• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.199-204
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• 1998

To analysis the failure character of Low-Heat concrete which is used to prevent the thermal crack caused by hydration heat, static loading test was performed by this test method, "Determination of the Fracture Energy of Motar and Concrete by Means of Three-Point Band Tests on Notched Beam" (suggested by RILEM 50-FMC Committe). This study compared and analysised the fracture energy of Mode I (opening mode), the most general pattern in the view of water-cemente ratio(W/C), compressive strength and age of Ordinary Portland Concrete and Low-Heat Concrete under the same mixture. The test results show that the case of Ordinary Portland Concrete and Low-Heat Concrete, low Water-Cemente ratio(W/C) cause the increase of fracture energy, and high failure-strength decrease failure-deflection, and the fracture energy of Low-Heat Concrete is similar to Ordinary Portland Concrete as the age increase. increase.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.477-478
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• 2010

Concretes with binary blends of Portland cement, silica fume, fly ash and ground granulated blast furnace slag were produce to investigate their effects on compressive strength and chloride transport in rapid chloride permeability. Ten different mix of concrete with 0.45 water/binder were produced. Portland cement was replacedby: (i) 10%, 20%, 30% Fly ash (ii) 3%, 5%, 10% Silica Fume (iii) 20%, 40%, 60% GGBS. Compressive strength of concrete with the pozzolans is higher compared to that of the Portland cement concrete. The test results indicate the fly ash, silica fume, and ground granulated furnace slag greatly reduce the rapid chloride permeability of concrete. It was concluded that pozzolans are more effective to reduce chloride permeability of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.335-336
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• 2010

POFA(Palm oil fuel ash)는 Palm fiber 와 shell의 부산물로써 콘크리트용 혼화재로 사용이 가능하다. 그러나 POFA를 사용한 콘크리트의 포졸란 반응에 관한 연구는 매우 적다. 따라서 본 연구에서는 다른 콘크리트용 혼화재료와 동일한 수준으로 POFA의 혼입 치환율을 달리한 모르타르의 압축강도 및 활성도 지수, 포졸란 활성도 지수(API)를 정량적으로 평가하여 혼화재료로서의 적합성을 평가하였다.

• Computers and Concrete
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• 제5권1호
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• pp.75-88
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• 2008

This paper presents a mathematical model for strength and porosity of mortars made with ternary blends of ordinary Portland cement (OPC), ground rice husk ash (RHA) and classified fly ash (FA). The mortar mixtures were made with Portland cement Type I containing 0-40% FA and RHA. FA and RHA with 1-3% by weight retained on a sieve No. 325 were used. Compressive strength and porosity of the blended cement mortar at the age of 7, 28 and 90 days were determined. The use of ternary blended cements of RHA and FA produced mixes with good strength and low porosity of mortar. A mathematical analysis and two-parameter polynomial model were presented for the strength and porosity estimation with FA and RHA contents as parameters. The computer graphics of strength and porosity of the ternary blend were also constructed to aid the understanding and the proportioning of the blended system.

• 한국세라믹학회지
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• 제28권11호
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• pp.917-925
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• 1991

For the present experiment five Portland cement mortars are in order: mortars with two different water/ cement ratios (W/C=0.45 and 0.50, each having no chemical additive), and those with an additive such as superplasticizer, air-entraining agent or water-repelling agent. We fix the W/C ratio of mortars having additive so that their pastes can yield the same workability as that of the cement mortar of W/C=0.50 with no additive. It is shown that the freeze-thaw resistivity depends heavily on the characteristic of wide pores. Despite a good deal of wide pores, the air-entrained specimen shows a good freeze-thaw resistivity due to appropriate air-pores. And also the specimen with water-repelling agent, which proves to cause the microstructure to become hydrophobic, make good resistance to freeze-thaw cycles in spite of its high wide-porosity. Our suggestion is that the freeze-thaw durability of Portland cement mortar/concrete can be more effectively enhanced by using air-entraining agent or water-repelling agent, and simutaneously by taking proper measures against foaming and/or the increased tendency of wide-pore building due to additive.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.189-190
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• 2018

This study produced Portland limestone cement at the rate of limestone substitution by grinding limestone and clinker together, and it conducted an XRD analysis to determine the sign language response structure as a basic study on Portland Limestone Cement. As a result of the XRD analysis, the higher the substitution rate of limestone, the more likely it is that the detection rate of ettringite is decreased. Additionally, we could see that the production volume of Mono-carbonate was increasing.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1211-1214
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• 2000

The purpose of this paper was to study of blast furnace slag cement of high early strength and replacement ordinary portland cement. we prepared the specimens of cement and concrete with various mixing proportions of elementary materials. For example, clinker, gypsum(1~10%), fineness $4, 000~6, 000cm^2/g$ of blast furnace slag(30~50%), limestone etc. As a result of this study, fineness $(4, 000cm^2/g)$ blast furnace slag was of used replacement ordinary portland cement and fineness $(6, 000cm^2/g)$ blast furnace slag was of used blast furnace slag cement of high early strength.

• 한국세라믹학회지
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• 제25권2호
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• pp.101-110
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• 1988

In order to improve the physical properties of concrete used for treatment and disposal container of low-and intermediate-level radioactive wastes, OPC (ordinary portland cement), ACPC (asphalt coated portland cement) and EPC(epoxy-portland cement) concrete specimens were prepared, and the physical properties of each concrete specimen were tested. According to the experimental results, EPC concrete showed better physical properties than ACPC and OPC concrete, however, ACPC concrete proved to be a best material for treatment and disposal container of radwastes in view of economic aspect and physical properties.

• Computers and Concrete
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• 제13권6호
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• pp.695-707
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• 2014

This study investigated the chloride binding isotherms of various cement types, especially the contributions of C-S-H and AFm hydrates to the chloride binding isotherms were determined. Ordinary Portland cement (OPC), Modified cement (MC), Rapid-hardening Portland cement (RHC) and Low-heat Portland cement (LHC) were used. The total chloride contents and free chloride contents were analyzed by ASTM. The contents of C-S-H, AFm hydrates and Friedel's salt were determined by X-ray diffraction Rietveld (XRD Rietveld) analysis. The results showed that OPC had the highest chloride binding capacity, and, LHC had the lowest binding capacity of chloride ions. MC and RHC had very similar capacities to bind chloride ions. Experimental equations which distinguish the chemically bound chloride and physically bound chloride were formulated to determine amounts of the bound chloride basing on chloride binding capacity of hydrates.

• Computers and Concrete
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• 제10권4호
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• pp.349-360
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• 2012

In this paper, compressive strength, water permeability and abrasion resistance of concretes containing high volume fine fly ash (FFA) and fine ground palm oil fuel ash (GPA) were studied. Portland cement type I was replaced with FFA and GPA at dosages up to 70% by weight of binder. Ground river sand (GRS) was also used to replace Portland cement in order to indicate the level of filler effect. Results indicated that FFA was slightly more reactive than GPA. The replacement of 40-70% of FFA produced concretes with compressive strength, permeability and abrasion resistance comparable to those of normal concretes. The incorporation of GPA slightly reduced the performances of concretes as compared to those of FFA concretes. The reduction of Portland cement was partly compensated by the increase in pozzolanic activity of the fine fly ash and palm oil fuel ash and thus enabled the large replacement levels.