• Proceedings of the Korean Institute of Building Construction Conference
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• v.y2004m10
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• pp.11-14
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• 2004

The object of this study is vibrating compaction and curing method in the production process of Design concrete for precast concrete(Design-PC) product. From change of vibrating compaction time and pre-curing time. curing temperature which would be factors of product quality in Design-PC concrete production. and research of optimized steam curing condition from relations between curing condition and strength development. basic data of vibrating compaction time and concrete steam curing method for Design-PC will be presented.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.449-456
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• 2014

Material properties of geopolymer, whose the reaction is very complicated, have been influenced by chemical compositions and particle size distributions of fly ash, concentrations and types of alkali-activators and curing conditions such as temperatures and time. In this research, experiments with several variables such as curing temperatures, preset prior to the high temperature curing and high temperatures have been conducted in order to evaluate to investigate effects on the compressive strengths of geopolymer caused by curing condition. Experiment results were evaluated with compressive strengths and micro-structures such as SEM and MIP of geopolymer pastes. As a result, as higher curing temperature or longer preset time were applied to the pastes, higher compressive strengths were observed. However, compressive strengths of geopolymer pastes declined due to increases in macropores (>50 nm) under high temperatures elapsed after 24 hours. In this sense, it can be considered that strengths and microstructures of geopolymers depends on curing temperature and time.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.17-24
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• 2008

Many problems exist in the current cast in place concrete lining used in domestic tunnel construction. Especially, the crack of tunnel lining brings about a social and economic problem. It has a lot of influence on stability of structure and the fine finish of lining. So enormous repair-work and reinforcement of tunnel lining could occur an running out of government's budget. In our country, there are domestic production enterprises which produce a special pre-cast concrete product, but the technical level of them is still far behind compared to developed countries. Also, optimum steam coring method is important for the production of high quality product. But there is no regulation of steam curing method in our country. This study is to investigate the properties of PC panel according to the variation of steam curing conditions such as presteaming time and rate of temperature rise. The result shows that the optimum presteaming time of steam curing method in PC panel is more than 1 hour and the desirable rate of temperature in curing chamber is about $20^{\circ}C/hr$.