binder ratio and slag content. Accordingly, the incorporation of slag into polymer-modified mortars at a slag content of 40% is recommended for a combined wet/dry curing regardless of the types of polymer.

Effect of Superplasticizers and Admixtures on the Fluidity and Compressive Strength Development of Cementless Mortar Using Hwangtoh Binder (혼화제·재가 무시멘트 황토 모르타르의 유동성 및 압축강도 발현에 미치는 영향)

  • Yang, Keun-Hyeok;Hwang, Hey-Zoo;Kim, Sun-Young;Song, Jin-Gyu
    • Journal of the Korea Concrete Institute
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    • v.18 no.6 s.96
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    • pp.793-800
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    • 2006
  • This paper reports test results to assess the influence of superplasticizers and different admixture on the flow and compressive strength development of cementless mortar using developed hwangtoh binder. Test specimens were classified into four groups: series for I the mixing ratio of superplasticizers, series II for a kind and replacement level of admixtures according to the variation of water/hwangtoh binder ratio, series III for the specific surface area and replacement level of ground granulated blast-furnace slag and series IV for the replacement level of powered superplasticizer agent developed to improve slump loss of concrete. The proper replacement level of each admixture is proposed for enhancement the flow and compressive strength of the hwangtoh binder mortar.

Variation of Stress Concentration Ratio with Area Replacement Ratio for SCP-Reinforced Soils under Quay Wall (치환율에 따른 안벽구조물 하부 SCP 복합지반의 응력분담비)

  • 김윤태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.16 no.1
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    • pp.18-26
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    • 2004
  • In order to accelerate the rate of consolidation settlement, to reduce settlement, and to increase bearing capacity for soft ground under quay, sand compaction pile method (SCP) has usually been applied. SCP-reinforced ground is composite soil which consists of the sand pile and the surrounding soft soil. One of main important considerations in design and analysis for SCP-reinforced soils is stress concentration ratio according to area replacement ratio. In this paper, the numerical analysis was conducted to investigate characteristics of stress concentration ratio in composite ground. It was found that stress concentration ratio of composite ground is not constant as well as depends on several factors such as area replacement ratio, depth of soft soil, and consolidation process. The values of stress concentration ratio increase during loading stage due to stress transfer of composite soil, and reach up to 2.5∼12 according to area replacement ratio at the end of construction. After the end of consolidation, however, these values are converged to 2.5 to 6.0 irrespective of area replacement ratio due to increase in effective stress of soft soil during consolidation process.