• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.769-772
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• 2008

The problem of disposing construction waste materials has become a national and social problem. Recycled powder generated in the process of making aggregate, and the recycled powder is land-filled in its entirety. Results of toxicity testing of recycled power show that it contains base-pair substituent mutagenicity. As recycled powder is disposed of as landfill, it can cause secondary contamination such as soil and underground water contamination. There has been very little research made on recycled powder. This study has examined the utilization of concrete mixture by using recycled powder in a mixture instead of cement and compared and analyzed the characteristics of dynamics and workability. This study has examined the application of recycled powder in concrete. Depending on the replacement rate and workability, test piece was manufactured using different mixing rate by CP, WCP, PCP. The CP was used to examine the physical property of concrete and characteristics its dynamics. The letters W of WCP and P of PCP are the initials of water and mixture. They were made using the standard mixing ratiosemphasizing the workability to determine the characteristic of dynamics of concrete based on the mixing ratio of recycled powder. With the increase in the replacement rate, CP had very little change in the strength. But with the decline of slump, the workability was not good. The result of manufacturing WCP and PCP using the standard mixing ratio showed that WCP had a drop in strength compared to the plain. PCP had almost the same value as the plain only when the replacement rate was 10%. When it was higher than that, a reduction in strength was observed.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.52-60
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• 1998

• Magazine of the Korea Concrete Institute
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• v.15 no.2
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• pp.46-51
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• 2003

• Magazine of the Korea Concrete Institute
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• v.15 no.2
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• pp.52-59
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• 2003

• Magazine of the Korea Concrete Institute
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• v.15 no.2
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• pp.68-75
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• 2003

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.11-17
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• 1997

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.145-150
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• 2005

An extensive numerical analysis is carried out to investigate the slope stability of the wasted mine tailing landfill constructed by the utilization of fine recycled-concrete aggregates. To do this, first, the physical and mechanical properties of the fine recycled-concrete aggregates and the wasted mine tailing are investigated, and the settlement and the change of material properly of the fine recycled-concrete aggregates resulted from reaction with water are also examined. The $OH^-$ elution from the fine recycled-concrete aggregates reacted with water slightly causes the change of material properties such as porosity, permeability and waster absorption, but the settlement does not happen noticeably. The results of numerical analysis of the landfill slope built with wasted mine tailing and recycled-concrete aggregates in alternate layer indicate that slope stability increases with decreasing the slope ratio, with decreasing the groundwater level inside slope, and with increasing the depth of fine recycled-concrete aggregate layer. Based on this study, thus, engineers working in related to the wasted mine tailing landfill design and construction using the fine recycled-concrete aggregates should be considered the slope ratio, the groundwater level, the depth of fine recycled-concrete aggregate layer.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.21-29
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• 2005

One way to recycle the construction wastes is to use the waste concrete aggregates as the pavement materials. Although there are many studies and technical developments about waste concrete aggregates, the impurities produced in the process of the aggregate production prevent the use of the waste concrete aggregates in the pavement construction. In this study, the impurities included in the recycled waste aggregates were classified into inorganic and organic ones according to their characteristics, and the influences of each impurities on the pavement performance were presented. It was also showed that the limit of impurity content in the lean concrete base through the correlation between the inorganic impurity content and the compressive strength, and that in the granuler subbase layer through the correlation between the organic impurity content and the modified CBR. In conclusion, it is possible to apply waste concrete aggregates for the pavement when inorganic impurity content is less than 10% in the lean concrete base, and organic impurity content is less than 2% in granular subbase.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.133-136
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• 2006

This study tested gravity separation with heavy-medium to produce structural recycled aggregates. A result that could produce recycled aggregates attached mortar hardly.

• Resources Recycling
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• v.10 no.1
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• pp.7-15
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• 2001

We can reuse the portion of simple reclamation and the construction by-products. Until now, we have discarded concrete by simply throwing away or dumping in underground. Therefore, we attempted to propose the technical directions for the reuse of waste concrete as the recycled concrete aggregates and concrete structural materials. As a testing result, It is reasonable that standards are substitution of recycled aggregates under 30%, maximum steel ratio, under 70% of balanced steel ratio, under shear span ratio 0.2 for deep beam criteria for safety and Zsutty's equation is reasonable for estimation of factored shear strength