• KCI Concrete Journal
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• v.14 no.1
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• pp.23-29
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• 2002

Recent construction activities have given rise to civil petitions associated with vibration-induced damages or nuisances. To mitigate unfavorable effects of construction activities, the measures to reduce or isolate from vibration need to be adopted. In this research, a vibration-mitigated concrete, which is one of the active measures for reducing vibration in concrete structures, was investigated. Concrete was mixed with vibration-reducing materials (i.e. latex, rubber power, plastic resin, and polystyrofoam) to reduce vibration and tested to evaluate dynamic material properties and structural characteristics. Normal and high strength concrete specimens with a certain level of damage were also tested for comparisons. In addition, recycling tires and plastic materials were added to produce a vibration-reducing concrete. A total of 32 concrete bars and eight concrete beams were tested to investigate the dynamic material properties and structural characteristics. Wave measurements on concrete bars showed that vibration-mitigated concrete has larger material damping ratio than normal or high strength concrete. Styrofoam turned out to be the most effective vibration-reducing mixture. Flexural vibration tests on eight flexural concrete beams also revealed that material damping ratio of the concrete beams is much smaller than structural damping ratio for all the cases.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.335-340
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• 2002

By the recently, Environmental pollution is serious by the highly economic growth and expansion of lively country basic industry. Especially, in case of industrial waste and life waste leaped into a pollution source. Also, research for processing of waste and recycling countermeasure is a pressing question on national dimension because it is prohibited an ocean disposal and reclamation. In this study, it looked for fracture characteristic value of recycling a coal ash to decrease environmental pollution by picky and exhaustion of natural resources and to reduce self-weight to prepare for a tall building and earthquake. So a coal ash examined to be possible to do as construction material. It achieved compressive strength test and three points bending test with initial notch depth rate and age for variables to show a basic research data. From the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. From the results of the compressive strength test, the elastic modulus was experimentally proposed. Also on the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. The results that the strength and fracture energy value are lower than concrete or mortar is described in this paper. Also, it shows that the deflection at fracture decreases as the age increases and the notch sensitivity decrease. However, it is judged to be available to construction material if research is continuously gone forward.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.58-65
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• 2001

To produce the substitute for farmland were mixed concrete waste and organic wastes. To estirnate the application of the mixture for farmland components in the solid and the leachate from the mixture were analyzed according to the ordinance of the Waste Society in Germany. Plants were cultivated in the mixture and its harvests were measured. The results showed that the mixture from waste may be used for the reclamation of landfill and landscaping according to circumstances, and the best mixture was from 85% of concrete waste, 10% of sewage sludge and 5% of paper mill sludge.

• Resources Recycling
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• v.18 no.4
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• pp.44-51
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• 2009

In order to verify the effect of Surface Coating Anode and Solar Battery anode system, accelerated tests in the presence or absence of some chloride content and cracks were carried out. The potential-decay, protection potential and corrosion current density of reinforcing steel in concrete specimen were measured to evaluate the effectiveness of the system. From the test results, the application of the system led to the satisfaction on NACE's criterion in all mixtures of concrete. Additionally it was found that protection potential and corrosion current density were satisfied due to the application of Surface Coating Anode and Solar Battery anode system.

• Resources Recycling
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• v.9 no.3
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• pp.37-45
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• 2000

This paper presents the experimental test results on moisture and freeze-thaw resistance of hot mix crumb rubber modified (CRM) asphalt concrete mixture. To compare the differences in mechanical properties of conventional and CRM asphalt concretes, various tests were conducted under different moisture conditions and freeze-thaw cycles. Marshall mix design was also performed to determine the optimum asphalt contents for the both asphalt concrete mixtures. Test results revealed that the moisture and freeze-thaw resistance of CRM asphalt mixture was superior to the conventional asphalt concrete. As a result, it is considered that the utilization of waste tires in asphalt pavements has the potential of minimizing the damage due to the moisture and freeze-thaw.

• Resources Recycling
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• v.17 no.1
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• pp.73-79
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• 2008

Along with the increased social infrastructures and reconstruction, the demand for aggregate, which is used in concrete, has rapidly increased. However, there are problems due to the exhaustion of natural aggregate resources, and strict restrictions. In this study, the possibility of using rapid chilled steel slag as a substitutive material of fine aggregate is determined from the property test and mechanical test for the concrete that is made with rapid chilled steel slag, which highly decreases the free CaO, the main problem of the steel slag.

• Resources Recycling
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• v.18 no.3
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• pp.36-41
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• 2009

The objectives of this study are focusing on the issue with efficiently recycling for EAF slag as construction material such as an aggregate of concrete. This study can be classified mainly into two categories: the first section is the carbonation treatment of Electric Arc Furnace(EAF)-slag for obtaining soundness as using aggregate of concrete. And the second section is the application of carbonated EAF-slag on the mortar test to evaluate the stability and mechanical property, which is compressive strength, according to the replacement of EAF-slag on the mortar. It was known that pH of EAF-Slagle according to carbonation time decreases drastically to 7 within several sec of carbonation, and a calcite is formed on the surface of EAF slag. The formation of calcite during the carbonation process of EAF slag lead to fill at pore in the texture of EAF-Slag surface, and than the porosity of EAF-slag decreases with carbonation process. In the mortar test, compressive strength, according to the replacement of EAF-Slag to sand on the mortar, the compressive strength of mortar increased as the 50% replacement ratio of EAF slag for sand was above 10% higher than that of reference mortar according to 50% replacement of EAF slag.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.20-27
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• 2019

Compared to the development and manufacturing technology of electronic goods, the development of waste glass recycling technology is relatively insufficient, leading to the acceleration of waste of resources and environmental pollution. Although waste glass recycling technology is being actively developed overseas, waste glass recycling technology is insufficient in Korea, leading to the illegal dumping or burial of waste glass. Waste glass has been confirmed to have pozzolan reaction potential when having hydration reaction with cement. Waste glass is also reported to be effective in reducing bleeding and inhibiting the development of hydration heat by improving the physical properties of concrete and the rheology properties of fresh concrete. Therefore, this paper analyzed the strength characteristics and the effect of alkalic-silica reaction on the expansion of shielding concrete that used waste glass as fine aggregate. Where, suitable admixture materials were used as a measure to suppress the expansion.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.111-116
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• 1998

Most previous wave tests for concrete have been done to evaluate static material properties, and thus there are less works to investigate dynamic material characteristics of concrete, which should be few in Korea. The objective of this experimental work is to investigate dynamic material characteristics of concrete, such as dynamic elastic modulus, dynamic shear modulus, first resonant frequency, dynamic poisson's ratio and etc. A dynamic Signal Analyzer has been used to perform the wave analysis for various dynamic material properties of test specimen. First Fourier transform technique has been carried out on various wave data acquired by the Resonant Column method, which is a kind of nondestructive tests. Wave analysis has been performed based on KS F2437, which is similar to ASTM C607-71 and is identical to JIS A 1127-1976.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.1-6
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• 1998

Recently, as to destruction and renovation of aged building, waste concretes have been reclaimed near foreshore and filled up underground. Recycling demolished concrete as aggregate helps to settle economic and environmental problems of obtaining superior aggregates from natural sources and to dispose waste concretes. An experimental study was carried out to investigate the strength characteristics of no-fine concrete containing recycled aggregates. The cement-aggregate weight ratios of 1: 5, 1: 6, 1: 7 and water-cement ratios of 30, 35, 40, 45% were chosen for the mix design of no-fine concretes. The compressive and splitting tensile strength at 7 and 28 days were measured for 12 different mixes. On the basis of test results, the optimum mix proportion of no-fine concrete containing recycled aggregates was determined and applied to the production of retaining wall block.