• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.2
• /
• pp.116-121
• /
• 2019

In order to evaluating applicability of RAP (recycled aggregate powder) in mortar, in this study, physical and mechanical tests was carried out. Material characteristics of recycled aggregate and RAP were evaluated and the mechanical properties of mortar replaced with RAP were analyzed. Test result of sieve analysis showed that as the milling time increased the fineness modulus was decreased and the distribution of 0.6 mm particle size was found to increase. The fluidity of mortar mixture substituted with RAP tended to increase than Plain mixture. It was result that the increasing fluidity was affected by unreacted surplus water in the mortar as the binder was replaced with RAP. From the compressive strength result of the mortar subjected to RAP, it was found that the RAP was able to replace up to about 10% of unit binder weight although the compressive strength of mortar was decreased as the RAP replacement increased. From the above study, it can be concluded that the physical properties of RAP satisfied the quality standard of aggregate for replacement with fine aggregate. Moreover, in case of the RAP was replaced up to 10% of unit cement weight, it was able to be possible to improve fluidity and compressive strength of mortar.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.4
• /
• pp.349-357
• /
• 2019

Controlled low strength material(CLSM) has been developed using variety of material such as excavated soil, industrial by-product and industrial waste. But theses research limited at laboratory test and failed at commercialization. So in this paper evaluates CLSM used excavated soil characteristics such as flowability, bleeding rate, early strength for following process and 28day strength for re-excavatability. Also, various mix proportion of CLSM by water-binder ratio and soil-binder ratio were evaluated in laboratory. And derive the optimized CLSM mix proportion for using at field application test by movable batch plant. After applying CLSM at trench, evaluate core sample strength and excavatability by shovel, pickax and excavator for verify re-excavation. Furthermore, measure the level change after casting CLSM to inspect subsidence stability. As results of these assessments, not only confirmed the characteristics of CLSM at field but the fillability around pipe and subsidence stability.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.3
• /
• pp.167-173
• /
• 2018

In general, calcium is required for the reaction of blast furnace slag fine powder and fly ash. The by-products generated during the process of producing recycled aggregates have different calcium contents depending on the crushing stage and the possibility of using the process by-product as a concrete mixture is also different. In this study, the effect of the calcium content of the by-products on the compressive strength was investigated and the block was fabricated by using this. To utilize the by-products as an admixture, the calcium content was analyzed and the bending strength and surface temperature were measured according to the shape of the water storage block. As a result of this study, the possibility of making a block using recycled aggregate by-products was verified and arch type block was constructed to secure storage capacity and bending strength. Also, the surface temperature of the water storage block was reduced by $9^{\circ}C$ or more than that of the general permeable block.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2003.04a
• /
• pp.58-63
• /
• 2003

폐쇄형 묘생산 시스템(closed system for transplants production)은 자연광이 투과되지 않도록 단열재로 구성되어 있어 시스템 내부와 외부의 공기, 물, 열 등의 교환이 기본적으로 제한된다. 또한 식물 생육에 필요한 관수량, 내부에 적절한 습도를 유지시켜 주기 위한 가습량 및 공조기구에 의한 제습량 등이 시스템 내에서 평형을 이루며 순환한다. (중략)

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.3
• /
• pp.94-101
• /
• 2011

In this study, in order to develop organic-inorganic hybrid packaging materials(PM) of bike paths using blast furnace slag(BS) as industrial by-products, fundamental properties of organic-inorganic hybrid packaging materials were performed. Test result, the increase of Acryl emulsion polymer(AEP)/binder(B) ratios tends to delay the setting time, to increase the table flow, to decrease the strength by material segregation and to increase the length change. The optimal mix proportion of AEP decides on 40%(AEP/B) due to workability and high strength. The increase of BS replacement ratios also tends to delay the setting time, to separate AEP from B and to decrease the strength by material segregation. When BS replacement ratios were lower than 40%, they are satisfied with goal properties.

• Resources Recycling
• /
• v.31 no.3
• /
• pp.40-52
• /
• 2022

This study analyzed the amount of carbon dioxide reduction and economic benefits of detailed processes of CO₂ 6,000 tons plant facilities with mineral carbonation technology using carbon dioxide and coal materials emitted from domestic circulating fluidized bed combustion power plants. Coal ash reacted with carbon dioxide through carbon mineralization facilities is produced as a complex carbonate and used as a construction material, accompanied by a greenhouse gas reduction. In addition, it is possible to generate profits from the sales of complex carbonates and carbon credits produced in the process. The actual carbon dioxide reduction per ton of complex carbonate production was calculated as 45.8 kgCO₂eq, and the annual carbon dioxide reduction was calculated as 805.3 tonCO₂, and the benefit-cost ratio (B/C Ratio) is 1.04, the internal rate return (IRR) is 10.65 % and the net present value (NPV) is KRW 24,713,465 won, which is considered economical. Carbon mineralization technology is one of the best solutions to reduce carbon dioxide considering future carbon dioxide reduction and economic potential.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1756-1760
• /
• 2004

Circulating Fluidized-Bed (CFB) boilers which have been operated in Korea were manufactured by the design technology of foreign leading companies. As they are not active to transfer their technology, domestic companies don't have the enough ability to design it independently yet. Doosan Heavy Industries & Construction Co. Ltd. and Korean Institute of Energy Research are trying to develop and improve the particle re-circulating device among the components of CFB boiler. Our purpose is to control the amount of particles leaving the re-circulating system by adjusting utility air and reuse the heat of circulating particles. The results of experiments with cold model system show that a fluidization state in the particle re-circulating device is very stable when the amount of utility air is supplied to its wind box with 2.29 times of minimum fluidization velocity. Also the amount of particles entering the riser don't increase linearly when the amount of utility air is supplied over 2.5 times of minimum fluidization velocity. Now we are testing its functional run with the hotstate experiment set-up.

• Clean Technology
• /
• v.18 no.1
• /
• pp.111-119
• /
• 2012

These days many companies are trying to reduce, recycle and reuse their wastes. Even though many wastes can be recycled, those are incinerated or landfilled. To solve these problems, there are many projects to make efforts to recycle wastes in especially the industrial complexes. But, due to the absence of information about waste recycling, recyclable wastes are still incinerated or landfilled. Based on these research background, this study aims to suggest the evaluation methodology of the $CO_2$ emissions and cost reduced by circulating the industrial waste to resource. We evaluated the environmental and economic effect between companies which emit the plastic waste and organic solvent waste and use them as raw-materials in the off-line recycling information exchange network. The environmental and economic aspects were analyzed comparing waste recycling with waste incineration. By recycling the plastic waste as raw-materials, $CO_2$ emission were reduced 1,070 ton in 2009 and 1,234 ton in 2010 and 657.4 million won in 2009 and 755.0 million won in 2010 were reduced. In recycling the organic solvent waste, 7.3 ton-$CO_2$ in 2010 and 5.6 ton-$CO_2$ in 2011 were reduced and 15.9 million won in 2010 and 12.2 million won in 2011 were reduced.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.148-148
• /
• 2023

산업 고도화로 인하여 복잡하고 다양한 유기물의 사용량이 증가하였으며, 공공수역 내 새로운 오염물질이 유입됨에 따라 생화학적 산소요구량(BOD) 중심의 수질평가에 한계를 나타내었다. 이후 난분해성 물질을 고려한 유기물관리 정책과 총량관리의 필요성이 제기되었고 국내 하천과 호소에서는 총 유기탄소(TOC)를 유기물 관리지표로 설정하였다. 그러나 부영양 하천과 호소에서 TOC는 외부 부하뿐만아니라 식물플랑크톤의 과잉성장에 의해 증가할 수 있는 항목이므로 TOC 관리정책 추진을 위해서는 유기물의 기원에 대한 파악이 필요하다. 한편, 우리나라와 같이 몬순 기후대에 속한 댐 저수지의 경우 강우시 유입하는 탁수에 의해 다량의 유기물과 인이 유입되기도 하지만 식물플랑크톤의 제한요인 중 광량에 많은 영향을 미친다. 식물플랑크톤의 광합성은 수체 내 유기탄소 내부생성에 매우 중요한 요소이나 점 단위의 실험적 방법을 활용한 유기탄소 순환 해석은 저수지의 시·공간적인 변동성을 고려하기에 한계가 있다. 본 연구의 목적은 금강 수계 최대 상수원인 대청호를 대상으로 3차원 수리-수질 모델을 적용하여 유기탄소 성분 별 유입과 유출, 내부생성 및 소멸량을 평가하고 탁수가 저수지에서의 유기탄소 순환에 미치는 영향을 분석하는데 있다. 유기탄소 물질수지 해석을 위해 AEM3D 모델을 사용하였으며 2018년을 대상으로 입력자료를 구축한 후 보정 및 검정을 수행하였다. 모델은 유기탄소를 입자성, 용존성, 그리고 난분해성과 생분해성으로 구분하여 모의하며 유기물질 성상별 실험결과를 이용하여 입력자료를 구축하였으며 유기탄소순환 해석을 위해 4가지의 탄소성분과 조류 세포 내 탄소의 질량 변화율을 계산하였다. 이를 위해 외부 유입·유출부하율, 수체 내 생성(일차생산, 재부상, 퇴적물과 수체 간 확산) 및 소멸률(POC 및 조류 침강, DOC 무기화, 탈질)을 고려하였으며 탁수의 영향을 분석하기 위해 탁수 포함여부 시나리오를 구성하고 유기탄소 생성 및 소멸기작별 변동성을 비교 분석하였다. 모델은 2018년의 물수지를 적절히 재현하였으며 저수지의 수온 및 탁도 성층구조를 잘 재현해내면서 전반적인 수질을 적절하게 모의하였다. 탁수를 고려하였을 시 연간 TOC 부하량 중 내부기원 부하량은 56% 수준이였으나 탁수를 배제한 경우 내부기원 부하량은 82%로 나타났다. 특히, 연평균 Chl-a 농도가 44~48% 차이가 발생하면서 1차생산량이 약 4배가량 증가하였다. 몬순지역에서의 탁수는 체류시간이 긴 성층 저수지에서 식물플랑크톤 성장제어에 큰 영향을 미쳤으며 전반적인 유기탄소 순환을 해석하는데 있어 매우 중요한 인자로 작용하였다.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.4
• /
• pp.341-348
• /
• 2023

In this study, in order to minimize the increase in the amount of various industrial by-products due to the rapid growth of the industry and the intensification of the depletion of natural aggregate resources, the material test using recycled aggregate and steelmaking slag and the proper mixing ratio of recycled concrete were to be derived. In this study, first, the conformity of the quality standards of the materials used in the field was confirmed, and the workability and molding results were shown when used alone or mixed. Therefore, the feasibility of application as aggregate for concrete was evaluated through a total of 4-type mixtures of cement types, admixtures, coarse aggregates, and fine aggregates. As a result of the experiment, it was confirmed that the slump of unhardened concrete, the amount of air, chloride and compressive strength of hardened concrete according to the replacement rate were different from the measured values of general concrete quality characteristics. According to this, it was confirmed that the quality characteristics of the standard design criteria were satisfied.