• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.71-74
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• 2001

AMB(Acid Mine Drainage), characterized as high concentration of metal & sulfate ions and low pH(2.0~4.0), is the world-wide problem wherever there is or has been mining activities. Though limestone has been generally used to neutralize AMD, There are metal hydroxide precipitation on the surface of limestone and excessive alkalinity formation which exceeds the regulation. In this research, concrete-recycled fine aggregate is selected for alternative neutralizing agent. Because fine recycled aggregate had more ANP than others in the preliminary research, the purpose of this research is to apply fine aggregate for AMD neutralization. Three columns packed with fine aggregates(2.5mm$O_3$) of it is calculated as 0.09(C-1), approximated 10% purity of limestone. Comparing with values of other columns(C-2: 0.01 and C-3: 0.01), there is variation of porosity and residence time induced from the precipitation of metal hydroxide. Consequently, 8 hours of HRT is enough to create adequate alkalinity and the function which could expect the variation of porosity(n) and residence time( $t_{R}$) should be applied to develop design function.lied to develop design function.

• 대한환경공학회지
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• 제27권5호
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• pp.486-490
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• 2005

본 연구에서는 일반(천연)모래를 대체하여 폐콘크리트 재생잔골재(이하 재생모래)를 하수관거 모래기초용 재료로 활용하였을 경우 재생모래의 지반적 거동(침하)에 대한 다양한 적용성 평가를 실시하였다. 이를 위해 상대적 재료 특성 차이에 따른 침하량 전산모사(FLAC 사용)를 실시하였으며 실내 재하 실험을 통한 즉시침하 평가, 우수에 의해 예상되는 재료특성 변화를 살펴본 후 실규모급 현장 적용성 평가를 실시하였다. 그 결과 FLAC으로 예측된 재생모래기초의 침하량은 $5.0{\times}10^{-6}\;m$ 미만이었으며, 실내 침하실험에서는 침하가 발생되지 않았다. 또한 용출에 인한 재료특성(흡수율 등) 변화 역시 미미하였다. 마지막으로 실규모급 현장 시공의 침하 모니터링 결과, 원지반의 압밀침하로 예상되는 5 mm의 침하만이 발생하였다. 이를 통해서 재생모래의 하수관 모래기초 적용성은 충분한 타당성을 가지는 것으로 판단된다.

• 한국도로학회:학술대회논문집
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• 한국도로학회 2002년도 학술발표회 논문집
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• pp.89-92
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• 2002

본 연구의 목적은 여러 가지의 폐자원중 슬래그 및 폐주물사의 도로포장용 골재로서의 특성을 평가하고, 이를 이용한 다양한 조합의 재활용 아스팔트 혼합물의 소성변형 특성을 평가하는 것이다. 골재특성을 평가하기 위해 입도 및 입형분석, 비중 및 흡수성, 마모저항성, 골재안정성과 같은 시험을 수행하였다. 골재로서의 특성평가 시험 결과 고로슬래그는 비교적 강도 특성이 제강슬래그에 비해 작은 경향을 나타냈다. 마샬배합설계로서 최적 아스팔트 함량이 결정되었고, 그 범위는 7.2%에서 7.5%정도 였다. 재활용 골재를 이용한 조합의 아스팔트 혼합물의 소성변형 특성을 평가하기 위해 간접인장강도시험, 회복탄성계수시험, 크리프 시험을 수행하였다. 재활용 골재를 이용한 아스팔트 혼합물의 소성변형 특성이 일반골재를 이용한 아스팔트 혼합물에 비해 다소 떨어지는 경향을 나타내었다. 다만 현재진행중인 휠트래킹 시험 결과가 나오면 재활용 골재를 활용한 아스팔트 혼합물의 소성변형특성을 좀더 구체적으로 파악할 수 있을 것으로 판단된다.

• 한국건축시공학회지
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• 제15권3호
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• pp.257-263
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• 2015

본 연구에서는 우리나라에서 생산되는 고로슬래그 미분말(BS)의 품질특성과 BS의 치환율 변화가 순환골재 사용 시멘트 모르타르의 공학적 특성에 미치는 영향 및 BS 품질 특성치와 모르타르의 공학적 특성치간의 상관성을 분석하고자 하였다. 분석결과 먼저 BS 품질특성은 9개 항목 중 4개 항목에서 불만족하는 공장이 존재하였는데, 이중에서도 분말도의 개선이 제일 중요하게 요구되었다. 또한, BS의 치환율이 증가할수록 순환골재사용 시멘트모르타르의 유동성은 증가하였으나 응결지연, 초기강도가 저하하는 문제는 존재하였으나, 단 잠재수경성반응으로 후기재령에서는 증가하였다. BS의 품질특성치와 시멘트 모르타르의 공학적 특성치간의 관계에서 이수석고와 관련하는 $SO_3$ 및 L.O.I는 응결시간, 3 및 91일 압축강도와 미약하지만 어느 정도 상관성이 있는 것으로 분석되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.793-797
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• 2005

This study was undertaken to examine the feasibility of recycling waste concrete fine aggregate to prepare polymer-modified mortars. The specimens of polymer-modified mortars were prepared by using styrene-butadiene rubber(SBR) latex and polyacrylic ester(PAE) emulsion as a polymer modifier. The formulations for specimens were prepared with various replacing ratios of waste concrete fine aggregates as parts of standard sand and various polymer cement ratios. For the evaluation of the performance of polymer-modified mortars, various physical properties were investigated. As a results, water cement ratio of polymer-modified fresh mortars increased with an increase of recycled fine aggregate, but decreased with an increase of polymer modifiers. The compressive and flexural strengths of polymer-modified mortars decreased with an increase of recycled fine aggregate, but flexural strengths increased with an increase of polymer modifiers.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.37-38
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• 2013

The fine powder obtained from the manufacturing process of recycled coarse aggregate contains unhydareted cement particles on their surface. It is believed that the alkalinity of the powder (11.0-12.5) is enough to active the slag-based composites. In this paper, the obtained powder was sieved and divided into two sizes, i.e., 0.08 mm and 0.3 mm, and added to the slag-based mortar. Results showed that the fine powder had an effect on the slump and the compressive strength of slag-based composites. With the different pH values of the powder, it could be seen that the distance between the two level powders. And found the peak 28 days compressive strength as the replacement ratio of the recycled aggregate powder changed. The findings from this study provide an indication that with achieved compressive strength, the fine powder can be used in a light weight concrete.

• 한국건설순환자원학회논문집
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• 제12권2호
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• pp.188-195
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• 2024

최근 환경문제와 골재난의 해결방안으로 건설폐기물을 재활용한 순환골재의 사용이 주목받고 있다. 순환골재의 재활용을 촉진하기 위해 마련된 여러 다양한 방안에도 불구하고, 순환골재는(특히 순환잔골재) 일반골재에 비하여 품질이 떨어지기 때문에, 구조체용 골재로서의 사용은 제한되고 있어, 순환골재 품질 향상에 관한 연구가 시급하다. 본 연구에서는 순환잔골재 품질 향상을 위해 1시간이라는 짧은 시간 동안 다양한 농도의 아크릴 수지 수용액에 순환잔골재의 침지를 진행하였고, 침지가 종료된 순환잔골재의 흡수율 및 진밀도 측정을 통해 적정 침지농도를 선정한 후, 모르타르 시험체를 제작하고 이의 역학적 성능을 평가하여 순환잔골재 재활용을 촉진시키는 처리방법을 제시하고자 하였다. 실험 결과에 따르면, 아크릴 수지 농도가 높아질수록 순환잔골재의 흡수율과 진밀도는 감소하였으며, 흡수율의 경우 아크릴 수지 농도 6~8 % 수준에서 가장 낮게 나타났으나, 아크릴 수지에 침지시킨 순환잔골재 모르타르의 압축강도는 이보다 낮은 농도인 4 %에서 가장 높게 나타나, 높은 농도의 아크릴 수지 사용이 모르타르 압축강도를 오히려 저하시킬 수 있음을 확인하였다.

• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.229-230
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• 2017

This study aims to achieve an enhancement in the quality of high strength concrete through a reduction in autogenous shrinkage by supplying the moisture needed for hydration through recycled aggregates that retain high amounts of moisture. The result showed that, moisture supply increased with the higher replacement rate, autogenous shrinkage dropped by up to 60 percent. Also, compressive strength was increased by up to 10 percent.

• Computers and Concrete
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• 제24권3호
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• pp.193-206
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• 2019

Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene.