• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.116-119
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• 2003

The Natural aggregate will be faced with serious shortage problem within 10 years due to the great amount of consumption in domestic. In order to reserve our natural resources, the construction waste has to be reused as an alternative material. Especially, It is more imminent to find alternative material in case of fine aggregate. This paper presents and experimental results on the fundamental property of concrete using recycled fine aggregate. As a result, it was found that the property of concrete using recycled fine aggregate substituted for 25% of a natural sand was similar in that of crushed fine aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.513-516
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• 2005

Previous study on recycled aggregate(RA) has largely been limited to the manufacture of nonstructural-grade concrete due to undesirable physical properties of them such as, high water absorption leading to high water demand of concrete. The restriction seriously limits its market and consequently diminishes the use of RA as a construction material. This paper presents the mechanical properties of recycled concrete substituted by both waste foundry sand(WFS) and recycled coarse aggregate replaced with fine and coarse aggregate concurrently. The result shows that the compressive and tensile strength decrease with the increment of substitution ratio of RA and WFS while bending strength of RA concrete increase.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.46-47
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• 2015

This study has analyzed the engineering characteristics of resource-cycling mortar according to the variation of fine aggregate type using illite with high development potentials by setting the goal as developing eco-friendly construction materials. As a result, while flow has increased if recycled fine aggregate and waste refractory are used separately or mixing them adequately in case of flow and compressive strength, the flow had somewhat declined followed by illite replacement. However, the possibility of such usage is determined to be adequate if used by mixing illite, recycled fine aggregate and waste refractory properly due to the dry shrinkage effect.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.171-178
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• 1996

This study evaluated mechanical characteristics and performance of recycled concrete as a pavement material for use in low volume road. The recycled concrete was prepared by replacing a half of coarse aggregate with recycled coarse aggregate. Natural sand from a source was used as fine aggregate together with admixtures, such as plasticizer and fly ash (0.8% and 5% by wt. of total binder, respectively). From experimental evaluation. it was found that flexural strength. compressive strength, elastic modulus and fracture toughness of recycled concrete at 28 days were approximately $45kg/cm^2$, $250kg/cm^2$, $230,000kg/cm^2$ 및 $0.863 MPa{\cdot}m^{1/2}$. respectively. Long term strength and fracture toughness were improved significantly at the age of 6 months. In conclusion. mechanical properties of the recycled concrete were acceptable for use as concrete pavement materials in low-volume roads in rural and urban areas.

• Magazine of RCR
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• v.13 no.4
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• pp.48-53
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• 2018

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.93-100
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• 2006

Building materials are trending toward environmental materials nowadays and the market share of those is growing. So those researches and developments for environmental property are proceeding now. The main properties of environmental products are far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus, these products are used with shape of mortar, and spray on the finish material. But There are not much researches for the concrete, main material in construction field, with those functional properties. So in this research we evaluated slump, compressive strength and air content as basic properties for concrete using functional materials of sericite, wood pattern sand stone, carbon black and nanometric silver solution and functional properties like far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus. The results were as follows. The most useful material in the functional materials was carbon black. Sericite and nanometric silver solution had a little effect on functional property, so it was difficult to apply to concrete, and wood pattern sand stone had a high functional property but low compressive strength, can be applied to a factory product. Anti fungus of the concrete using nanometric silver solution was not clear but if those specimens were aged in $CO_2$ gas for a long time it might apparent.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.145-151
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• 2014

This paper evaluated the quality properties of Finex Water Granulated Slag fine aggregate as part of a study to recycle the Finex Water Granulated Slag generated in korea, and examined the availability as fine aggregate for concrete by comparing properties (properties of fresh concrete, mechanical properties of hardened concrete) of concrete using Finex Water Granulated Slag fine aggregate with properties of concrete using river sand as fine aggregate. From the results of this study, it was found that quality properties of concrete using finex water granulated slag as fine aggregate and concrete using river sand as fine aggregate are equivalent level.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.281-286
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• 2001

The development of automobile, vessel, rail road, and machine industry leads increase of foundry production used as their components, which cause a by-product, waste foundry sand (WFS). The amount of the WFS produced in Korea is over 900,000 ton a year, but most WFS buries itself and only 5~6% WFS is recycled as a material in construction materials. In this study, WFS is used as a fine aggregate for concrete. Five types of concretes aimed at the specified strength of 240$\pm$10 kgf/$cm^{2}$ , air contents of 4.5$\pm$1% and slump of 12$\pm$1.5cm were mixed with washed coarse seashore sand(WFS) in which salt was removed and then optimum mix proportion of concrete was determined. Moreover, basic properties such as setting time, workability, bleeding and slump loss of the fresh concrete with WFS were tested and compared with those of the concrete mixed without WFS. In .addition, both compressive strength of hardened concrete at each ages and tensile strength of it at the age of 28 days were measured and discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.667-670
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• 2003

The purpose of this study is to present data for the reusing, reinforcement and estimation of safety of the RC structure damaged by fire, and for the prevention of explosive spalling by checking the character of explosive spalling according to kinds of fine aggregate, admixture and water-cement ratios. The materials used fine aggregates were sea sand, crushed sand and recycled sand, and the admixtures were fly ash and blast-furnace slag. Also the water-cement ratios was 55% and 30.5%. After those were heated respectively for 30 and 60 minutes in accordance with Standard Time-Temperature Curve. And then conditions of explosive spalling were divided into five grades, and characters of explosive spalling were investigated.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.75-81
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• 2012

In case of crushing rock to produce materials for lean concrete subbase layer in concrete pavement, natural sand is used for the gradation adjustment of aggregates, and the percentage of natural sand used is 30%~40% of the weight ratio of aggregate mix. The supply of natural sand that is used in lean concrete as a fine aggregate is getting harder due to the current of exhaustion of source, and the cost for the purchase of natural sand is included in the cost of roadway construction. This study, therefore, was conducted in order to resolve the exhaustion of materials and economize in construction expenditure by the application of screenings, which is by-product of crushing rock in quarry, as an alternative to natural sand. As a result of a comparative analysis on the application of screenings and natural sand with typical types of rock that is produced in domestic, which was conducted in the first year, It is found out that the use of screenings as a fine aggregate showed better unconfined compression strength. Verification of actual application of screenings was conducted in the second year, after test construction and follow-up investigation. The compressive strength, compaction density, settlement of screenings applied case was higher than that of natural sand. Thus, it is expected that application of screenings to construction in field will contribute to the cost saving, material recycling and the protection of environment.