• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.116-124
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• 2015

본 연구는 폴리머 기반 보수모르타르에 미분쇄된 플라이애시 치환율의 영향을 평가하였다. 주요변수는 양생온도와 미분쇄된 플라이애시의 치환율이다. 양생온도는 $40^{\circ}C$, $20^{\circ}C$ 및 $5^{\circ}C$로, 미분쇄된 플라이애시 치환율은 결합재 대비 0~35%로 변화하였다. 굳지 않은 모르타르에서는 플로우를, 굳은 모르타르에서는 재령별 압축강도, 응력-변형률 관계 및 탄성계수, 파괴계수를 측정하고, 주사전자현미경 및 엑스선회절기 분석을 수행하였다. 실험결과 보수모르타르의 플로우, 탄성계수 및 파괴계수는 미분쇄된 플라이애시 치환율 20~30%에서 가장 높은 성능을 발휘하였다. 또한 재령별 압축강도는 미분쇄된 플라이애시 치환율과 양생온도에 현저한 영향을 받았는데, 미분쇄된 플라이애시 치환율 20%에서 초기강도 발현율이 가장 높았다. ACI 209에서 제시하고 있는 콘크리트 재령별 압축강도예측모델에서 초기 및 장기재령 강도발현 계수는 미분쇄된 플라이애시 치환율과 양생온도의 함수로 일반화할 수 있었다. 미분쇄된 플라이애시가 첨가된 페이스트는 수화생성물을 나타내는 피크(peak)의 수와 강도(intensity)가 증가되고 플라이애시 입자주변에 CSH 겔이 형성되었다.

• Elastomers and Composites
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• 제48권2호
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• pp.133-140
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• 2013

탄소섬유강화 고분자(CFRP) 복합재료는 고분자 매트릭스 내에 탄소섬유를 강화제로 사용한 복합재료이다. 최근 고온 및 고진공 조건이 요구되는 항공우주 및 전자산업용 고성능 재료로 사용하기 위해 높은 열안정성과 낮은 기체방출 특성을 갖는 CFRP 복합재료가 활용되고 있다. 이러한 용도에 시아네이트 에스터 수지는 가장 적합한 매트릭스 수지로 꼽히고 있다. 본 연구에서는 시아네이트 에스터 수지와 촉매의 조합, 경화 거동 및 경화 사이클을 최적화하기 위해 화학유변학적 거동을 분석하였다. 최적 조건은 촉매 100 ppm을 첨가한 수지 조성물을 $150^{\circ}C$에서 경화한 경우로 나타났다. 열안정성과 기체방출 특성을 분석한 결과 경화된 수지 조성물은 열분해 온도 $385^{\circ}C$ 및 전체질량손실 0.29%를 나타내었다. 설정한 수지 조성 및 경화 조건을 사용하여 CFRP 프리프레그 및 이를 적층한 복합재료를 제조하였다. 복합재료의 인장 탄성률을 이론적 모델과 비교한 결과 매우 일관성이 있었다.

• Macromolecular Research
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• 제12권3호
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• pp.282-289
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• 2004

We have extensively characterized the fluorescence behavior of unsaturated polyester (UP) resin in the absence and presence of a 1,3-bis-(l-pyrenyl)propane (BPP) fluorescent probe at various dynamic and isothermal cure histories by means of a steady-state fluorescence technique using a front-face illumination equipment. In addition, we explored the effect of the fluorescence intensity on the relaxation of the fluorescent probe in the UP resin by resting the dynamically and isothermally cured resin at ambient temperature and pressure for 24 h. The monomer fluorescence intensity, which has two characteristic peaks at 376 and 396nm, changed noticeably depending on the cure temperature and time and provided important information with respect to the molecular and photophysical responses upon curing. The result of the fluorescence study indicates that the increased local viscosity and restricted molecular mobility of the UP resin surrounding the BPP probe after curing are both responsible for the enhancement of the monomer fluorescence intensity. Our results also demonstrate that once the BPP probe has enough time to rearrange and become isolated prior to fluorescence, a sufficient amount of fluorescence is emitted. Therefore, we note that the fluorescence behavior of this UP resin system is influenced strongly by the relaxation process of the fluorescent probe in the resin as well as process used to cure the resin.

• 대한소아치과학회지
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• 제30권2호
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• pp.245-253
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• 2003

치과용 복합레진의 중합률은 레진 기질내의 이중결합의 전환도를 나타내는 것으로 이는 재료의 물리적 성질과 기계적 성질 및 생체 친화성에 영향을 미친다. 레진의 중합도가 증가하면 취성과 수축이 증가하고 중합도가 낮으면 기계적 물리적 성질이 감소한다. 따라서 본 연구에서는 광중합형 복합레진을 사용하여 플라즈마 아크 중합기 2종, 할로겐 중합기 2종, LED 중합기 2종, pulse-delay curing의 서로 다른 중합방법의 경우를 FTIR 분석법으로 복합레진의 물리적 기계적 성질 및 생체친화성에 영향을 미치는 중합률을 분석하여 다음과 같은 결과를 얻었다. 1. 광중합 복합레진의 중합률은 FTIR로 측정하였을 때 34.52-49.31%사이로 나타났으며 플라즈마 아크 중합의 경우 Flipo는 $39.96{\pm}1.22%$, CrediII는 $45.64{\pm}1.34%$로, 할로겐 중합시 XL3000은 $43.48{\pm}1.34%$, VIP의 mode 4 사용시는 $44.31{\pm}0.72%$, LED의 LUXOMAX는 $49.31{\pm}2.37%$, Elipar Freelight는 $44.51{\pm}0.62%$, pulse-delay curing시에는 $34.52{\pm}0.85%$로 나타났다. 2. 각 중합 방법별로 중합률은 LED 중합 방법을 이용한 LUXOMAX가 다른 실험군에 비하여 가장 높은 중합률을 나타냈으며 pulse-delay curing 방법이 가장 낮은 중합률을 보였다. 3. Flipo 중합기, LUXOMAX 중합기, pulse-delay curing 방법이 다른 중합기와 비교하여 통계적으로 유의한 차이를 보였다(p<0.05). 4. 각 중합방법이 동일한 군 내의 중합기기별 차이에서는 할로겐에서는 광중합기 사이에 중합률의 차이를 보이지 않았으나 플라즈마 아크에서는 CrediII가, LED에서는 LUXOMAX가 중합률이 높았다(p<0.05).

• 한국농공학회지
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• 제39권2호
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• pp.44-50
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• 1997

Permeable polymer concrete can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc.. This study was to explore a possibility of using stone dust and heavy calcium carbonate as fillers for the permeable polymer concrete. Different mixing pro-portions were tried to find an optimum mixing proportion of the permeable polymer concrete. The tests were carried out at 20 f 1 t and 60 ${\pm}$ 2% relative humidity. At 7 days of curing, compressive, flexural and splitting tensile strengths and water permeability ranged between 209~246kgf/cm$^2$, 101 ~ l2lkgf/cm$^2$, 36~52kgf/cm$^2$ and 3.076 ~ 4.390L/cm$^3\;^2$/hr, respectively. It was concluded that the stone dust and heavy calcium carbonate could be used in the permeable polymer concrete.

• 한국농공학회논문집
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• 제47권4호
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• pp.25-32
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• 2005

This study was performed to evaluate the strength properties of polymer concrete using recycled aggre-gate. The compressive strength, splitting tensile strength, flexural strength and pulse velocity of polymer concrete were decreased with increasing the content of recycled aggregate. At the curing age of 7days, the compressive strength was $80.5\~88.3$ MPa, the splitting tensile strength was $9.1\~10.6$ MPa, the flexural strength was $19.2\~21.5$ MPa and the pulse velocity was $3,931\~4,041$ m/s, respectively. Also, the compressive strength, splitting tensile strength, flexural strength and pulse velocity of concrete using recycled fine aggregate were higher than that of the silica sand. Therefore, these recycled aggregate polymer concretes were estimated for high strength concrete without major problem.

• 한국농공학회논문집
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• 제48권7호
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• pp.25-31
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• 2006

Permeable polymer concretes can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study was to explore a possibility of using bottom ash as filler and recycled coarse aggregate of industrial by-products for permeable polymer concrete. The tests carried out at $20{\pm}1^{\circ}C$ and $60{\pm}2%$ relative humidity. At 7 days of curing, unit weight, void ratio, compressive and flexural strength and coefficient of permeability ranged between $1,652{\sim}1,828kgf/m^{3},\;15{\sim}29+%,\;18.2{\sim}24.5\;MPa,\;6.4{\sim}8.4\;MPa\;and\;6.8{\times}10^{-2}{\sim}1.7{\times}10^{-1}\;cm/s$, respectively. It was concluded that the bottom ash and recycled coarse .aggregate can be used in the permeable polymer concrete.

• 농업과학연구
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• 제37권1호
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• pp.87-96
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• 2010

This study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks that were manufactured by using recycled coarse aggregates and unsaturated polyester resin to develop environmentally friendly planting blocks. Unsaturated polyester resin, natural and recycled coarse aggregates and $CaCO_3$ were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes(5-10 and 5-20mm). Tests for the void ratio and compressive strength of porous polymer concrete were performed at curing age 7 days. Also, porous polymer block using recycled coarse aggregates were applied to kinds of plants such as tall fescue, Perennial ryegrass, Lesedeza and Alfalfa. After seed, initial germination, germination ratio, cover view and growth length for planting blocks were estimated by various methods.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.723-726
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• 2004

Porous polymer concrete can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study is to examine a content ratio of polypropylene fiber to improve bending strength, impact resistance and freezing and thawing rssistance of porous polymer concrete. Also, this study is performed to develop the porous polymer concrete using recycled coarse aggregate and blast furnace slag for application of structures needed permeability. At 7 days of curing, compressive strength, flexural strength, water permeability and flexural load are in the ragge of $17\~21MPa,\;5\~7MPa,\;4.1\times10^{-2}\~7.7\times10^{-2}cm/s$, respectively. It is concluded that the recycled aggregate can be used in the porous polymer concretes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.117-122
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• 2001

Recently, epoxy-coated re-bar used to the structure partly and put to practical use step, but not economical and appeared to the defect of deterioration of long term bond strength between concrete. The method for complement the defect of epoxy coated re-bar, study of polymer cement slurry coated re-bar started and basic properties appeared to excellent, but study of bond properties embedded in concrete specimens insufficient until now. This study attempts to examination of using possibility for bond strength of polymer cement slurry coated re-bar between concrete specimens compare to ACI Code and KS Code through pull-out test of 15cm$\times$15cm$\times$15cm specimens with polymer cement slurry coated re-bar as polymer cement ratio 50%, 100%, 150%, coating thickness 250${\mu}{\textrm}{m}$, 440${\mu}{\textrm}{m}$ and curing age. In the results of this study, the bond strength of polymer cement slurry coated re-bar compare to plain re-bar, epoxy coated re-bar decreased St/BA-modified polymer cement slurry coated re-bar, but bond strength of PA-modified polymer cement slurry coated re-bar appeared to excellent results. The bond properties of polymer cement slurry coated re-bar between concrete will be obtain more precise results according to compressive strength change of concrete and re-bar diameter size.