• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.151-156
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• 2002

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. LMC and RSLMC were studied for field applications very actively in terms of strength and durability in Korea. However, there were no considerations in drying shrinkage. Therefore, the purpose of this study was to investigate the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a controlled environment of 60% of relative humidity and 2$0^{\circ}C$ of temperature. The drying shrinkage for specimens was measured with a digital dial gauge of Demec. The test results showed that the drying shrinkage of LMC and RSLMC were considerably lower than that of OPC and RSC, respectively. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.799-804
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• 2003

The purpose of this study was to investigate the effects of re-vibration and curing temperature onto the physical properties of latex-modified concrete with ordinary cement and rapid-setting cement, and thus to provide a guide line of re-vibration and curing conditions for good quality controls. The main experimental variables included two cement types(ordinary portland cement, rapid-setting cement), curing Temperature($10^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$), re-vibration methods(continued, intermittent), and re-vibration times(initial setting, one day after mixing). The experimental results showed that the re-vibration affected little to the mechanical properties of LMC and RSLMC, while, the curing temperature a quite some. The early strength development was the highest at $20^{\circ}C$ curing temperature, and decreased at higher temperature. The permeability of concrete generally decreased with curing time. The rapid chloride permeability was a function of time and temperature. The chloride permeability of RSLMC was so small and negligible.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.87-88
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• 2018

In this study, the tensile properties of single and hybrid fiber reinforced cement composite according to strain rate was evaluated. Experimental results, in the strain rate 10^-6/s, fiber reinforced cement composite showed improved of tensile strength and decrease of strain at peak stress as SSF volume content increased. In the strain rate 101/s, the single and hybrid reinforced cement composite's tensile properties are improved, because of the improved bond strength between the fiber and matrix. And hybrid fiber reinforced cement composite showed high energy absorption capacity, because the SSF prevented the cracking and fracture of the surrounding matrix when during the HSF pull-out.

• Cement Symposium
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• no.22
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• pp.116-122
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• 1994

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.69-72
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• 1999

In this study, we blended 2 grades of ultra fine cement using the results of previous stud. And the cement slurry was produced by water each water/cement ratio. The slurries were observed hydration phenomena during 28 days with SEM, XRD and DSC. The specimen made by slurry were evaluated with the hardened properties such as compressive strength, flexural strength length change and water absorption. And were tested the adhesive strength of specimen made by injecting the slurry between mortar bars.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.35-39
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• 1999

For many years, alkali activated blast furnace slag cement containing no ordinary portland cement has received much attention in the view of energy saving and its many excellent properties. We examined the structural change of slag glass which was activated by alkali metal compounds using IR spectroscopy. The properties of hydrated products and unhydrated slag grains was characterized by XRD and micro-conduction calorimeter. Ion concentration change in the liquid during the hydration of blast furnace slag was also studied to investigated the hydration mechanism.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.93-94
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• 2023

This study evaluated the mechanical properties and microstructure of calcium silicate cement based paste according to carbonation curing conditions. As a result, both compressive strength and carbonation depth increased with the carbonation curing period.

• Journal of the Korean Ceramic Society
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• v.24 no.3
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• pp.289-295
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• 1987

The changes of physical properties of portland cement pastes and mortars were investigated by addition of sodium gluconate. Flow table experiment and viscosity measurement were took in order to find dispersing effect, and time-dependent changesof viscosity and rates of hydration heat evolution were carried out for the sake of finding retardation effect of hydration. And changes of physical properties of cement pastes and mortars were discussed by setting time, compressive strength and porosity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.290-295
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• 2000

Mechanical and physical properties of wood fiber for the reinforcement of thin-sheet cement products were investigated. The slurry-dewatering method followed by pressing was used to manufacture the products. Mechanical and physical properties of wood fiber reinforced cement composites were assessed with flexural strength, density, and water absorption. The results obtained in this study were analyzed statistically using the analysis of variance in order to derive statistically reliable conclusions.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.1-4
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• 1991

Relationship between againg and characteristic change of asphalt is not well known through asphalt rheolopy. Therefore, this study was conducted to evaluate characteristic change of asphalt cement due to againg based on experimental results of chromatogram and selected physical properties. Currently, three virgin asphalt cements were tested for physical properties and chromatograms before and after artificially conditioning for againg. Results in the current study showed that againg caused significant changes of physical properties and increase of larger size molecules and approximately corresponding reduction of smaller size molecule in asphalt cement molecular size distribution.