• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.557-560
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• 2003

This study deals with the method of test for waterproof agent and admixture of cement, and especially, the effect on bond strength between waterproofing layer and mortar or concrete substrate in building construction. Quality of that has been managed according to it of construction standard manual, housing construction manual, 건, and Q until performance of that is specified by law as KS F 4923. Therefore this study focus on the quality and trend for a fatty system and PCM(Polymer Cement Mortar)

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.509-512
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• 2003

Dehydration and micro crack thermal expansion occur in cement hydrates of concrete structure heated by fire for a long time. The characteristic of concrete exposed to high temperature can be analyzed from distribution of porosity and pore size. Porosity showed a tendency to increase irrespective of specimen types. This is due to both the outbreak of collapse of gel comprising the cement and a micro crack by heating. Porosity did not affect the variety of specimen and increased with the same tendency throughout every specimen. In addition, the deteriorate of compressive strength resulted from increase in porosity

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.125-130
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• 1997

This study is to investigate properties of relationship between the heat of hydration of several type cements and the temperature of concrete in restraint condition. As the results, the heat of hydration is largely affected by the temperature of cementious materials. However, the heat of hydration of cement and temperature rise of concrete is differently resulted in the content of cement.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.183-188
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• 1996

The durability of concrete structures decrease due to deterioration of concrete when they are constructed in marine or pollutional environments. In this study, the mortar specimens made from the five different types of cement were immersed in artificial seawater and four kinds chemical solution, and were measured the change of compressive strength and weight. The results show that the longer the immersed days are, the more the compressive strength reduction is. It has been remarked that the resistance of slag cement and ground granulated blast-furnace slag is excellent in chemical attack.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.76-82
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• 2002

The rapid-set cement concrete causes high hydration temperature and nay result in a high drying shrinkage and shrinkage-induced cracking. This problem may be fixed by incorporating polypropylene fibers in rapid-set cement concrete, because of increased toughness, resistance to impact, corrosion, fatigue, and durability. A series of concrete drving shrinkage tests was peformed in order to investigate the shrinkage properties of polypropylene fiber reinforced concrete with experimental variables such as concrete types, fiber reinforcement, W/C ratio, with and without restraint. Uni-axially restrained bar specimens were used for the restrained shrinkage tests. The results were as follows; The dry shrinkage of rapid-set cement concrete was much lessor than that oi OPC, probably because of smaller weight reduction rate by early hydration and strength development. The constraint and bridging effects caused by polypropylene fibers were great for the rapid-setting cement concrete when compared with that of plain concrete, and this resulted In increased resistance against tensile stress and cracking.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.124-129
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• 1995

In this study proposed to rapid and simple methid of test for early evaluation of strength of cement. The obtained results through a series of experiment are summarized as follow. The resistance ratio was decreased as the increase of water-cement ratio. The compressive strength of cement was increased as the resistance ratio increase. The experimental results of compressive strength of cement is shown in the same value no relation with the kind of cement respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.355-360
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• 2003

Recently, a cement plays an important roll in the materials field. So, in this research we would like to study on the properties of waste gas reduction in the photocatalytic cement. The fundamental phenomena of waste gas reduction in the photocatalytic cement were observed by the NOx analyzer with reaction chamber, UV Lamp, MFC, and humidity control bath. As a result of this study, the photocatalytic cement used photocatalytic powder, admixture and other materials can obtain NOx gas reduction and its photocatalytic efficiency. Developing for the photocatalytic cement, we need a various study.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.131-134
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• 1990

Many papers have been published on drying shrinkage of hardened cement paste and cement mortar. The causes of drying shrinkage in cement mortar may be attributed to its mechanical properties, temperature, curing time and the evaporation of water from cement mortar. This paper deals only with drying shrinkage in cement mortar. In particular, the relationships between water evaporation and drying shrinkage are discussed.

• KCI Concrete Journal
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• v.12 no.1
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• pp.79-89
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• 2000

This research developed an accelerated curing processe for cellulose fiber reinforced cement composites using vigorous reaction between carbon dioxide and cement paste. A wet-processed cellulose fiber reinforced cement system was considered. Carbonation curing was used to complement conventional accelerated curing. The parametric study followed by optimization investigation indicated that the carbonation curing can enhance the productivity and energy efficiency of manufacturing cellulose fiber reinforced cement composites. This also adds environmental benefits to the technical and economical advantages of the technology.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.407-410
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• 1999

The 5 types of cement mortar was immersed in the various chemical solutions for 400 days and then the compressive strength and the length change were measured to consider the chemical resistance at required ages. Due to the effect of flyashe and GGBF slag, the compressive strength of blended cement mortar was higher than that of portland cement mortar at long ages. According to the result of length change, the mineral admixture in blended cement had an indluence on reducing the amount of C3A, the cause of making concrete expand, and it made the formation of cements mortar denser so that the length change was much smaller than that of the portland cement mortar. However, the OPC mortar immersed in Na2SO4 solution for 180 days shows 4 times bigger length change chante than the blended cement mortar.