• Cement Symposium
• /
• no.9
• /
• pp.36-43
• /
• 1981

• Cement Symposium
• /
• no.23
• /
• pp.49-58
• /
• 1995

• Cement Symposium
• /
• no.12
• /
• pp.90-104
• /
• 1984

• Cement
• /
• s.31
• /
• pp.29-35
• /
• 1969

• Cement Symposium
• /
• no.10
• /
• pp.30-34
• /
• 1982

• Cement
• /
• s.32
• /
• pp.33-38
• /
• 1969

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.224-227
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• 2004

The cement can be influenced by the temperature. Especially, when it is cold weather, it causes some problems in such properties as mixing, placing and curing of concrete. According to the Concrete Standard Specification(2003), in case of the average daily outdoor temperature below $4^{\circ}C$, it recommends to use the cold weather concrete. In this research, the on-site quality characteristics of the cold weather concrete using high early strength portland cement(Type III cement) were studied. As a result, the cold weather concrete using high early strength portland cement can obtain its excellent properties and benefit the cost of construction.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.445-448
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• 2006

In order to control the temperature crack of massive dam concrete, the selection of appropriate materials like binder, aggregates etc., is essential. To select the optimal mix proportion, ordinary portland cement(Type I) plus 25% of fly ash and low heat portland cement(Type IV) are used as binder, and 80mm of coarse aggregates are used to reduce the amount of binder and compare the compressive strength, hydration temperature and crack index. The results of this study are as following. 1. The strength of Type IV cement is advantageous on the long-term age. 2. According to the temperature measured on mock-up$(1.5m{\times}1.5m{\times}1.5m)$, and realized the thermal analysis, the Type IV cement carried out advantageous to control the thermal crack.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.44-47
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• 2003

High flowing concrete has not spread whole in the normal concrete structure, because it requires special quality control technique. Recently owing to the lack of natural resources and reinforcement of environmental standard, the construction cost of cement is rapidly increased. Also ready mixed concrete industry has gone through various economical difficulty as the manufacture cost of concrete is increased. So, the purpose of this study is to evaluate the qualities of middle fluidity concrete using the fly-ash and portland blast-furnace slag cement in order to decrease the amount of cement and resolve the problem of the quality control of high flowing concrete and the manufacture cost. The results of this study show that it reduces the amount of addition of superplasticizer and develope properties of concrete to the use the fly-ash and portland blast-furnace slag cement.

• Journal of the Korean Ceramic Society
• /
• v.28 no.11
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• pp.917-925
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• 1991

For the present experiment five Portland cement mortars are in order: mortars with two different water/ cement ratios (W/C=0.45 and 0.50, each having no chemical additive), and those with an additive such as superplasticizer, air-entraining agent or water-repelling agent. We fix the W/C ratio of mortars having additive so that their pastes can yield the same workability as that of the cement mortar of W/C=0.50 with no additive. It is shown that the freeze-thaw resistivity depends heavily on the characteristic of wide pores. Despite a good deal of wide pores, the air-entrained specimen shows a good freeze-thaw resistivity due to appropriate air-pores. And also the specimen with water-repelling agent, which proves to cause the microstructure to become hydrophobic, make good resistance to freeze-thaw cycles in spite of its high wide-porosity. Our suggestion is that the freeze-thaw durability of Portland cement mortar/concrete can be more effectively enhanced by using air-entraining agent or water-repelling agent, and simutaneously by taking proper measures against foaming and/or the increased tendency of wide-pore building due to additive.