• Journal of the Korea Institute of Building Construction
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• v.3 no.3
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• pp.73-81
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• 2003

In this paper, salt damage resistance of high durable concrete was tested. High durable concrete was made by using low water cement ratio, chemical admixture called super-durable admixture and mineral admixtures such as fly-ash, ground granulated blast-furnace slag, silica fume. Two kinds of salt damage resistance test were carried out. One method is chloride ion penetration test(ASTM C1202), and the other one is depth of chloride penetration test in saline solution. Test results were as followers: 1) The depth of chloride ion penetration increased exponentially as water cement ratio was increased and time passed. 2) Super-durable admixture had little effect on the improvement of salt damage resistance of concrete. 3) Silica fume and ground granulated blast-furnace slag were effective on salt damage resistance because of pozzolanic reaction, but fly-ash had a little effect.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.127-128
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• 2020

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent 20℃ conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.709-712
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• 2008

RC super tall buildings are planned and constructed recently in domestic area. Concrete is characterized by time dependant material such as creep and shrinkage. For this properties of concrete, differential shortening is one of the main issues on super tall buildings construction. This study includes material research, which is performing as a pre design stage to solve differential shortening on Lotte Super Tower Jamsil core structure(50, 60, & 70 MPa). The major part of this study is composed with comparison and analysis between experimental data and predicted data on total shrinkage and total compliance which were used on design stage. Four models, ACI209R Model, Ba${\check{z}}$ant-Baweja B3 Model, CEB MC99 Model, & GL2000 Model, were employed to predict them. It also tries to seek a proper model for high strength and high performance concrete in the case of no concrete test.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.142-145
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• 1998

The purpose of this study is to estimate lateral formwork pressure controlled by super-workable fresh concrete using prototype structrues such as, tall wall, retaining wall, and beam quantitativly. As a result of this experiment, a function which can be used to design a formwork system and to predict formwork pressure curve is formulated.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.753-756
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• 2006

This paper discussed pozzolanic reaction properties of classified fly ashes by using of electrostatic precipitator. Blaine values of fly ashes at hoppers are respectively about 3000(ordinary), 5000(fine) and 8000cm2/g(super-fine). The pozzolanic reactivity of fly ash at early stage and at later stage are respectively related to the related to the fineness and the glass content of fly ash. But the early hydration of cement was retarded by addition of super fine fly ashes. the adiabatic temperature rise of mortar containing fly ash is increased with the fineness of fly ashes.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.271-275
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• 1996

This study was performed to analyze flowing properties with kinds of the super-plasticizer and flowing effects with agitation method of the mixer truck. After that, this study presents the reference data about better flowing method and quality control when flowing concrete is applied in practice.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.469-470
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• 2009

Recently, so that HSC can secure the fire resistance properties at the time of a fire in super tall building suggested method of combined fiber. Thus, there is the purpose to develop the high fireproof concrete which applied method of combined fiber which can satisfy flowability and the fire resistance properties of HSC for construction of the super tall building.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.609-612
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• 2008

Ultra Super Early Strength Cement is a material that satisfies these requirements. early hydration heat however, is significant over regular concrete, thus discretion is advised for thermal cracks in accordance with heat generation when constructing a large-scale structures. In addition, the negative point that it is difficult to achieve required strength in a short period of time following rubbing process while retaining workability, the cement is being used conditionally for engineering material and Ultra Super Early Strength Cement for maintenance material for construction doesn't exist. Magnesia Phosphate Cement, which is currently under studies in overseas uses no extra admixture and has strong points of Ultra Super Early Strength as well as favorable construction-ability and adhesive stability to the prototype concrete. These factors stem recognition that it could be used as maintenance material for construction of diverse applicability. In order to provide necessary data to increase practicality of the magnesia phosphate cement for Ultra Super Early Strength Mortar, the study carried out simulate experiment on member of framework to review field applicability.

• Magazine of the Korea Concrete Institute
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• v.16 no.3 s.80
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• pp.34-41
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• 2004

• Magazine of the Korea Concrete Institute
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• v.26 no.2
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• pp.14-19
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• 2014