• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.69-72
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• 2011

The purpose of this study is to identify basic property of porous concrete using cooper slag as fine aggregate. The specimens were made with cooper slag with various mixing ratio(10, 20, 30, 50%), porous concrete and porous concrete containing river fine aggregate and crushed fine aggregate, which W/B ratio fixed 0.25. Compressive strength, Flexural strength, coefficient of permeability. From the test results, various fine aggregate mixing ratio improves compressive strength and flexural strength, but cooper slag fine aggregate mixing ratio over 20%, concrete indicates trend to decrease performance of permeability. Concrete containing fine aggregate is improved the performance of permeability and strength compared to other specimen, when age 28days, and cooper slag mixing ratio less than 20% concrete indicates better performance than cooper slag mixing ratio 20% over.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.126-127
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• 2020

Recently, as interest in environmental issues increases, minimizing carbon dioxide generated during cement manufacturing is a problem to be solved. In order to solve such a problem, it is required to use an industrial by-product of recycled aggregate, blast furnace slag, and circulating fluidized bed boiler fly ash to replace it on the basis of geopolymer(=cementless). This study examines the characteristics of eco-friendly artificial stone according to the mixing ratio of geopolymer-based recycled aggregate. As a result of the experiment, when the addition rate of the alkali stimulant was 15% and the mixing ratio of the circulating aggregate was 70%, the flexural strength and compressive strength were the highest. Density and water absorption decreased as density of circulating aggregates increased and water absorption increased. However, when the mixing ratio of the circulating aggregate exceeded 70%, the flexural strength and compressive strength decreased. Therefore, in order to obtain strengths meeting the KS standards, the mixing ratio of recycled aggregate was set to 70%, and artificial stone was manufactured using industrial by-products.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.367-375
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• 2022

In this study, the characteristics of recycled aggregate concrete according to the mixing ratio of recycled fine aggregate were analyzed by design strength to explore its use in the production of ready-mixed concrete. The results show that, depending on the ratio of recycled aggregate, the compressive strength is similar to that of normal concrete and does not deteriorate. Therefore, it is possible to achieve a strength similar to the target design strength. Furthermore, if the ratio of recycled fine aggregate for concrete is up to 25 % of the total aggregate amount (50 % of the to-tal fine aggregate), slump does not cause problems. Our findings show that the higher the de-sign standard strength, the greater the amount of powder, and management of slump reduction, unit quantity, and performance system is necessary. The obtained results show that recycled ag-gregate can be used for the production of ready-mixed concrete after adjusting its mixing ratio and concrete mix proportions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.4
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• pp.186-193
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• 1998

The purpose of this research is to seek properties of flowing light-weight aggregate concrete and possibility of application. The experimental analysis results by using light-weight aggregate and industrial waste such flyash, furnace slag are as follow. 1) The research shows that flowing light-weight aggregate concrete of slump 23~27cm, slump flow 58~69 cm is possible, but material segregation is appeared above slump 26.5cm and slump flow 65 cm. 2) If mixing ratio of flyash is increase, strength deterioration is about 25 % in early age. It showed that effectiveness of long time strength improvement because strength manifestation ratio is above 95% in a long term. 3) This research showed possibility of substitution of blast furnace slag because strength deterioration by using mixing of furnace slag was appeared small deterioration range as below 10 %. 4) Each experimental compressive strength ratios were 77 %(1st week), 86 %(2nd week), 109 %(8th week), 115 %(13th week), 125 % (26th week) on the basis of 28 days. If mixing ratio of flyash is increase, long term strength increase ratio is improved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.195-196
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• 2020

This study evaluated the mechanical properties and alkali silica reaction of mortar according to the mixing ratio of waste glass. As a result, as the mixing ratio of the waste glass increased, the compressive and flexible strength of the mortar decreased due to the slip of aggregate, and the alkali-silica reaction(ASR) increased. So, it is considered that research is needed to prevent slip and ASR of the waste glass aggregate in order to use the waste glass as a fine aggregate for concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.61-64
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• 2009

This study is reviewed fire resistance characteristics of high strength concrete according to changes in PP fiber mixing ratio and type of fine aggregate, and the results can be summarized as follows. As fire resistance characteristics, all plain crushed sands prevented spalling regardless of increase in mixing ratio of PP fiber. Mixtures other than the plain showed satisfactory spalling prevention when 0.05 % or more of PP fiber was mixed. After the fire resistance experiment, the plain showed 5.5 % of mass loss rate when fiber was not mixed and others could not be measured. According to increase in mixing ratio of fiber, river sand with fineness modulus of 2.2 showed most satisfactory result of 34 %${\sim}$42 %. Mass loss rate after fire resistance experiment was most satisfactory at about 10 % in the plain crushed sand without mixing of fiber, and all other mixes with 0.05 % PP fiber or more showed 5${\sim}$10 % loss rate.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.73-76
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• 2005

This study aims to suggest a simple and convenient design for a mix proportion method for high performance concrete by determining the optimum fine aggregate ratio and minimum binder content based on the maximum density theory. The mix design method introduced in this study adopted the optimum fine aggregate ratio with a minimum void and binder content higher than the minimum binder content level. The research results reveal that the method helps to reduce trial and error in the mixing process and is a convenient way of producing high performance concrete with self filler ability. In an experiment based on the mix proportion method, when aggregate with the fine aggregation ratio of 41$\%$ was used, the minimum binder content of high performance concrete was 470kg/$m^{3}$ and maximum aggregate capacity was $0.657m^{3}/m^{3}$. In addition, in mixing high performance concrete, the optimal slump flow to meet filler ability was 65$\pm$5cm, V load flow speed ranged from 0.5 to 1.5.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.373-376
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• 2008

The objective of this study is to investigate the properties of fresh concrete with recycled fine aggregates. Three different kinds of fine aggregate with natural, high and low quality recycled aggregates were prepared. The concrete mixtures were produced with test parameters of replacement ratio of recycled fine aggregate. The properties of the fresh concrete were measured by means of slump and air content according to elapsed time. Quality control method to maintain the constant total mixing water for recycled aggregate concrete was suggested. The all concrete mixtures were produced with approximately the same slump on the job site after an hour. Test results indicated that compressive strength of the concrete mixtures with constant slump is not affected by the replacement ratio of recycled fine aggregate. Therefore, the practical way for the quality control of recycled aggregate concrete is to maintain the constant total mixing water.

• KCI Concrete Journal
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• v.11 no.3
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• pp.19-28
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• 1999

This study treated self-compacting high Performance concrete as two Phase materials of Paste and aggregates and examined the effect of powder and aggregates on self-compacting high performance, since fluidity and segregation resistance of fresh concrete are changed mainly by paste. To improve the fluidity and self-compactibility of concrete, optimum powder ratio of self-compacting high performance concrete using fly ash and blast-furnace slag as powders were calculated. This study was also designed to provide basic materials for suitable design of mix proportion by evaluating fluidity and compactibility by various volume ratios of fine aggregates, paste, and aggregates. As a result, the more fly ash was replaced, the more confined water ratio was reduced because of higher fluidity. The smallest confined water ratio was determined when 15% blast-furnace slag was replaced. The lowest confined water ratio was acquired when 20% fly ash and 15% blast-furnace slag were replaced together. The optimum fine aggregates ratio with the best compactibility was the fine aggregate ratio with the lowest percentage of void in mixing coarse aggregate and fine aggregate In mixing the high performance concrete. Self-compacting high performance concrete with desirable compactibility required more than minimum of unit volume weight. If the unit volume weight used was less than the minimum, concrete had seriously reduced compactibility.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.197-198
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• 2023

This study was conducted as part of research and development of high-strength grout. Accordingly, dolomite aggregate was used as a filler incorporated into the high-strength grout. Dolomite aggregate has a disadvantage of increasing the viscosity of the grout due to higher generation of fine powder than other aggregates. Accordingly, in this experiment, it was confirmed that the viscosity, flow time, and flow of high-strength grout change according to the volume composition ratio of dolomite aggregate and cement-based material. All experiments were conducted based on the Korean Industrial Standard KS F 4044, and the mixing factor was applied according to the composition ratio of the binder and the filler. In the experiment, the amount of fine powder contained in the dolomite aggregate rather than the silica sand used in the past is grasped, and after mixing with the grout accordingly, the mixture is proceeded to measure the viscosity in an unhardened state. In addition, the flow and flow time of the grout are evaluated according to the viscosity. As a result of the experiment, it was confirmed that the viscosity and flow time decreased and the flow increased as the volume composition ratio of the dolomite aggregate to the cement-based material increased.