• 한국건설순환자원학회논문집
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• 제3권1호
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• pp.15-21
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• 2015

최근 레미콘 산업에서 골재의 안정적인 수급을 위해 과거에는 거의 사용하지 않았던 저품질의 골재를 혼합사용하여 천연골재의 일부로 대체하고자 시도하고 있다. 그러나 저품질의 골재는 건설폐기물 처리과정에서 생산되는 순환골재, 산업활동에 의해 생산되는 부산물 골재 등으로 KS 기준에 적합하지 않을 수 있는 문제점이 있다. 그러므로 본 연구에서는 부족한 골재자원의 유효한 활용을 위해 화강암 부순골재를 기본으로 순환골재, 고로 및 전기로 슬래그 골재를 단독 및 혼합사용하여 콘크리트의 기초적 특성을 비교하였다. 그 결과 슬럼프는 골재를 혼합사용한 경우 단독사용한 경우에 비하여 전반적으로 유동성이 0~10% 증가하여 단위수량이나 SP제 사용량 저감 등의 효과를 기대할 수 있어 경제적으로 유리할 것으로 판단된다. 압축강도는 골재를 혼합사용한 경우 연속입도 분포를 나타내어 콘크리트 내부의 공극을 채워 단독사용한 경우에 비하여 압축강도가 0~10% 증가하였다. 따라서 성인이 다른 골재를 적절한 비율로 혼합하여 표준입도범위를 만족하게 하여 활용하면 콘크리트의 유동성 및 압축강도의 증진 효과를 나타내어 혼합골재의 유용성을 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.107-110
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• 1999

The objective of this study is to obtain characteristics of early age pore-structure and carbonation of concrete using ground granulated blast furnace slag (GGBFS). The durability of GGBFS concrete should be evaluated for wide use of the GGBFS. As for that evaluation, an analysis on early age pore-structure characteristics of GGBFS concrete are very important, Carbonation depths of GGBFS concrete, which are known to be larger than that of OPC, are different according to replacement ratios and fineness of slag. Because sea sand as fine aggregate is much used recently, it is also necessary to analyze characteristics of carbonation of GGBFS concrete. In this study, The micro-pore structure formation characteristics of GGBFS concrete are obtained through the test of GGBFS mortars with different fineness and replacement ratio of GGBFS. The carbonation of GGBFS concrete is also investigated by acclerated carbonation test for early age GGBFS concrete.

• International Journal of Concrete Structures and Materials
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• 제18권1E호
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• pp.63-70
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• 2006

This study tested the alkali-silica reactivity of various types of crushed stones, following the specifications of ASTM C 227 and C 1260, and the results obtained from the tests were compared. This study also analyzed the effects of particle size and grading of reactive aggregate based on the expansion of mortar-bar due to an alkali-silica. The effect of mineral admixtures to reduce the detrimental expansion caused by the alkali-silica reaction was investigated based on the method specified by ASTM C 1260. The mineral admixtures used in this study were fly ash, silica fume, metakaolin and ground granulated blast furnace slag. The replacement ratios of 0, 5, 10, 15, 25 and 35% were uniformly applied to all the mineral admixtures, and the replacement ratios of 45 and 55% were additionally applied for the admixtures that could sustain the workability at these ratios. The results indicate that replacement ratios of 25% for fly ash, 10% for silica fume, 25% for metakaolin and 35% for ground granulated blast furnace slag were the most effective in reducing the expansion due to the alkali-silica reaction under the experimental conditions of this study.

• 한국농공학회논문집
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• 제56권4호
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• pp.21-28
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• 2014

In this study, evaluated ware the strength and durability of the vegetated water purification channel concrete to which recycled aggregates, hawang-toh and jute were applied. Box-Behnken method of response surface analysis in statistics was applied to the experimental design. Experimental variables are as follows, recycled coarse aggregates, hawang-toh, blast-furnace slag and jute fiber. In the experiment, conducted were the tests of compressive strength, chloride ion penetration, abrasion resistance and impact resistance the replacement rate effects of the recycled aggregates, blast-furnace slag and hwang-toh on the performance of vegetated water purification channel concrete were analyzed by using the response surface analysis method on the basis of the experimental results. In addition, an optimum mixing ratio of vegetated water purification channel concrete was determined by using the experimental results. The optimum mixing ratio was determined to be in 10.0% recycled coarse aggregates, 60.0% blast-furnace slag, 10.1% hwang-toh and 0.16% jute fiber. The compressive strength, chloride ion penetration, abrasion rate, and impact number of fracture test results of the optimum mixing ratio were 24.1 MPa, 999 coulombs, 10.30 g/mm3, and 20 number, respectively.

• Structural Engineering and Mechanics
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• 제51권1호
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• pp.1-13
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• 2014

This paper reports an experimental study into the rheological behaviour of self consolidating concrete (SCC). The investigation aimed at quantifying the impact of the varying amounts of mineral admixtures on the rheology of SCC containing natural sand. Apart from the ordinary Portland cement (OPC), the cementitious materials such as fly ash (FA), ground granulated blast furnace slag (GGBS) and micro-silica (MS) in conjunction with the mineral admixtures were used in different percentages keeping the mix paste volume and flow of concrete constant at higher atmospheric tempterature ($30^{\circ}$ to $40^{\circ}C$). The rheological properties of SCC were investigated using an ICAR rheometer with a four-blade vane. The rheological properties of self-consolidating concrete (SCC) containing different mineral admixtures (MA) were investigated using an ICAR rheometer. The mineral admixtures were fly ash (FA), ground granulated blast furnace slag (GGBS), and micro silica (MS). The results obtained using traditional workability results are compared with those obtained using ICAR rheometer. The instrument ICAR (International Center for Aggregate Research) rheometer employed in the present study for evaluating the rhelogical behaviour of the SCC is found to detect systematic changes in workability, cementitious materials, successfully. It can be concluded that the rheology and the slump flow tests can be concurrently used for predicting the flow behaviours of SCC made with different cementitious materials.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.128-134
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• 2005

This study was performed to evaluate the strength and durability properties of recycled concrete containing water - redispersible copolymer powder(WRP) and blast furnace slag powder(BSP) [RCWS]. Material used were cemente, recycled coarse aggregare, natural fine aggregate, water-redispersible copolymer powder, blast-furnace slag powder. Especially, Water-redispersible powder was used for blending with Inorganic binders such as cemente, gypsum and hydrated lime etc. First of all, Mixed ratio method of RCWS made Two Type. One was called type-1 which used to BSP content 5% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. Another was called Type-2 which used to BSP(blast furnace slag powder)content 10% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. According to the experimental results of (RCWS), Incase Type-2 at curing age 28days, Compressive strength, pulse velocity and dynamic modulous of elasticity were shown higher than Type-1 and The more WRP content increasing($0%{\sim}6%$) was the lower Compressive strength, Pulse velocity and Dynamic modulous of elasticity. Water absorption ratio was in the range of $3.85%\;{\sim}\;3.23%$, it was almost equal to Type-1, 2 but Increasing the WRP content($0%{\sim}6%$), The water absorption ratio is decreased.

• 한국건축시공학회지
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• 제13권1호
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• pp.29-37
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• 2013

In this study, a zero-cement brick is manufactured by replacing cement with recycled aggregates and blast furnace slag powder. Experimental tests were conducted with standard sized samples of $190{\times}57{\times}90mm$ (KS F 4004), and this manufacturing technique was simulated in practice. Results showed that the zero-cement brick with 0.35 W/B had the highest compressive strength, but the lowest absorption ratio. This absorption ratio of zero-cement brick with 0.35 W/B was lower than the required level determined by KS F 4004. Hence, to increase the absorption ratio, crushed fine aggregate (CA) and emulsified waste vegetable oil (EWO) were used in combination in the zero-cement brick. It was found that the zero-cement brick with CA of 20% and EWO of 1% had the optimum combination, in terms of having the optimum strength development (12 MPa) and the optimum absorption ratio (8.4%) that satisfies the level required by KS. In addition, it is demonstrated that for the manufacturing of zero-cement brick of 1000, this technique reduces the manufacturing cost by 5% compared with conventional cement brick.

• 대한건축학회논문집:구조계
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• 제34권8호
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• pp.3-11
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• 2018

In this study, total nine R/C beams, designed by the PVA Fiber with ground granulated blast furnace slag and recycled fine aggregate were constructed and tested under monotonic loading. In the material development, micromechanics was adopted to properly select the optimized range of the composite based on steady-state cracking theory and experimental studies on the matrix and interracial properties. Experimental programs were carried out to improve and evaluate the structural performance of the test specimens: the load-displacement, the failure mode, the maximum strength, and ductility capacity were assessed. Test results showed that test specimens (BSPR-20, 40) was increased the maximum load carrying capacity by 3~6% and the ductility capacity by 9~14% in comparison with the standard specimen (BSS). And the specimens (BSPR-60, 80, 100) was decreased the maximum load carrying capacity by 0~4% and the ductility capacity by 79% in comparison with the standard specimen (BSS) respectively.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.112-118
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• 2012

철강 산업에서는 고로 슬래그, 전기로 슬래그, 전로 슬래그 등 많은 부산물이 발생한다. 그 중 제강 슬래그는 일반 골재와 달리 높은 CaO와 낮은 $SiO_2$가 존재하며, 이를 시멘트와 콘크리트에 적용하게 되면 일부 알칼리 반응을 발생시키는 원인이 된다. 한편, 국내외적으로 제강 슬래그 중 전기로 산화슬래그의 콘크리트 구조용 골재로 사용하는 기준이 제정되어 사용을 장려하고 있지만, 슬래그에 대한 체적 안정성은 해결하지 못하였다. 최근에 이런 문제점을 해결하기 위하여 제강 슬래그의 고속의 공기로 냉각하는 방법이 국내에서 개발되었으며, 이를 적용할 경우 슬래그의 체적 붕괴를 야기시키는 유리 석회의 함유량을 최소화시키고 철 산화물에 대한 안정성을 갖는 것으로 보고되고 있다. 이에 본 연구에서는 철강 산업에서 발생되는 제강슬래그의 고속의 공기로 냉각한 급냉 전기로 산화슬래그의 콘크리트용 골재로서 활용하기 위한 기초 연구이다. 이를 위해 급냉 전기로 산화슬래그 잔골재의 품질 특성을 검토하였으며, 골재의 입도별에 따른 모르타르 특성을 검토하였다. 실험 결과 급냉 전기로 산화슬래그 잔골재의 특성은 아토마이저 공정에 의한 특성을 반영하고 있으며, 기존 콘크리트용 골재 입도 분포 범위에 비해 작은 입도 분포 범위를 가지는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.600-603
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• 2004

Recently, the river sands are in short supply. Gathering sea-sand will be faced with difficulty. Alternative aggregates for concrete are estimated by many researchers. The aggregates are blast furnace slag, steel slag, copper slag, ferro-nickel slag and recycled aggregate and etc. Nevertheless steel slag has been limited in practical use due to its expansibility which is occurred reaction with water and free CaO in slag. Most recently stable management method is to minimize the expansibility researched and developed. First of all, slump, air content, compressive strength and flexural strength are measured in concrete. An estimate is made of the segregation of concrete containing atomized steel slag by Image Analyser program.