• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.101-102
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• 2021

The compressive strength of concrete is greatly affected by the temperature inside the concrete at the initial age immediately after pouring. The apparent activation energy of cement and the setting time of concrete are major factors influencing the development of compressive strength of concrete. This study measured the apparent activation energy and setting time according to the change in W/B for each mixing rate of Ground Granulated Blast-Furnace Slag (GGBFS). And after calculating the compressive strength prediction model, the accuracy of the prediction model was evaluated by comparing the predicted compressive strength and the compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.165-166
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• 2022

In this paper, the characteristics of slag cement mortar added with neutralized liquid red mud with nitric acid to reduce pH by neutralizing liquid red mud with nitric acid were reviewed to improve strength degradation of cement concrete added with liquid red mud. As a result, the compressive strength of cement mortar added with liquid red mud was higher than that of Plain on 1 and 3 days, and the strength of red mud neutralized with nitric acid was lower than that of cement mortar added with liquid red mud on 7 days, but the strength was recovered on 28th. It was found that the addition of red mud has the effect of improving the strength in the early age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.305-306
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• 2023

Recently, as the radioactive waste disposal facility becomes scarce, the importance of efficient disposal of waste from nuclear power plants is increasing. This study was conducted to utilize radioactive waste concrete powder as solidifying agent for radioactive waste treatment. Paste with an age of more than one year was used with a disk mill to have a particle size of 150㎛ or less, and treated at temperatures of 500℃, 600℃ and 700℃ for 2 hours. In order to simulate the radioactive cement powder, aqueous solutions of Di-water, CsCl 1M, SrCl₂ 1M and CoCl₂ 1M were used as blending water at W/C 0.7 and to improve fluidity, polycarboxylate type superplasticizer was used at 0.4 wt.% based on the weight of recycled cement paste powder. Characterisation was carried out using vicat method, strength and density.

• Korean Journal of Human Ecology
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• v.20 no.3
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• pp.691-711
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• 2011

This study examines the preliminary license and approval facilitation standards for improvements in quality for childcare centers focusing on the number of children, building space standards, facilities and equipment, and childcare program. Data from 48 caese was collected from childcare centers nationwide in Korea through a questionnaire and building plan. The first step for starting care licensing is to work out the ages and numbers of children within four or five age ranges. The second step is to work out the number of children as small, medium, or large considering staff to child ratios and building size. The Nnext step is to make a choice about childcare service quality classification as minimum, fair, or good, considering space requirements per child for the building, the classroom and the outdoor playground. The next step is to make a choice of space organization relating to service programs, considering the sleeping and eating area, indoor play area, toilet & washing facilities, classroom layouts such as cluster type, double zone type, single zone type, and others. Also, each room and entrance, office, kitchen, storage, laundry, teacher's area, and chilldren's area, need to be checked for space requirements and performances. The last step is to arrange the childcare program with the building and site plan. In conclusion childcare service quality will get better by upgrading of license regulation especially in minimum space requirements per child, corresponding with an increase in GNP and housing area per person. This is needed for childcare licensing in order to determine the quality level of childcare service.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.61-64
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• 2002

The present age, it takes an interest in maintenance and preserve of the aged constructive materials cause destruction of environmental reason and a loss of resource. As answering question given to candidates at a civil examination, it is carbonated concrete construction materials to give alkalization agent to seek the plan to be extended durable life. The representative material, it was known for a chemical compound of alkailzation-Silica acid with Lithium and also used on inside and outside the country. But, it is so difficult to decide the effect because the work is to be repeated for a processing of construction. So, in this study, to investigate recovery faculty on a period of incubation that restrain processing of carbonation by impregnation alkalization agent, we were made good progress from basic test through comparative and analysis at laboratory and the spot of construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.45-48
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• 2005

This study is basic experiment for estimating influence of strength by curing temperature of concrete's heat of hydration and estimate relationship of compressive strength development by initial curing temperature factor, and then asume temperature factor which influence compressive strength development and for showing basic document of qualify control. According to the result of cement mortar by the curing temperature factor high-curing temperature shows high strength on 3 day compare with low curing-temperature, shows higher strength than the piece of high curing temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.212-213
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• 2018

The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.197-198
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• 2019

The aim of the research is evaluating the feasibility of inspection for early age frozen damage and for expansion of concrete under the various time periods of -20℃ temperature condition. When the concrete samples were exposed for 12 hours and 24 hours, the frozen depth of the concrete were 10 and 60 mm, respectively, under the wet conditions. From the experiment results of temperature and expansion, only surface area suffered frozen damage for 12 hours exposing conditions while entire area suffered frozen damage for 24 hours exposing conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.117-120
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• 2009

It has been gradually increased with the use of resin based membrane forming agent for curing method, which plays a role in protecting moisture evaporation by forming resin membrane at the surface of concrete. In this paper, tests were carried out to examine moisture retention capability of cement mortar applying membrane forming agent. Dosages and types of the membrane forming agent were varied. It is found that sheet curing sealed with the surface of concrete closely has favorable moisture retention capability. However, the application of membrane forming curing method had superiority in moisture retention capability at early stage but at later age, its capability is deteriorated. Hence, further study regarding altering application method was necessary to secure enhanced moisture retention capability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.297-298
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• 2021

The construction industry is a representative high levels of hazardous work environment, and the number of disasters in the construction industry is the highest compared to other industries. Information & Communication Technology(ICT) convergence technologies are being introduced worldwide, and this study considers ICT-based safety management cases at domestic and foreign, resulting in a list of technologies to recognize and resolve to construction site hazards. Technologies such as 「Development of hazard map considering cause, age, proficiency, type and timing of accident in construction industry」, 「Development of hazard map-based accident prediction platform using AI」, 「Development of smart safety management plan for whole construction work cycle」, 「Development of intelligent safety devices and smart safety equipment for mitigating hazard factors」 were derived as smart construction technologies that could solve this problem.