• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.427-430
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• 2005

The purpose of this study is to choose the right chemical admixture to reduce slump loss of lightweight aggregate concrete. So we compare 3 types of chemical admixture as measuring slump loss from mixing to 60 minutes. The lightweight aggregate of this study is made by clayt and dust from lots of industry. To save natures, we will use many types of industrial wastes and try to spend much making artificial aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.399-400
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• 2010

This paper presents results of an experimental program for evaluating the mechanical properties of green strain-hardening cementitious composite (SHCC) using recycled material. Recycled poly ethylene terephthalate (PET) fiber, fly ash, and recycled sand from waste concrete are used as materials for green SHCC. Test results indicated that average tensile strength of five dumbbell-shaped specimen is 4.76MPa and average compressive and flexural strength of three specimens are 38MPa and 7.40MPa, respectively.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.3-12
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• 2000

Recently, the amount of disposed construction materials like demolished concrete is growing fast and the shortage of natural concrete aggregates is becoming serious. Therefore, recycling of aggregates extracted from the demolished concrete is getting important and use of the recycled aggregates for concrete has been seriously considered. However, the use of the recycled aggregates even for low performance concretes is very limited because there are few rational standard evaluation criteria for recycled aggregates which should be different from that for natural aggregates. In this study, rational evaluation criteria for the recycled aggregates are proposed for their use as concrete aggregates. The study also shows that the performance for both the recycled aggregates and the recycled concrete manufactured with the recycled aggregates can be evaluated effectively according to water absorption ratio of recycled aggregates.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.377-382
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• 2010

건물의 대형화 고층화로 고강도 콘크리트의 사용이 증대되면서 고강도 콘크리트의 화재 시 폭열 대책이 필요하다. 본 연구는 전국 화력발전소에서 매립되는 Bottom Ash와 EPS를 재활용하여 건축소재의 내화기준에 만족하고 자원순환 소재의 새로운 개발방향을 제시하고자 난연성이 가미된 경량콘크리트 패널을 개발하여 그 난연 성능 및 벽체로서의 성능을 실험하였다. 실험은 Bottom Ash를 활용한 코팅 경량골재를 2개 Type으로 개발하여 단위중량, Flow, 압축강도, 열전도율, 부착강도, 건조수축, 흡수율, 난연 성능을 평가하였다. 그 결과 대부분의 데이터가 KS기준에 맞게 나왔으며, 난연 성능 또한 1급으로 나왔다. 이로서 폐자재인 Bottom Ash와 EPS를 재활용하여 화재 시 난연성능이 확보됨은 물론 국가성장핵심 사업인 녹색성장에 걸맞은 새로운 경량콘크리트 패널을 개발할 수 있게 되었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.21-24
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• 2005

A by-product of construction can be easily reused through properly treatment. On the contrary, the level of technique to reuse the by-product is not so high. Especially, the bulky of trash concrete is huge. The demand and treatment cost of them is on the increase. So, the riffle effect of the recycle of the trash concrete cannot be bypassed. But the research on the recycle of them is few. Therefore, the reuse of recycled concrete, the treatment of them, and the promotion plan of them were suggested in this study

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.3_4
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• pp.90-98
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• 1995

The recycled concrete, average compressive strength of which was 2l0kg/cm$^2$ or higher with slump range of 14~18cm, was prepared by replacing 25% and 50% by weight of coarse aggregate with recycled aggregate from waste concrete. Mix design method for crushed aggregates was used and all specimens were cured by normal moisture curing method. A plasticiser and a fly ash were added to the mix to improve performance of recycled concrete. Flexural strength, stress- strain relationship and fracture toughness were evaluated by comparing with those of normal concretes. Recycled concrete showed, in general, lower flexural strength and fracture toughness, and higher strain under the same stress level. Fly ash in the concrete had an effect of reducing the strength and fracture toughness on both normal and recycled concretes. Since fly ash is known to improve many properties of concrete, while reducing strength properties, decision for using fly ash should be made carefully depending on the intended usage of the recycled concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.78-79
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• 2013

A policy for recycling waste concrete has been extensively studied, but it is still lacking to recycle and reuse as a cementitious powder, and the property has big different depending on the aggregate rates. In this study, the amount of cement powder according to the internal properties of the aggregate were mixed. From as a result, Concrete Powder to play inside the aggregate composition of the cement composition CaO rigs that causes loss of power and strength reduction due to rising real water cement ratio will affect large.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.109-112
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• 2005

The electrical pulse separation of concrete samples for the recycling purpose has been investigated by the electrical disintegration method using the discharged high voltageimpulse. First, when the consumed energy increased in electrical crushing, fracture section area increased clearly. This result suggests that crushing energy was consumed efficiently. Secondly, when conventional crushing after electrical disintegration is compared with only conventional crushing, gravels are more stable after electrical crushing. Thus, electrical crushing makes it easy to recover gravels from wasted concrete. In the next year, more efficient recovery of gravel for wasted concrete by electrical disintegration will be investigated. Thus, actual wasted concrete crushing by electrical separation and combination of conventional crushing will be carried out.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.111-119
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• 2011

Recently, urban redevelopment programs and expansion of social infrastructure have caused massive amounts of construction waste in construction fields, and the mounds of it keep increasing every year. The disposal of construction waste is emerging as a national and social issue and the recycled powder generated by the treatment process of waste concrete is all being abolished or buried. Therefore, the purpose of this study is to utilize waste sludge generated by the wet-type treatment process of waste concrete as materials(binder, filler) for cement composite. This study evaluates physical and mechanical properties of mortar using recycled powder according to heating temperature, contents and applications. As a result of the chemical analysis, recycled powder is composed mainly of CaO and $SiO_2$, and that it is even lower in the content of CaO than OPC. The charateristics of mortar using recycled powder, according to drying and heating temperature, shows that as the heating temperature increases, flow decreases. Also, compressive strength and porosity of mortar using recycled powder was superior when heating temperature was $600^{\circ}C$. Thus, it is revealed that an effective development of recycled powder is possible since the binder by cement composite recovers a hydraulic property during heating at $600^{\circ}C$.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.329-334
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• 2005

The use of Polymer Concrete (PC) is growing very rapidly in many structural and construction applications such as box culverts, hazardous waste containers, trench lines, floor drains and the repair and overlay of damaged cement concrete surfaces in pavements, bridges, etc. However, PC has a defect economically because resin which be used for binder is expensive. Therefore the latest research is being progressed to replace existing resin with new resin which can reduce the high cost. Here, Polymer concrete using the recycled PET(polyethylene terephthalate) has some merits such as decrease of environmental destruction, decrease of environmental pollution and development of new construction materials. The variables of this study are amount of resin, curing condition and maximum size of coarse aggregate to find out mechanic properties of this. Stress-strain curve was obtained using MTS equipment by strain control. The results indicated that modulus of elasticity was increased gradually in an ascending branch of curve, as an increase of resin content. Compressive strength was the highest for resin content of $13\%$. And Compressive strength was increased as maximum size of coarse aggregate increases. The strain at maximum stress increases with an increase of resin content and size of coarse aggregate. For the descending branch of stress-strain curve the brittle fracture was decreased when it was cured at the room temperature compared to high temperature.