• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.293-298
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• 1997

Corrosion of steel reinforcing in concrete deteriorated by freezing/thawing and carbonation was characterized. Concrete specimens were prepared using various kinds of cements such as ordinary portland cement (type I), low heat portland cement (type IV, belite rich cement), sulphate resistance portland cement (type V), blast furnace slag portland cement and ternary blended cement. Of various cements, type V and type IV with lower $C_3A$ content revealed better steel corrosion resistance after freezing/thawing and carbonation. $C_3A$ content in cement might affect freezing/thawing resistance in sea water.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.141-151
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• 2000

Compressive strength, sulfate deterioration factor(SDF) and length change of 5 types of mortars immersed in sodium sulfate solution were observed. As the results of tests, it was found that the sulfate resistance of blended cement mortars were superior to that of portland cement mortars. Pore volume with diameter larger than 0.1 $\mu\textrm{m}$ of 5 types of pastes indicated that the micro-structures of blended cement pastes were denser, due to pozzolan reaction and latent hydraulic properties, than those of portland cement pastes. The XRD, ESEM, EDS and TG analyses demonstrated that the reactants such as ettringite and gypsum were significantly formed in portland cement pastes. Besides, compared with the $Ca(OH)_2$ content of ordinary portland cement pastes immersed in water and sodium sulfate solution, the $Ca(OH)_2$ contents of fly ash blended cement and ground granulated blast-furnace slag cement paste were about 58% and 28% in water, and 55% and 20% in sodium sulfate solution, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.271-273
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• 2012

This paper is to investigate the effect of waste cooking oil(WCO) on carbonation resistance of high volume fly ash and blast furnace slag concrete. WCO and paint were applied for carbonation resistance materials. As expected, the application of WCO to the concrete help it reduce carbonation depth remarkably, regardless of mixture types. This may be due to the fact that WCO makes the capillary pore block by activating saponification. It is found that the degree of carbonation reduce due to WCO is much higher than the case by Paint.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.147-150
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• 2008

Previously, we reported on the antibiotic resistance patterns of 50 strains of Staphylococcus aureus which were isolated from a hospital in Busan, Korea from July 2005 to December 2006. We have isolated small plasmids and classified plasmid types by agarose gel electrophoresis. We have selected 5 plasmids and determined complete nucleotide sequences of those plasmids. The aim of this paper is to report on the characteristics of cadmium, erythromycin, lincomycin resistance plasmids and a cryptic plasmid based on the sequence analysis obtained by using the BLAST program.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.139-140
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• 2019

In this study, we considered the influence on segregation resistance at the time of substitution of FA and BS, which are substance admixtures of high fluidity concrete. According to the research results, EIS, which is an index of segregation in high fluidity concrete replacement, showed a low value, and the composition also showed a higher value than OPC. Therefore, it is confirmed that the resistance to segregation at the time of admixture replacement of high fluidity concrete is improved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.44-45
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• 2015

Although the carbonation problem of high-volume slag concrete has been solved by the mixed use of emulsified refine cooling oil as the pilot study, there was an instance of securing air quantity and frost resistance followed by the use of Expancel due to the problem of having vulnerability in frost resistance in result as the air quantity has not been secured. But due to the problem of Expancel not being economical, air quantity and frost resistance of high-volume slag concrete mixed with ERCO are attempted to be secured using micro bubble that can remain in the water for a long time as a relatively economical and very microscopic bubble.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.30-31
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• 2017

The objective of this study is to evaluate the performance of polymer-modified surface preparation mortars with pozzolanic materials for corrosion prevention method in deteriorated sewage treatment structures. The prepackaged-type surface preparation mortars are prepared with a polymer-binder ratio of 10%, ground granulated blast furnace slag contents of 0, 15, 30%, a fly ash content of 15%. And, the specimens are tested for workability, adhesion in tension, water absorption, crack and impact resistance. As a result, the prepackage-type surface preparation mortars for sewage treatment structure are satisfied with quality requirements by KS F 4716, Japan sewage work agency(JS) and JIS A 6916 for surface preparation mortars.

• Journal of the Korea Institute of Building Construction
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• v.16 no.1
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• pp.17-24
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• 2016

Recently, exposed concrete by machinery trowel is generally used in industrial floor such as warehouse. Also, concrete using only the cement has been mainly used except mineral admixture in order to secure surface abrasion resistance. However, in hot weather construction, it is causing a serious problem such as workability inhibition of trowel using only ordinary portland cement. Due to this, it was investigated the effect of application of fly-ash and ground granulated blast furnace slag on properties and abrasion resistance of concrete for industrial floor in this study. The result of this study, it was confirmed that fly-ash and ground granulated blast furnace slag can be used in concrete for industrial floor without affecting significantly the properties of concrete.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.12
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• pp.165-172
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• 2019

The aim of the research is to evaluate the influence of various replacing ratios of supplementary cementitious materials(SCMs) such as fly ash(FA), blast furnace slag(BS), and both FA and BS on general properties including segregation resistance as a powder based high fluidity concrete of normal strength grade with water-to-cement ratio 0.40. Specifically, by replacing the SCMs with low density powders, it was assessed that the decreased segregation resistance due to the decreased viscosity by J-ring test. As a result of the experiment, from the general test, the mixtures with SCMs showed increased segregation resistance by increased viscosity as the references, while some segregation was shown from J-ring test due to the decreased density of fresh state mixture related with the capacity of delivering coarse aggregate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.557-564
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• 2009

In recent years, there have been numerous explosion-related accidents due to military and terrorist activities. Such incidents caused not only damages to structures but also human casualties, especially in urban areas. To protect structures and save human lives against explosion accidents, better understanding of the explosion effect on structures is needed. In an explosion, the blast overpressure is applied to concrete structures as an impulsive load of extremely short duration with very high pressure and heat. Generally, concrete is known to have a relatively high blast resistance compared to other construction materials. However, information and test results related to the blast experiment of internal and external have been limited due to military and national security reasons. Therefore, in this paper, to evaluate blast effect on reinforced have concrete structure and its protective performance, blast tests are carried out with $1.0m{\times}1.0m{\times}150mm$ reinforce concrete slab structure at the Agency for Defence Development. The standoff blast distance is 1.5 m and the preliminary tests consists with TNT 9 lbs and TNT 35 lbs and the main tests used ANFO 35 lbs. It is the first ever blast experiment for nonmilitary purposes domestically. In this paper, based on the basic experiment procedure and measurement details for acquiring structural behavior data, the blast experimental measurement system and procedure are established details. The procedure of blast experiments are based on the established measurement system which consists of sensor, signal conditioner, DAQ system, software. It can be used as basic research references for related research areas, which include protective design and effective behavior measurements of structure under blast loading.