• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.90-100
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• 1995

This study was performed to develop the lightweight concrete using synthetic lightweight aggregate and natural coarse aggregate. Mixing ratios were three types, the first type was mixed cement and synthetic lightweight fine aggregate (Type CP), the second type was mixed cement, synthetic lightweight fine aggregate and synthetic lightweight coarse aggregate (Type CPE), the third type was mixed cement, synthetic lightweight fine aggregate and natural coarse aggregate (Type CPN). The results of this study are summarized as follows ; 1. The W/C of each mixing ratio was increased with increase of the amount of cement used, and it was shown higher in order of Type CP, CPN, CPE. 2. The unit weight of Type CP, CPE and CPN was 1.473~1.647g/cm$^3$, 1.467~1.622g/cm$^3$ and 1.658~1 .838g/cm$^3$, respectively. And the absorption ratio was approximately 20%, which was higher than that of the normal cement concrete. 3. The compressive strength of Type CP was shown 178 ~249kg/cm2, Type CPE was shown 149~241kg/cm$^2$ and Type CPN was shown 196~297kg/cm$^2$, respectively. Each strength ratio was smaller than that of the normal cement concrete. 4. The pulse velocity of Type CP, CPE and CPN was 2, 688~3, 240m/sec, 2, 981~3, 324m/sec and 2, 989 ~ 3, 545m/sec, respectively. And it was increased with increase of strength and unit weight. 5. The length change ratio at 28 days was in the range of 0.057~0.077%, and earlier length change ratio was higher than that of the later.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.219-225
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• 2018

The aim of the research is improving the quality of concrete by using the alternative aggregate resources and recycling wastes. To make a combined aggregate fitted in standard particle size distribution curve, crushed sand from blasted rock debris was used as a base aggregate. Additionally, to increase the portion of fine particles, sea sand was mixed. Although these aggregate combination fit the standard particle size distribution curve, in this research, raw coal ash was replaced as a microfine. According to the experiment, by replacing 5% raw coal ash, the most favorable results were achieved in aggregate gradation and cement mortar quality.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.81-82
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• 2012

The purpose of this study is the hydration properties of motar using Blast-Furnace Slag(BFS) with water elured from recycled coarse aggregate. The results of the experiment show that the water eluted from recycled coarse aggregate mixed with blast furnace slag has comparatively higher hydration activity than the mortar not mixed with one in early-age mortar causing the calcium hydroxide in the recycled coarse aggregate to work on as a stimulus to the hydration of ground granulated blast furnace slag. BFS mixed with the eluting water the hydration reaction was a promotion.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.93-99
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• 2000

The physical properties of freshly mixed steel fiber reinforced recycled concrete(SFRRC) were_investigated. Physical state and quality of fresh concrete were monitored batch by batch. the properties of freshly mixed SFRRC were determined in terms of slump, air content, superplasticizer, and bleeding ratio. Concrete mixtures were produced for three kinds of aggregate proportions. So, the experimental variables are various aggregate proportions, steel fiber contents(0, 0.5, 1.0, 1.5%) and steel length(30, 50, 60mm). From experimental results, optimum s/a by various experimental variables, variations of the slump by the air contents, and optimum superplasticizer to decrease unit water were presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.37-38
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• 2016

In this study, it evaluate the coarse aggregate mixed effect to impact resistance performance of the fiber reinforced cement-based material. The type of fiber is Hooked-ended steel fiber, and mixed 1vol.% in concrete and cement composites. The impact experiment was conducted by using a spherical shape projectile diameter of 25mm to 170m/s speed and Impact resistance performance was evaluated by measuring the fracture grade, fracture diameter and depth.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.79-80
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• 2019

This study was intended to examine the possibility of reducing hydration heat by FA substitution and combination of slag (CGS) from coal gasification power generation (IGCC) with mixed aggregate for concrete. The analysis results showed good results if liquidity increases as the ratio of CGS increases, air volume decreases, and compressive strength is mixed up to 25% in the residual aggregate. The results showed that the heat of hydration was reduced compared to plain due to the boron content of CGS as the CGS substitution rate increased, but it was larger due to the combination with FA substitution. It was found that the heat of hydration was reduced.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.327-328
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• 2021

In the manufacturing process of ready-mixed concrete, quantity management directly affects the workability and strength of concrete. Therefore, water quantity is the most important management factor for water quality control of ready-mixed concrete. It can be said that the number of unit water in the mix design, the water quantity due to the surface water contained in the aggregate used, and the water quantity taking into account the concentration of sludge contained in the recycling water when using the recycling water are factors that affect the quantity management of ready-mixed concrete. In this study, as a stable quality control method of ready-mixed concrete, a quantity management method by aggregate surface water and a sludge concentration management method according to the use of recycling water were proposed. Thus, we tried to suggest an efficient quantity management method for stabilizing the quality of ready-mixed concrete.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.5-11
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• 2017

The 19 mm-sized aggregate was produced by melting vinyl waste (waste polyethylene film) generated from vinyl greenhouses in rural areas. It was mixed with As'cone at various weight ratios, and then insulation effect test, tension test after repeated freezing and thawing, ice pull-out strength test and field density test were conducted for the mixtures. These results demonstrated that as the mixing ratio of polyethylene aggregate increased, the insulation effect increased, due to the many pore spaces that existed in the polyethylene aggregate. After repeatedly freezing and thawing As'cone, the tensile strength significantly increased at 2.5% of the polyethylene aggregate content rather than 0% of polyethylene aggregate content but it also slightly decreased at 5% and 10% of polyethylene aggregate content in comparison to 2.5% of its polyethylene aggregate content. As'cone added with polyethylene aggregate by 2.5% resulted in lower ice pull-out strength than that of normal As'cone. As a result of the porosity test for the samples taken at the site, porosity of the As'cone, which added polyethylene aggregate, was smaller than that of the general As'cone.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.138-139
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• 2014

In this study, conventional aggregate obtained from a ready mixed concrete factory and the aggregate with a modified grading produced in lab. condition were prepared. Results showed that a good grading of aggregate the ratio of 5~13 mm and 13~25 mm is 20~40 % produced in the lab. condition significantly improved the slump and the compressive strength of the concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.113-116
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• 2008

In these days, properties of concrete has been demanded to be high performance because concrete structure was bigger and higher. So studies on high strength concrete and lightweight concrete has been frequently done. But lightweight concrete has been used to limited non-structural elements in th country. Lightweight aggregate mixed with lightweight concrete was only coarse aggregate in case of the structural lightweight concrete. In the country studies on the lightweight concrete was poor and unvaried. Also it is difficult to be practical use of lightweight concrete was that it has been expensive. It was study on the using fine lightweight aggregate with lightweight concrete to crushed by-products and wastes to get to make foamed glass with recycled glass. So it was tested by fine aggregate standard and mixed with.