• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.71-77
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• 2023

With the continuous industrial development, not only natural resource depletion, waste generation, but also various weather conditions are becoming more frequent. Efforts are continuing to recycle industrial by-products to overcome the climate crisis and save resources. Slag is a representative by-product generated in the steel industry, and it is characterized by improving rutting resistance and moisture sensitivity by increasing strength and reducing deformation when used as a material for asphalt concrete. On the other hand, slag has expansion properties so it is used as a relatively low-value-added material such as embankment and refilling materials. In order to expand the application of slag, an experiment was conducted to evaluate the crack resistance of slag asphalt concrete pavement. As a result of the indirect tensile strength test, it was found that the asphalt mixture using slag aggregate showed a value 1.13 times higher than that of the general HMA with the same particle size, and the toughness was 1.17 units, improving crack resistance. In addition, it was found that the failure number of the 4-point beam fatigue experiment and the slag asphalt mixture was 20,409, which was more than doubled compared to the general HMA. Furthermore, Overlay Test showed a tensile load residual rate of 4 times or more, improving crack resistance to repeated fatigue. Accordingly, the use of slag aggregate will likely have various advantages in improving the performance of asphalt concrete pavement.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.623-630
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• 2007

Grouting materials are used for the unification of superstructural and substructural body like bridge seat (shoe) or machinery pedestal and e.t.c by filling their intercalary voids. Accordingly, grouting materials have been developed and used mainly with products of high strength because those materials are constructed specially in a part receiving large or impact load. In this situation, the structural body constructed by grouting materials with high stiffness-centered (caused by high strength) products is apt to cause brittle failure when receiving over a limit stress and to cause cracks according to cumulative fatigue by continuous and cyclic load. In addition, grouting materials are apt to cause cracks by using too much rapid hardening agents that give rise to high heat of hydration to maintain high strength at early age. In this study, to overcome these problems, cement type grouting materials including powder of waste tire and resin as elastic materials which aim to be more stable construction and to be improvement of mother-body's unification are developed and endowed with properties of high toughness and high durability add to existing properties of high flowability, non-shrinkage and high strength. Besides, this study contribute to of for green construction materials for being possible recycling industrial waste like waste tire and flyash. On the whole, seven type mixing conditions are tested and investigated to choose the best mixing condition.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.99-106
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• 1999

Ultra-high molecular weight polyethylene (UHMWPE) was crosslinked in the melt state to enhance wear resistance, Dicumyl peroxide (DCP) and triallyl cyanurate (TAC) was used as a crosslinking agent and a promoter, respectively. With increasing amount of DCP and TAC used, gel content of crosslinked UHMWPE (XUMPE) increased, while the melting temperature, crystallizaiton temperature, crystallinity, and tensile properties decreased. The results of pin-on-disk wear test and ball-on-disk test with small applied load showed reduced wear volumes of XUMPE from that of the unmodified UHMWPE. As the wear mechanism effected in the experimental condition of this study was thought to be deformation rather than adhesion or fatigue, a new parameter, the ratio of maximum contact stress to yield stress, was proposed to correlate well with observed wear resistance. In ball-on-disk wear test with larger applied load, XUMPE showed higher wear volumes than that of the unmodified UHMWPE which were accompanied with increased friction coefficients and surface roughness of the wear tracks. When contact stress was well above yield stress, the failure of XUMPE, as well as deformation, was thought to be much accelerated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.155-162
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• 2012

When RC (Reinforced Concrete) structures are exposed to sea water, steel corrosion can occur and this leads a degradation of structural performance. Referring the electro-deposition system with sea water from the 1st step research, durability and structural performance are evaluated in coated steel and RC members containing it in the 2nd research. In the durability performance test, Half Cell Potential test is performed and the coated steel is evaluated to have the high resistance to corrosion, which shows only 35% of corrosion velocity in normal (bare) steel. In the structural performance test, tensile strength, adhesive strength, and flexural/shear in RC member are performed. For the electro-deposit coated steel, increasing ratios of 3.2% and 8.8% are evaluated in the test of tensile strength and adhesive strength, respectively. For the structural test in RC member, there is no big difference between RC members with coated and non-coated steel in ultimate load and failure pattern It is evaluated that the chemical compound with $CaCO_3$ and $Mg(OH)_2$ from electro-deposition causes slightly increased structural performance. The electro-deposit coated steel can be more widely applied after performance verification from several tests like fatigue, resistance to impact, and long term-submerging test.