• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.429-433
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• 2007

Cement mortar and concrete can be used as grouts but problems regarding shrinkage and the discord of coefficients of thermal expansion between grouts and HDPE pipes has to be solved. Thermal conductivities of wet condition two times larger than those of dry condition, except for pure cement mortar. The addition of sand into the cement grouts greatly increases the thermal conductivity. The addition of bentonite into the cement grouts reduces thermal conductivity thus reducing the density. Bentonite grouting must be used only below the groundwater table since bentonite grouts possesses high shrinkage property in dry condition. The addition of sand prevents the shrinkage of bentonite grouts. Bentonite manufactured in Korea can be used since they possess similar thermal conductivities with imported products. The addition of sand into the bentonite grouts greatly increases the thermal conductivity.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.323-326
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• 1999

The purpose of this study is to examine the properties of cement mortar with PVA(Poy Vinyl Alcohol) and MC(Methyl Cellulos). In this paper, Water-soluble polymer cement motar using PVA and MC with water-cement ratio of 50%, polymer-cement ratio of 1.0%, 0.8% and a ratio of cement to fine aggregate (size: #5, #7) 2:3 are prepared, and tested for compressive strength, shear bond strength, flow test, penetration and dry-shirinkage.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.319-322
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• 1999

The adhesion properties of polymer cement mortars for cement concrete repair were evaluated with respect to polymer-cement ratios and the surface conditions of cement concrete substrate. Styrene-butadiene rubber (SBR) was used as an additive for polymer cement mortars. The adhesion strength of cement mortar was smaller than that of polymer cement mortar. The adhesion strengths to the dry surfaces of substrate were larger than those to the wet surfaces, indicating that the dryness of substrate increased the adhesion strength in repairing concrete structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.138-143
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• 1993

The objective of this report is to investigate the effect of factors like the fineness modulus of sand , content of fly ash and slaked lime, binder/sand ratio, admixture dosage on the physical properties of mortar for finishing. The analysis was performed with design of experiment and air content, water retention and compressive strength were measured.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.273-277
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• 1995

This study presents the physical and adhesive properties of the top coated materials for concrete slab. i.e, cement based top coated materials. epoxy mortar. The purpose of this study offers the investigation of construction factors to affect the quality of the coated materials over hardened concrete. The experimental results shows that the water content 3% of sand decline the strength and adhesive properties of epoxy mortar, on the other hand, dry surface and curing for cement based material.

• Advances in materials Research
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• 제4권1호
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• pp.45-60
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• 2015

This paper aimed to investigate the effect of MWCNTs on properties of slag Geopolymeric mortar. Geopolymeric matrices containing different MWCNTs concentrations (0.0, 0.1, 0.2, 0.3 and 0.4 % by weight of the used binder) were synthesized. The Geopolymer mortar composed of aluminosilicate slag to sand (1:2), while the alumino silicate source binder composed of 50% air cooled slag and 50%water cooled slag both passing a sieve of $90{\mu}m$, while the sand passing a sieve of 1 ml. The materials prepared at water/binder ratios in a range of 0.34-0.39% depending on the added MWCNT, whereas the Gelenium Ace-30 superplasticizer used in the ratio of 1.4-2.2% from the total dry weight for better dispersion of MWCNT under sonication for 15 min. Alkaline activation of the Geopolymer mortar was carried by using of 6% NaOH. Curing was performed under temperature of $40^{\circ}C$ and 100% R.H. Results showed that the addition of MWCNTs enhanced the resulting amorphous geopolymer structure with marked decrease in the drying shrinkage as well as water absorption specially when using 0.1% MWCNT, while further increase in MWCNTs results in agglomeration in MWCNT within the matrix and so hinder the propagation of Geopolymerization reaction and negatively affect the formed geopolymer structure.

• Advances in concrete construction
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• 제10권6호
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• pp.537-546
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• 2020

Exterior walls in buildings are exposed to various forms of thermal loads, which depend on the positions of walls. Therefore, one of the efficient methods for improving the energy competence of buildings is improving the thermal properties of insulation plaster mortar. In this study, lightweight fine aggregate (LWFA) and micro rubber ash (MRA) from recycled tires were used as partial replacements for sand. The flow ability, unit weight, compressive strength, tensile strength, thermal conductivity (K-value), drying shrinkage and microstructure scan of lightweight rubberized mortar (LWRM) were investigated. Ten mixtures of LWRM were prepared as follows: traditional cement mortar (control mixture); three mixes with different percentages of LWFA (25%, 50% and 75%); three mixes with different percentages of MRA (2.5%, 5% and 7.5%); and three mixes consisting both types with determined ratios (25% LWFA+5% MRA, 50% LWFA+5% MRA and 75% LWFA+5% MRA). The flow ability of the mortars was 22±2 cm, and LWRM contained LWFA and MRA. The compressive and tensile strength decreased by approximately 64% and 57%, respectively, when 75% LWFA was used compared with those when the control mix was used. The compressive and tensile strength decreased when 5% MRA was used. By contrast, mixes with determined ratios of LWFA and MRA affected reduced unit weight, K-value and dry shrinkage.

• 한국건축시공학회지
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• 제24권1호
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• pp.1-10
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• 2024

In-situ 탄산화 기술은 시멘트 기반 건설재료의 제조과정에서 CO₂를 주입하여 시멘트 수화과정에서 용출되는 Ca²⁺ 이온과 CO₂의 탄산화 반응을 통해 CaCO₃의 형태로 CO₂를 격리하는 광물탄산화 기술이며, 본 연구에서는 현재 국내 건설현장에서 시공되고 있는 바닥용 건조시멘트 모르타르 배합의 범위에서 In-situ 탄산화 기술을 적용 시, CO₂의 주입 유량 및 총 주입량을 검토하고, 바인더인 단위시멘트량 감축에 따른 제품의 품질 검토를 실시하였다.

• 한국건설순환자원학회논문집
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• 제5권4호
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• pp.99-105
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• 2010

본 연구는 순환잔골재와 플라이애시 만을 사용하는 무 시멘트 모르터의 배합요인 변화가 모르터의 품질특성에 미치는 영향에 대하여 분석하였는데, 그 결과를 요약하면 다음과 같다. 굳지 않은 모르터의 특성으로 모르터 배합비 및 플로우치가 증가할수록 W/B는 높게 선정되었고, 공기량은 감소하는 경향을 나타내었다. 경화 모르터의 특성으로 재령 경과에 따른 압축강도는 14일 재령 이전까지는 강도를 발휘하지 못하다가, 이후 28일까지 재령이 경과함에 따라 약 1 ~ 2 MPa 정도의 강도값을 나타내었고, 28일 재령 이후에서는 거의 유사한 강도값을 나타내었다. 또한, 배합비 및 플로우치, B/W 변화에 따른 압축강도는 전반적으로 유사한 강도값을 나타내었다. 이상의 실험 결과를 종합하면, 순환잔골재와 플라이애시를 사용한 모르터의 경우 구조체용으로는 부적합할지라도 지반 매립재 용도로는 적합할 수 있는 강도를 확보하였는데, 특히 부배합보다는 빈배합 영역일수록 우수한 활용성이 입증되었다.

• Advances in concrete construction
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• 제9권5호
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• pp.449-457
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• 2020

The influence of subsequent curing on the performance of fly ash contained mortar under steam curing was studied. Mortar samples incorporated with different content (0%, 20%, 50% and 70%) of Class F fly ash under five typical subsequent curing conditions, including standard curing (ZS), water curing(ZW) under 25℃, oven-dry curing (ZD) under 60℃, frozen curing (ZF) under -10℃, and nature curing (ZN) exposed to outdoor environment were implemented. The unsteady chloride diffusion coefficient was measured by rapid chloride migration test (RCM) to analyze the influence of subsequent curing condition on the resistance to chloride penetration of fly ash contained mortar under steam curing. The compressive strength was measured to analyze the mechanical properties. Furthermore, the open porosity, mercury intrusion porosimetry (MIP), x-ray diffraction (XRD) and thermogravimetric analysis (TGA) were examined to investigate the pore characteristics and phase composition of mortar. The results indicate that the resistance to chloride ingress and compressive strength of steam-cured mortar decline with the increase of fly ash incorporated, regardless of the subsequent curing condition. Compared to ZS, ZD and ZF lead to poor resistance to chloride penetration, while ZW and ZN show better performance. Interestingly, under different fly ash contents, the declining order of compressive strength remains ZS>ZW>ZN>ZD>ZF. When the fly ash content is blow 50%, the open porosity grows with increase of fly ash, regardless of the curing conditions are diverse. However, if the replacement amount of fly ash exceeds a certain high proportion (70%), the value of open porosity tends to decrease. Moreover, the main phase composition of the mortar hydration products is similar under different curing conditions, but the declining order of the C-S-H gels and ettringite content is ZS>ZD>ZF. The addition of fly ash could increase the amount of harmless pores at early age.