• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.77-78
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• 2011

This study is analysis of effect of binder types and replacement ratio on the properties of blast furnace slag mortar using the recycled fine aggregates. The results of the study were was follows. Compressive strength was increased according to an increase in replacement ratio of fine particle cement and gypsum. Absorption was reduced according to an increase in replacement ratio of fine particle cement and recycled aggregate fine powder.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.93-95
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• 2011

This study is to investigate experimentally the engineering characteristics of cement mortar incorporating both recycled aggregate powder (RP) below 0.08 mm and cement kiln dust(CKD). RP is substituted for fine aggregate ranged from 5~15% and CKD is also substituted for RP from 10~30%. The use of RP resulted in a decrease in flow value at fresh mortar, while an increase in CKD did not affect the flow value significantly. The combination of RP and CKD provided slight increase in compressive strength at early and 28 days and in the high curing temperature at early age showed an increasing Strength value.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.28-36
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• 2019

The adhered mortars in recycled aggregate may lower the performance of the concrete, such as by reducing in strength and durability, and cracking. In the present study, the effects of nylon fiber (NF) on the mechanical and durable properties of 100% ordinary portland cement (OPC) and 50% ground granulated blast furnace slag (GGBFS) concretes incorporating recycled coarse aggregate (RA) were experimentally investigated. Concrete was produced by adding 0 and $0.6kg/m^3$ of NF and then cured in water for the predetermined period. Measurements of compressive and split tensile strength, water permeable pore and total charge passed through concrete were carried out, and the corresponding test results were compared with those of concrete incorporating crushed coarse aggregate (CA). In addition, the microstructures of 28-day concretes were observed by using SEM technique. Test results revealed that the RA concrete showed lower performance than CA concrete because of the adhered mortars in RA. However, it was obvious that the addition of NF in RA concrete was much effective in enhancing the performance of the concretes due to the bridge effect from NF. In particular, the application of NF2 (19 mm) exhibited a somewhat beneficial effect compared with concrete incorporating NF1 with respect to mechanical properties, especially for RA concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.161-168
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• 2023

Converter slag is a by-product generated by refining the pig iron produced into molten steel in the blast furnace, occupying about 15 % of the weight of steel production. It has a high free-CaO content that can generate expansion cracks when used for concrete aggregate. This is the main reason to make it difficult to recycle. To solve this problem, government guideline requires that converter slag has to be aged in an open yard for 90 days. However, aging can not be perfectly performed because it entails time and cost. In this study, we tried to investigate the applicability of converter slag as a cementitious material rather than an aggregate by mixing converter slag with mortar formulations. According to the EDS results of the converter slag in the experiment, we found that screening in the aggregate phase was more effective than that in the powder phase. When the particles separated by a magnet in the aggregate state were pulverized and used for concrete up to a 15 % replacement ratio, various engineering characteristics, such as flow, length change, and compressive strength, showed engineering characteristics similar to those of the control mix.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.160-169
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• 2015

In this study, experimental research was carried out to improve the seismic performance of reinforced concrete exterior beam-column joint regions using replacing recycled coarse aggregate with hybrid fiber (steel fiber+PVA fiber) in existing reinforced concrete building. Therefore it was constructed and tested seven specimens retrofitting the beam-column joint regions using such retrofitting materials. Specimens, designed by retrofitting the beam-column joint regions of reinforced concrete building, were showed the stable failure mode and increase of load-carrying capacity due to the effect of crack control at the times of initial loading and bridge of retrofitting hybrid fiber during testing. Specimens BCJGPSR series, designed by the retrofitting of replacing recycled coarse aggregate with hybrid fiber in reinforecd beam-column joint regions were increased its maximum load carrying capacity by 1.01~1.04 times and its energy dissipation capacity by 1.06~1.29 times in comparison with standard specimen BCJS. Also, specimen $BCJGPSR_1$ were increased its energy dissipation capacity by 1.33~1.65 times in comparison with specimens BCJS, BCJP and BCJGPR series for a displacement ductility of 9.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.74-80
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• 2011

In this study, it is evaluated on the properties of mechanical performance, autogenous shrinkage and chloride resistance for application of high performance concrete for bridge deck overlay used slag powder and fly ash as a representative by-product of industrialization. According to test results, it is evaluated that the durability of concrete is improved the properties of chloride resistance, autogenous shrinkage and alkali aggregate reaction by using hydraulic mineral admixtures. It is considered to have a green construction and an economic feasibility on recycling of by-product as a improved concrete for durability and efficiency in materials and constructions.