• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.101-104
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• 2005

It analyzed the supply status of fine aggregate and find the point of issue related alternative fine aggregate through researches and interviews. The conclusions of the study are as follows. 1. Ready mixed concrete manufacture used crushed fine aggregate (15.5$\%$) and recycled fine aggregate (1.5$\%$) for alternatives aggregate than 1.3$\%$ in 1991. It is not allowed to use a recycled fine aggregate in ready mixed concrete, but they used it. 2. All alternative aggregate are satisfied the Korean Standard, But they showed low properties of mortar compared to when it replaced with natural fine aggregate. So, it is needed to make another special Korean Standard to use alternative aggregate in normal concrete by mixing method to recover the workability and compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.328-329
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• 2018

The problem of imbalance between supply and demand of fine aggregates in the southeastern region due to the decrease in collection of EEZ(Exclusive Economic Zone) sea sand has been raised. In this paper, the possibility of securing alternative aggregate as a means to solve the problem of fine aggregate shortage in the southeast region was analyzed. As a result of the analysis, the alternative aggregate is easy to manufacture and its quality can be secured. And, it is suitable to use as an aggregate with less environmental burden. In addition, institutional improvement measures are needed for effective utilization and recycling of alternative aggregates.

• 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.

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.187-194
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• 2014

With environmental regulations continuously being strengthened internationally the need to control environmental pollution and environmental load is emerging in Korea. The purpose of this study is to seek methods or using waste cementitious powder as an alternative raw material for limestone through the optimization of raw material and to quantitatively analyze the resulting reduction of $CO_2$ emission in order to contribute to solving the issue of waste, which is the biggest issue in relation to construction and global warming. The results of the study, show that waste cementitious powder can be used as an alternative raw material for limestone at OPC level, but it was also found that mixing fine aggregate cementitious powder into waste cementitious powder significantly affected the substitution rate for limestone with waste cementitious powder and the reduction of greenhouse gas. In particular, when fine aggregate cementitious powder was used at a rate of 0~20%, the substitution rate for limestone and the reduction in the rate of greenhouse gas emission was significantly reduced. It is thought that a technique to efficiently separate and discharge the fine aggregate cementitious powder mixed in waste cementitious powder needs to be developed in the future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.3-4
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• 2015

Environmental load reduction and sustainable development one of the study's research into the available material is discharged, remove the coarse aggregate and fine aggregate from waste concrete and utilizing the remaining cement fine powder as an alternative raw material for limestone is the main raw material of cement developing playback cement that was the purpose. Physical over existing research and chemical quality was confirmed was evaluated for durability by promoting carbonation test, research studies on the durability evaluation insignificant. As honipyul within the aggregate differential lung fine powder increases carbonation resistance performance've found that increased sharply and, S0 showed fairly similar to the OPC. Therefore, the development within the technology research to separate fine aggregate discharge fully differential and waste fine powder is determined to be the development and use of the playback durability of the cement with the carbonation levels corresponding to the OPC if made.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.65-68
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• 2009

Recycled aggregate by the recycling construction waste has a lot of advantage such as the developing the alternative resource and protecting of environment. However, recycled aggregate is used as the low quality grade, because the technic to remove old mortar from aggregate is low level. To use the recycled aggregate as high quality grade, it is important to develop the technic to produce the high quality recycled aggregate. To manufacture the high quality recycled aggregate, old mortar attached on the aggregates should remove efficiently. Therefore, in this study, we suggested the optimum condition to remove old mortar effectively using sulfuric acid and low speed wet rotary mill for high quality recycled fine aggregate. The results shows that the recycled aggregate satisfy on the standards of KS F 2573 in density, absorption and solid volume when, adequate condition of sulfuric mole ratio and aggregate ratio are make.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.61-65
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• 2003

Bottom ash among the coal ash is not used because of its poor properties. But encouraging the use of bottom ash as a construction material is a sensible method of utilization as it avoids the problems and costs associated with disposal and provides an alternative aggregate source. This study was aimed at using bottom ash as an alternative fine aggregate source to provide a solution to disposal and insufficient fine aggregate for the production of concrete. So properties of domestic bottom ash were estimated due to the difference of each domestic bottom ash. And compressive strength and durability were estimated as basic data to use bottom ash in building industries. As a result of the experiment, the very porous surface and angular shape of the bottom ash particles necessitate a higher apparent water-cement ratio. And due to the higher water requirement, the compressive strength and durability of mortar is lower than those of the control samples. But when 25 percent of the total dry weight of the natural fine aggregate was replaced by bottom ash, the engineering characteristics were similar.

• Advances in concrete construction
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• v.10 no.3
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• pp.237-245
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• 2020

Past research efforts already established geopolymer as an environment-friendly alternative binder system for ordinary Portland cement (OPC) and recycled aggregate is also one of the promising alternative for natural aggregates. In this study, an effort was made to produce eco-friendly mortar mixes using geopolymer as binder and recycled fine aggregate (RFA) partially and study the resistance ability of these mortar mixes against the aggressive environments. To form the geopolymer binder, 70% fly ash, 30% ground granulated blast furnace slag (GGBS) and alkaline solution comprising of sodium silicate solution and 14M sodium hydroxide solution with a ratio of 1.5 were used. The ratio of alkaline liquid to binder (AL/B) was also considered as 0.4 and 0.6. In order to determine the resistance ability against aggressive environmental conditions, acid attack test, sulphate attack test and rapid chloride permeability test were conducted. Change in mass, change in compressive strength of the specimens after the immersion in acid/sulphate solution for a period of 28, 56, 90 and 120 days has been presented and discussed in this study. Results indicated that the incorporation of RFA leads to the reduction in compressive strength. Even though strength reduction was observed, eco-friendly mortar mixes containing geopolymer as binder and RFA as fine aggregate performed better when it was produced with AL/B ratio of 0.6.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.265-271
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• 2014

It is strongly needed to investigate the fine sand as an alternative fine aggregate of well-graded river sand because the fine sand which is being enormously distributed in the midstream and downstream of Nakdong-River in Korea has a poor grading but good quality as a fine aggregate for concrete. Thus, the purpose of this experimental research is to evaluate the durability of concrete using the fine sand to utilize it actively as a fine aggregate. For this purpose, the concrete specimens using different fine sand were made for the specified concrete strength of 35MPa, and then their durability such as the resistance to freezing and thawing and carbonation, and drying shrinkage were evaluated. It was observed from the test results that the resistance to freezing and thawing and carbonation of concrete using the fine sand was similar to that of concrete using reference sand, but the drying shrinkage of concrete using the fine sand with small fineness was comparatively lager than that of concrete using reference sand.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3511-3517
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• 2015

It is necessary to maximize the durability of Concrete for the underground structure because its maintenance and reinforcement are difficult. For cracks due to drying shrinkage of the concrete on the characteristics of the material, there is a need for an alternative in the deterioration phenomenon that occurs. In this study, fundamental properties including drying shrinkage of mortar and concrete were investigated to replace fine aggregate from cooling slag for reducing drying shrinkage of mortar and concrete. In the case of rapid cooling slag fine aggregate, it was effective to reduce and restrain initial shrinkage of mortar and concrete, and compressive strength was increased through the all specimen in proportion to its replacement ratio.