• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.213-214
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• 2010

An objective of this experimental research is to investigate the diffusion characteristics for chloride ion of concrete subjected to sulfate attack. For this purpose, concretes with three types of cement such as ordinary portland cement(OPC), binary blended cement(BBC), and ternary blended cement(TBC) containing mineral admixtures were made for water-binder ratios of 32% and 43%. The concrete specimens were immersed in sulfate solution for 365 days, and then the resistance against chloride ion penetration of them were estimated by using NT BUILD 492. It was observed from the test results that the resistance to chloride ion penetration of concrete subjected to sulfate attack was greatly decreased than that of standard curing concrete under the same age.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.517-520
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• 2008

In this study, corrosion resistance of steel in cracked-reinforced concrete was performed according to experimental method. Mixed design is OPC, 30% PFA, 60% GGBS and 10% SF, respectively. Moreover, corrosion resistance test was measured using ultra testing machine for 0.3mm crack induction. The corrosion resistance of blended concrete shows the results following OPC > 10%SF > 30% PFA > 60% GGBS after 60days curing. In case of mass loss test, embedded reinforcement in OPC concrete surveyed the minimum corrosion and appeared better corrosion resistance than blended concrete. As a result, corrosion resistance of sound concrete is higher than cracked concrete. Moreover, corrosion resistance of binary concrete is lower than OPC.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.573-576
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• 2006

To predict service life of concrete structures exposed to chloride attack, surface chloride concentration, diffusion coefficient of chloride ion, and chloride corrosion threshold value in concrete, are used as important factors. of these, as the diffusion coefficient of chloride ion for concrete is strongly influenced by concrete quality and environmental conditions of structures and may significantly change the service life of structures, it is considered as the most important factor for service life prediction. The qualitative factors affecting the penetration and diffusion of chloride ion into concrete are water-binder(W/B) ratio, age, cement type and constituents, chloride ion concentration of given environment, wet and dry conditions, etc. In this paper the influence of cement type on the diffusion characteristics of chloride ion in concrete was investigated through the chloride ion diffusion test. For this purpose, the diffusion characteristics in concrete with cement type such as ordinary portland cement(OPC), binary blended cement(BBC), and ternary blended cement(TBC) were estimated for the concrete with W/B ratios of 32% and 38%, respectively. It was observed from the test that the difussion characteristics of BBC containing OPC and ground granulated blast-furnace slag was found to be most excellent of the cement type used in this study.

• Fibers and Polymers
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• v.5 no.4
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• pp.264-269
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• 2004

The present paper deals with improvement in disperse dyeablility as well as imparting of cationic dyeablility to difficultly dyeable polypropylene by a melt blending technique. Isotactic polypropylene (PP) was blended with fibre grade polybutylene terephthalate (PBT), cationic dyeable polyethylene terephthalate (CDPET) and polystyrene (PS), individually. The resulting binary blends were spun and drawn into fibres at draw ratio 2, 2.5, and 3. The compatibility of blends, structural changes of fibres in terms of X-ray crystallinity, relative crystallinity, sonic modulus, birefringence and thermal stability were examined. The blended fibres were found to be disperse dyeable by the conventional method of high temperature and high pressure dyeing. And this dye ability increased with increase in the level of substitution. PP/CDPET blend also exhibited dyeablility with cationic dyes in addition to that with disperse dyes. The optimum level of blending was predicted keeping in view of tenacity and thermal stability of melt blend fibres. The wash fastness properties of the dyed fibres were found to be of high rate.

• International Journal of Concrete Structures and Materials
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• v.7 no.3
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• pp.239-249
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• 2013

In the present scenario to fulfill the demands of sustainable construction, concrete made with multi-blended cement system of OPC and different mineral admixtures, is the judicious choice for the construction industry. Silica fume (SF) and fly ash (FA) are the most commonly used mineral admixtures in ternary blend cement systems. Synergy between the contributions of both on the mechanical properties of the concrete is an important factor. This study reports the effect of replacement of OPC by fly ash (20, 30, 40 and 50 % replacement of OPC) and/or silica fume (7 and 10 %) on the mechanical properties of concrete like compressive strength and split tensile strength, with three different w/b ratio of 0.3, 0.4 and 0.45. The results indicate that, as the total replacement level of OPC in concrete using ternary blend of OPC + FA + SF increases, the strength with respect to control mix increases up to certain replacement level and thereafter decreases. If the cement content of control mixes at each w/b ratio is kept constant, then as w/b ratio decreases, higher percentage of OPC can be replaced with FA + SF to get 28 days strength comparable to the control mix. A new method was proposed to find the efficiency factor of SF and FA individually in ternary blend cement system, based on principle of modified Bolomey's equation for predicting compressive strength of concrete using binary blend cement system. Efficiency factor for SF and FA were always higher in ternary blend cement system than their respective binary blend cement system. Split tensile strength of concrete using binary and ternary cement system were higher than OPC for a given compressive strength level.

• Journal of the Korean Society of Combustion
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• v.18 no.4
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• pp.12-20
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• 2013

The ignition delay time is an important factor to understand the combustion characteristics of internal combustion engine. In this study, ignition delay times of cool and thermal flame were observed separately in homogeneous charge compression ignition(HCCI) engine. This study presents numerical investigation of ignition delay time of n-heptane and alcohol(ethanol and n-butanol) binary fuel. The $O_2$ concentration in the mixture was set 9-10% to simulate high exhaust gas recirculation(EGR) rate condition. The numerical study on the ignition delay time was performed using CHEMKIN codes with various blending ratios and EGR rates. The results revealed that the ignition delay time increased with increasing the alcohol fraction in the mixture due to a decrease of oxidation of n-heptane at the low temperature. From the numerical analysis, ethanol needed more radical and higher temperature than n-butanol for oxidation. In addition, thermal ignition delay time is sharply increasing with decreasing $O_2$ fraction, but cool flame ignition delay time changes negligibly for both binary fuels. Also, in high temperature regime, the ignition delay time showed similar tendency with both blends regardless of blending ratio and EGR rate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.143-148
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• 2016

The aim of research is inducing the optimum proportion of fly ash(FA) and blast furnace slag(BS) for ternary cement. In this research, hence, the fundamental properties of mortar mixtures were evaluated depending on various proportion of FA and BS. The results of the experiment, within the scope of the study, obtained the following conclusions. Flow of the mixtures was increased with addition of binary supplementary cementitious material(SCM), and especially, portion of FA. The air content of the mixtures was increased with addition of binary SCMs, while it was decreased with increased FA content. In the case of unit mass, increased value was obtained due to the increased air content within 25 to 45% of binary SCM content, while it was increased within 65 to 100% of binary SCM up to only 20% of FA content and decreased more than 20% of FA because of the low density of FA. The setting time of the mixtures was delayed with addition of binary SCM and FA. In the case of compressive strength, at 91-day age, the highest value was obtained with 25 and 45% of binary SCM with the proportion of FA to BS of 40 to 60. Therefore, based on the compressive strength, it is considered that the binary SCM content of 25 and 45% with the proportion of FA to BS of 2 : 3 is the most favorable conditions in this research scope.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.125-126
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• 2021

Fly ash, has been widely used as one of the main supplementary cementitious materials (SCMs) in the world, to replace part of cement to significantly save energy and reduce greenhouse emission. Via mechanical activation, fly ash can replace more cement without impairing early age compressive strength. This study focuses on the strength-based evaluation of carbon dioxide emission for blended cement composite containing mechanically activated fly ash. Results indicate that under similar compressive strength, a prominent drop has been witnessed in embodied energy of binary cement and CO2 emission of the composite containing mechanically activated fly ash compared with those containing ordinary fly ash.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.421-424
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• 2008

The purpose of this experimental research is to investigate the influence of cement types on the resistance to acid and sulfate. For this purpose, concrete specimens with three types of cement such as ordinary portland cement(OPC), binary blended cement(BBC), and ternary blended cement(TBC) were made for water-binder(W/B) ratios of 32% and 43%, and then according to JSTM C 7401, the appearance change and ratio of mass change of them were estimated through the immersion tests by 5% sulfuric acid, 10% sodium sulfate, and 10% magnesium sulfate solution, respectively. It was observed from the test result that the resistance against acid and sulfate increased with decreasing W/B ratio and those of BBC and TBC concretes were better than the case of OPC concrete from immersion tests of 91 days.