• 제목/요약/키워드: replacement ratios

검색결과 288건 처리시간 0.031초

심장판막수술 후 프로트롬빈 INR 모니터링형 자가관리프로그램 개발 및 적용 (Development and Application of a Self-management Program based on Prothrombin INR Monitoring for Patients with Cardiac Valve Replacement)

  • 전현례;박정숙
    • 대한간호학회지
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    • 제45권4호
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    • pp.554-564
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    • 2015
  • Purpose: The purpose of this study was to develop and evaluate a self-management program based on INR monitoring for patients with cardiac valve replacement. Methods: This program was comprised of five weekly sessions based on Sousa's Enhance-Behavior Performance Model. The first session included individual teaching, and the other four sessions included Prothrombin Time International Normalized Ratios (PT INR) self-monitoring, telephone counseling and self-management checklist recording. Participants were patients who had cardiac valve replacement. They were randomly assigned to the experimental or control group. Sixteen in the experimental group participated in the self-management program and seventeen in the control group participated in general care. Self-management knowledge, self-efficacy, self-management behavior and PT INR were measured as dependent variables. Data were analyzed using Mann Whitney U-test, t-test and ANCOVA. Results: The experimental group showed significantly higher post-test scores in self-management knowledge (t=5.86, p<.001), self-efficacy (F=18.32, p<.001), and self-management behavior (t=3.44, p=.002) compared to the control group. Also, the experimental group showed significantly higher frequency in maintaining the treatment range of PT INR compared to the control group (${\chi}^2=4.80$, p=.028). Conclusion: The results of the research on the self-management program based on PT INR monitoring showed that it is effective in improving self-management knowledge, self-efficacy, and self-management behavior as well as maintaining treatment range of PT INR of patients with cardiac valve replacement.

저열 시멘트 HVFAC 강도 발현 특성 (The Characteristics of Strength Development on Concrete with Low Heat Cement and High Volume Fly-Ash)

  • 박찬규;이승훈;김한준;김상준;이태왕
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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    • pp.637-640
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    • 2008
  • 본 연구에서는 플라이애쉬가 다량 치환된 콘크리트 강도 발현과 수화열 특성에 대하여 연구를 수행하였다. 3수준의 W/B와 4수준의 플라이애쉬 치환률 및 2수준의 실리카흄 치환율을 실험 변수로 선택하였다. 콘크리트 배합에서 단위수량은 125kg/m$^3$으로 고정하였다. 결과로서 초기 재령에서는플라이애쉬 치환율이 증가하면서 재령 91일까지 압축강도가 점진적으로 감소하는 경향을 나타내었다. 그런데 강도를 고려하면, 적절한 플라이애쉬 치환율은 20%인 것으로 나타났는데, 이는 제 1종시멘트의 경우에 비하여 낮은 값이다. 콘크리트의 인장강도는 압축강도의 0.72승에 비례하는 것으로 나타났다. 그리고 콘크리트 표준 시방서에 제시되어 있는 인장 강도 식은 압축강도가 낮은 경우에과대평가하고, 압축강도가 높은 경우에 과소평가하는 것으로 나타났다.

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폴리머 디스퍼션을 이용한 프리팩트 콘크리트용 주입 모르타르의 배합에 관한 연구 (Mix Design of Polymer Grouting Mortar for Prepacked Concrete Using Polymer Dispersions)

  • 조영국;김완기
    • 한국건축시공학회지
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    • 제8권5호
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    • pp.85-91
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    • 2008
  • Prepacked concrete has recently been used in the special constructions fields such as underwater concrete work, heavy-weight concrete work, underground structure work, partial repair works for damaged reinforced concrete structures. and polymer-modified mortars have been employed as grouting mortars for the prepacked concrete. The purpose of this study is to recommend the optimum mix design of polymer-modified grouting mortars for prepacked concrete. Polymer-modified mortars using SBR and EVA emulsions as admixture of grouting mortars for prepacked concrete are prepared with various mix proportions such as sand-binder ratio, fly ash replacement ratio, polymer-binder ratio. and tested for flowability, viscosity of grouting mortars, bleeding ratio, expansion ratio, flexural and compressive strengths of grouting mortars and compressive and tensile strengths of prepacked concretes. From the test results, it is apparent that polymer-modified mortars can be produced as grouting mortars when proper mix design is chosen. We can design the mix proportions of high strength mortars for prepacked concrete according to the control of mix design factors such as type of polymer, polymer-binder ratio, sand-binder ratio and fly ash replacement ratio. Water-binder ratio of plain mortars for a constant flowability value are in the ranges of 43% to 50%. SBR-modified mortar has a little water-binder ratios compared to those of plain mortar, however, EVA-modified mortar needs a high water-binder ratio due to a high viscosity of polymer dispersion. The expansion and bleeding ratios of grouting mortars are also controlled in the proper value ranges. Polymer-modified grouting mortars have good flexural. compressive and tensile strengths, are not affected with various properties with increasing fly ash replacement to cement and binder-sand ratio. In this study, SBR-modified grouting mortar with a polymer-binder ratio of 10% or less, a fly ash replacement of 10% to cement and a sand-binder ratio of 1.5 is recommended as a grouting mortar for prepacked concrete.

현장재하시험을 통한 쇄석다짐말뚝의 응력분담에 관한 연구 (A Study on the Stress Concentration of Crushed-stone Compaction Piles through Field Loading Test)

  • 이민희;최용규;임종철;황근배
    • 한국지반공학회논문집
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    • 제19권6호
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    • pp.107-114
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    • 2003
  • 국내에서는 조립토를 이용한 연약지반 처리공법 중 모래다짐말뚝공법이 많이 활용되고 있으나, 모래자원의 고갈과 단가상승으로 인해 적용이 제한되고 있어 대체공법이 필요한 실정이다. 본 연구에서는 육상부 현장에 시험시공된 쇄석다짐말뚝에 대한 정재하시험을 수행하였으며, 쇄석다짐말뚝과 연약지반의 응력분담비를 규명하고 성능을 평가하였다. 임의 압력에서 치환율이 증가할수록 침하량이 작아지는 경향을 보였다. 치환율 20%일 때의 항복압력은 치환율 30%, 40%일 때 보다 작았다. 치환율 30%와 40%일 때의 항복응력과 침하량은 비슷하였다. 응력분담비는 1.7∼-3.0의 범위에 있었으며, 치환율이 증가할수록 응력분담비가 증가하는 경향을 보이고 있었다.

혼화재 종류 및 치환율에 따른 고강도콘크리트의 중성화와 건조수축에 관한 실험적 연구 (An experimental study on the Carbonation and Drying Shrinkage of High Strength Concrete Acording to Kinds and Ratios of Mineral Admixtures)

  • 권영진
    • 한국건축시공학회지
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    • 제3권3호
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    • pp.127-133
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    • 2003
  • Carbonation and drying shrinkage are very important properties of concrete, that can cause concrete to lower its capacity and spall. But the research on them in high strength concrete is very poor. In this study, to estimate influences of W/B, the kind of admixture, the replacement ratio of admixture, fineness of blast furnace and etc. on drying shrinkage and carbonation, we make experiment with 3 levels(28, 35, 55%) of W/B, 3 kinds(blast-furnace slag, fly-ash, silica-fume) of admixture, 3 levels of the replacement ratio, 3 levels(4000, 6000, 8000cm2/g) of fineness of blast-furnace slag and 2 kinds of curing condition. As the results, compressive strength of concrete was decreased, as W/C was increased and the replacement ratio of admixture was increased. Drying shrinkage was increased, as W/B was higher, the replacement ratio of admixture was increased and fineness of blast-furnace slag was decreased. And carbonation was increased, as W/B ratio was higher, the replacement ratio of admixture was increased.

폐콘크리트 슬러지를 혼합 사용한 시멘트 모르터의 기초 특성 (Fundamental Properties of Cement Mortar with Waste Concrete Sludge)

  • 이명진;이하나;유재성;김진만
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2015년도 추계 학술논문 발표대회
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    • pp.160-161
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    • 2015
  • This research reviewed the characteristics of waste concrete sludge occurred from recycled aggregate producing process and the physical and mechanical properties of the mortar incorporated the pulverized the waste concrete sludge. From the results of the experiment, as the replacement ratio of waste concrete sludge powder was increased, the dosage of superplasticizer to satisfy the target flow of 200 ± 10 was increased, and the compressive and flexural strengths were decreased. On the other hand, when the sludge powder replacement ratio was 25 %, outstanding performance of general characteristics of mortar was obtained while it was lower than Plain mixture, thus, further detail study on various replacement ratios of waste concrete sludge powder is needed.

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무기질 혼화재 및 금속비누의 혼입률 변화에 따른 시멘트 모르터의 방수 특성에 관한 연구 (A Study on the Waterproof Properties of Cement Mortar with the Addition Rate of the Inorganic Admixture and Zinc Stearate)

  • 최훈;강의영;한민철;류현기;한천구
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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    • pp.139-144
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    • 1998
  • This study is intended to devolop the self waterproof agents for high performance concrete by analyzing the properties of fresh and hardened mortar with various addition ratios of the inorganic admixture and zinc stearate. As the results of the test, the flow and air content increase with the addition of expansive additives. When the replacement rate of silica fume increases, the flow decreases for the increased viscidity. And the flow and sir content decrease with the addition of zinc stearate. At hardened state, the compressive strength, tensile strength and flexual strength decrease with the addition of expansive additives and zinc stearate. With the increase of silica fume's replacement, they show a little decrease at early age and then increase gradually. Also, absorption and permeability show a steep decrease when zinc stearate is added, and a slack decrease with the replacement of silica fume.

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고로슬래그 미분말 치환에 따른 알칼리-실리카 반응 팽창 저감효과 (The Effect of Ground Granulated Blast Furnace Slag Replacement on Alkali -Silica Reaction)

  • 김지현;전쌍순;엄장섭;진치섭
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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    • pp.431-434
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    • 2005
  • The effect of ground granulated blast furnace slag to prevent detrimental expansion due to alkali-silica reaction was investigated through the ASTM C 1260 method. This method is one of the most commonly used method because results can be obtained within 16 days. Reactive aggregate used is a metamorphic rock. The replacement ratios of portland cement by ground granulated blast furnace slag were 0, 15, 25, 35 and 55 percent, respectively. The results indicate that 35 percent replacement of portland cement by ground granulated blast furnace slag seems to be effective to reduce alkali-silica reaction expansion under this experimental conditions.

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폐내화물 미분말 치환율이 고로슬래그 미분말과 순환골재 사용 모르타르의 품질에 미치는 영향 (Influence of Replacement Ratio of Wasted Refractory Powder on the Properties of Mortar using Blast Furnace Slag and Recycled Aaggregate)

  • 송원루;백철;김민상;이제현;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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    • pp.38-39
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    • 2016
  • In this research, the possibility of wasted refractory powder pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory powder was replaced 10 %.

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폐내화물 골재 치환율이 고로슬래그 미분말과 순환골재 사용 모르타르의 품질에 미치는 영향 (Influence of Replacement Ratio of Wasted Refractory Aggregate on the Properties of Mortar using Blast Furnace Slag and Recycled Aggregate)

  • 송원루;문병룡;김민상;이제현;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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    • pp.139-140
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    • 2016
  • In this research, the possibility of wasted refractory aggregate pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory aggregate was replaced 2%.

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