• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.111-116
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• 1991

In order to discuss the mechanical properties of carbon fiber reinforced polymer impregnated cement composties with silica powder, experimental studies on CFRC were carried out. The types of fiber used which are in CFRC are PAN-based carbon fiber and Pitch-based carbon fiber. To examine the effects of types, length, contents of carbon fibers and matrices, their properties of fresh and hardened CFRC were tested. According to the test results, compressive, tensile flexural strength of polymer impregnated CFRC were remarkably increased more than that of air cured and autoclaved CFRC. Also, polymer impregnated CFRC were considerably effective in improving thoughness, freezing-thaw resistance and loss of shrinkage compared with air cured and autoclaved CFRC.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.27-34
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• 2005

The purpose of this study is to improve the durability performance of polymer modified cement composites for repair of concrete under combined aging conditions. The experimental procedure was divided into three parts. First, the replacement level of mineral admixtures in polymer modified cement composites were determined in an experimental study based on a Box Behnken design. Second, the flow value, compressive strength and chloride permeability test of sixteen types of mixtures were conducted. Test results show that the polymer modified cement composites were effected on the improvement of the compressive strength and permeability performance. Third, the effects on the replacement level of silica fume mixture was evaluated by the compressive strength, chloride permeability, chemical resistance and repeated freezing and thawing cycles test. They demonstrated that the polymer modified cement composites using mixture of silica fume, fly ash, and blast furnace slag improved the durability performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.211-212
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• 2021

This study was conducted to derive quantitative air void volume calculation techniques in various complexes with porosity. Calculation of voids in a complex is an essential factor in improving mechanical properties, and quantitative measurement techniques are needed because the environment is not constant to apply the currently used ASTM criteria. Using the analysis technique obtained through 2D image analysis, it is believed that meaningful results can be derived through Micro CT analysis results and cross-check later.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.349-356
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• 2006

At present, the selecting system and analytic estimation criterion on repair materials and methods of the deteriorated RC structures have not yet been set up in domestic. Under these circumstances, deterioration such as shrinkage crack, corrosion of rebar has been often occurred after repair, and this finally results in too frequent repairs. In this study, three types of repair methods were experimentally investigated by the accelerating test in a combined deterioration chamber and long-term field exposure test. Three types of repair methods applied in this study belong to a group of polymer cement mortar, which is commonly used in repair works. According to the results of this study, durability of repair mortar layers and corrosion properties of recovered rebar could be investigated in short period by the accelerating test in a combined deterioration chamber, which can simulate the condition of repeated high-and-low temperature and repeated dry-and-wet environment, spraying chloride solution and emitting $CO_2$ gas. After 36 month long-term filed exposure test in the coastal area, harmful macro-cracks are observed in the polymer cement mortar layer of some repair methods. These crack are considered to result from drying shrinkage of polymer cement mortar. Also, after 36 month exposure, amount of corrosion area and weight loss of rebar are found to be different according to the types of repair methods.