• 한국세라믹학회지
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• 제44권11호
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• pp.633-638
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• 2007

The setting time of alkali activated slag cement tends to be much faster than ordinary Portland cement, and its compressive strength had been higher from the 1 day but became lower than that of the cement on the 28 days. According to the results of the surface observation, weight loss, compressed strength, and erosion depth tests on the sulphuric acid solution. It has been drawn that alkali activated slag cement has a higher sulphate resistance than ordinary Portland cement, and in particular, the alkali activated slag cement added 5 wt% alumina cement has little deterioration on the sulphuric acid solution. The reason why the alkali activated slag cement has higher sulphate resistance than other hardened cement pastes is that it has no $Ca(OH)_2$ reactive to sulphate ion, and there is little $CaSO_4{\cdot}2H_2O$ production causing volume expansion, unlike other pastes. And it is supposed that $Al(OH)_3$ hydrates with high sulphate resistance, which is produced by adding the alumina cement increases the sulfate resistance.

• 한국건축시공학회지
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• 제11권1호
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• pp.83-90
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• 2011

The purpose of this research is to investigate the effect of AFm formation on the stiffening process of cement paste. High and low alkali sulfate clinkers were used for the experiments. The flow and stiffening behavior of cement paste was investigated using modified ASTM C403 penetration resistance test and oscillatory shear rheology. X-ray powder diffraction (XRD) was used for phase identification associated with stiffening of the paste. It was found from the results that low alkali clinker mixture produced very strong premature stiffening whereas high alkali clinker mixture did not cause premature stiffening. This is because of the large amount of alkali sulfate present in the clinker. Addition of calcium and sodium chloride to the high alkali clinker mixture caused faster stiffening and set.

• 한국의류학회지
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• 제25권5호
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• pp.891-900
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• 2001

The purpose of this study were to evaluate the physical properties and dyeability of cellulase and alkali(NaOH, KOH) treated ramie/man-made fiber mixture fabrics. The mixture fabrics were plain weave made by rayon and polyester fiber as warp yarn, and ramie as weft yarn. The crease resistance, drape, tensile strength, and water absorbancy were measured for test fabrics. The K/S value of dyed fabrics were calculated using color difference meter. Also colorfastness to washing and sunlight of dyed fabrics were evaluated. The results obtained from this study were as follows: Thickness and weight per unit area of alkali treated two mixture fabrics(rayon/ramie, polyester/ramie) increased compared to those of untreated fabrics, but cellulase treated fabrics did not changed a little. And alkali treated rayon/ramie mixture fabrics showed more change than polyester/ramie mixture fabrics on the thickness and weight. Tensile strength and water absorbancy of cellulase treated fabrics decreased compared to those of untreated, but crease resistance increased. Crease resistance, tensile strength(warp direction), water absorbancy and drape of NaOH treated rayon/ramie mixture fabrics decreased compared to those of untreated, but tensile strength(weft direction) increased. Water absorbancy and drape of NaOH treated polyester/ramie mixture fabrics decreased compared to those of untreated, but crease resistance and tensile strength(weft direction) increased. Tensile strength of KOH treated two mixture fabrics increased compared to that of untreated, but water absorbancy and drape decreased. Total hand of cellulase and alkali treated rayon/ramie mixture fabrics was improved compared to untreated. Dyeability of treated mixture fabrics was increased compared to untreated.

• 한국세라믹학회지
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• 제29권1호
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• pp.35-40
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• 1992

Porous glass in the ZrO2-SiO2 system containing up to 30 mol% zirconia were prepared from the mixed solutions of Zr(O.nC3H7)4 and partially prehydrolyzed TEOS by the sol-gel method. Pore characteristics, physical properties and alkali resistance were investigated. The gels converted into the porous glass by heating at $700^{\circ}C$, it was found that the glass like skeleton was already made up in lower temperature regions. The specific surface area of the porous glass was 227 $m^2$/g, average mean pore size was about 19$\AA$ and porosity was 19.2%, pore characteristics and physical properties depended on heating temperature. Alkali resistance of the porous glass increased as the zirconia content increased, because of the appearance of Zr-enriched layer at glass surface.

• 대한환경공학회지
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• 제29권7호
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• pp.801-809
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• 2007

플라이 애쉬와 고로슬래그는 알칼리 활성화시 점착성의 시멘트성 물질로 전환될 수 있는 산업부산물로서, 이 같은 시멘트성 물질의 생산은 포틀랜드 시멘트 제조시보다 에너지 소비가 적고 이산화탄소 방출도 적다. 플라이 애쉬/슬래그 시멘트의 압축강도에 대한 알칼리 활성화 조건의 영향과 이 시멘트의 산 저항 특성을 평가하기 위해 실험을 수행하였다. 두 개의 알칼리 활성화 용액, 즉 수산화나트륨과 수산화나트륨 + 물유리가 사용되었다. 물유리 농도는 모든 실험에서 압축강도에 가장 큰 영향을 미치는 인자로 나타났다. 그 다음으로 중요한 인자는 수산화나트륨 농도와 양생 온도 순이었다. 황산과 염산에 대한 FC(플라이 애쉬 시멘트)와 FSC(플라이 애쉬/슬래그 시멘트)의 산 저항성은 포틀랜드 시멘트(PC)보다 월등히 좋았다.

• 대한환경공학회지
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• 제30권1호
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• pp.61-68
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• 2008

알칼리활성 플라이 애쉬 시멘트(AAFC)라 불리는 새로운 시멘트 물질을 이용하여 AAFC-콘크리트를 제조하였다. 알칼리활성 플라이 애쉬 시멘트를 사용하여 제조한 AAFC-콘크리트와 OPC-콘크리트에 대하여 산 침투, 염분, 탄산화, 동결 융해에 대한 영향과 SEM, XRD 분석을 수행하였다. 플라이 애쉬를 85$^{\circ}C$에서 24시간 동안 알칼리 활성화하여 제조한 AAFC-콘크리트(35 MPa)의 산 저항성은 OPC-콘크리트(35 MPa)보다 훨씬 뛰어난 것으로 나타났다. 또한 AAFC-콘크리트(35 MPa)는 염분용액, 탄산화 그리고 동결-융해와 같은 공격에 OPC-콘크리트(35 MPa)와 비슷한 저항성을 가지고 있는 것으로 나타났다.

• 한국건설순환자원학회논문집
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• 제9권4호
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• pp.650-657
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• 2021

광물질 혼화재를 자극하는 알칼리 활성화제는 고가의 소재이지만, 고 알칼리 성분의 산업부산물 대체하기 위해서는 제품성과 경제성을 모두 만족하여야 한다. 본 연구에서는 50MPa 이상의 고강도 콘크리트에 GGBFS의 알칼리 활성 반응을 위한 목적으로 LCD 제조 공정에서 발생하는 알칼리 산업부산물(LW)을 사용하였다. LW을 혼입한 콘크리트는 작업성이 다소 저하되었으나, 압축강도가 증진되는 특징이 있었다. ACI 209.2R-08 압축강도 모델식을 이용하여 분석하여 LW 혼입에 따른 강도계수의 변화를 비교하였다. 콘크리트의 내구성능 시험에서도 염화물 침투 저항성 및 탄산화 저항성에서 우수한 성능을 나타내었다. 단열온도 상승시험 결과에서는 LW를 혼입하면 초기 수화열이 빨라지는 효과가 있으나, 최종 단열온도상승량은 LW의 혼입 유, 무에 큰 영향을 받지 않았다.

• 한국세라믹학회지
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• 제45권11호
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• pp.719-724
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• 2008

Every concrete structure should continue to perform its intended functions such as to maintain the required strength and durability during its lifetime. Deterioration of the concrete structure, however, occurs more progressively from the outside of the concrete exposed to severe conditions. Main deteriorations in concrete structures result from carbonation, chloride ion attack and frost attack. Concrete can therefore be more durable by applying surface protection to increase its durability using impregnants, which are normally classified into two large groups in polymeric and silicate materials. Concrete impregnants are composed of silanes and alkali silicates (sodium, potassium and lithium silicate). Thus, this study is concerned with elevating the carbonation and Cl- penetration resistance of concrete structures by applying alkali silicate hydrophilic impregnants including lithium and potassium silicates. From the experimental test results, lithium and potassium silicates produced a good improvement in carbonation resistance and are expected to be used as hydrophilic impregnants of concrete structures.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.105-106
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• 2011

The present tests examined the resistance to freezing and thawing of alkail-activated (AA) slag concrete having compressive strength between 30~56 MPa. To enhance the compressive strength and resistance to freezing and thawing of AA slag concrete, Na ions were used for an activator. Test results revealed that the resistance to freezing and thawing of AA slag concrete is comparable to that of cement concrete when compressive strength is more than 50 MPa.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.189-192
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• 1998

The mechanical properties of alkali resistance (AR) glass fiber reinforced cement(GFRC) under different curing conditions were investigated in this study. The specimens were formed by extrusion process, and then steam cured and autoclaved. An autoclaved specimen showed the elastic-brittle behavior up to 4% of fiber volume fraction. However, it was found that the fracture behavior for cured specimen was changed to the elastic-plastic with crack branches fracture at greater than 3 vol.% of fiber.