• 한국건설순환자원학회논문집
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• 제8권3호
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• pp.302-309
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• 2020

건설폐기물 중간처리시설에서 발생하고 있는 폐슬러지를 건조 분쇄한 순환 슬러지와 재활용되지 못하는 폐유리병을 가공처리한 순환 유리골재를 순환 상온아스팔트에 적용하기 위한 기초연구로서 순환 슬러지 및 순환 유리골재의 사용에 따른 순환 상온아스팔트의 특성을 비교·검토하였다. 그 결과 순환 슬러지를 채움재로서 사용량을 증가할수록 순환 상온아스팔트 혼합물의 마샬 안정도, 간접인강강도, 인장강도비는 감소하고 흐름값, 공극률은 증가하는 것으로 나타났다. 또한 순환 유리골재를 사용함으로서 순환 상온아스팔트 혼합물의 마샬 안정도, 간접인강강도, 인장강도비는 감소하고 흐름값, 공극률은 증가하는 것으로 나타났다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.361-365
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• 1999

This study examined the effects of multiple recycling on deinkability and properties of recycled paper from laser computer printout (LCPO). First, alkaline paper with a 20% printed area was disintegrated by TAPPI standard disintegrator at room temperature. After dewatering, the pulp was flotated and dried in oven at80$^{\circ}C$ for 24 hrs. A sequence of wetting, disintegrating, flotating and drying was one recycling cycle and this cyclic treatment was repeated from zero to five times. The recycled handsheet dropped to 90% of the original brightness after five cycles, and lost the most brightness after five cycles, and lost the most brightness in the first two cycles. However, it had a gain of 10% in opacity after five cycles as the same as the case of nonprinting. And, in this study, the method for determining residual ink(toner) content in recycled handsheets ere established by means of SEM-EDX and Py-GC. The change of residual ink percentage on recycled paper showed the effect of recycling numbers on deinkability of waste paper. A slight decrease in deinkability was noted for the recycled handsheets, which may be due to the change of fiber surface free energy connected with fiber swelling.

• 펄프종이기술
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• 제46권6호
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• pp.94-102
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• 2014

The physical and chemical properties of recycled fibers from mixed waste paper are more and more deteriorated because of unknown history of recycling times. In order to improve the mechanical properties of liner paper, the recycled fibers from wasted cotton clothes were used in papermaking process, and their applicabilities were evaluated in several points of fiber modification. Thus, two kinds of fiberizing methods from waste cotton clothes were considered by using rotary sandpaper and grinder mill. Finally, the rotary sandpaper method was relatively desirable in preserving longer fiber length and fibrillated fiber surface. The recycled cotton fibers by swelling treatment with NaOH and bleaching with reductive chemicals were mixed with OCC fibers, and the handsheets were prepared to basis weight of $80g/m^2$ and evaluated the mechanical properties of paper. The fibrous properties showed outstanding results in freeness and WRV improvements by alkali treatment and high brightness by reductive bleaching treatment. The physical and mechanical properties of sheet by mixing OCC fibers and recycled cotton fibers were also highly improved in tensile, burst strength and specially folding resistance.

• Advances in concrete construction
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• 제4권1호
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• pp.27-35
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• 2016

The quantity of construction and demolition waste has been greatly increasing recently. It causes many problems to the environment. For this reason, demolition waste management becomes inevitable in order to overcome the environmental issues. The present study aims to evaluate the effects of using recycled coarse aggregate, which is generated from construction and demolition waste, on the properties of recycled aggregate concrete. An experimental investigation on the strength characteristics of concrete made with recycled coarse aggregate is presented and discussed in this paper. In this study, Portland Pozzolana Cement (fly ash based) is used instead of ordinary Portland cement. The results of this investigation show the possibility of the use of recycled coarse aggregates in the production of fresh concrete. Use of demolition waste as coarse aggregate will lead to a cleaner environment with a significant reduction of the consumption of natural resources. A comparative study on the strength characteristics of recycled aggregate concrete made with Ordinary Portland Cement and Portland Pozzolana Cement is presented and discussed in this paper.

• 펄프종이기술
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• 제45권4호
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• pp.65-74
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• 2013

In the manufacture of corrugated box, the fibrous raw materials are mainly consisted of recycled papers, such as KOCC(Korean Old Corrugated Container), kraft sack, and AOCC(American Old Corrugated Container). Among these recycled waste paper, the proportion of KOCC is relatively higher than others in fibrous raw materials. Generally, KOCC shows some poor fiber properties and contains hazardous heavy metal sources. Therefore, it is to evaluate the property of recycled paper sources for eco-friendly corrugated box manufacture. In this study, the physical and mechanical properties of 3 kinds of recycled fibers and their mixed stocks were analyzed. The environmental assessment was also evaluated by analyzing the 4 representative heavy metal contents and evaporation residues in waste papers. As the results, KOCC showed the poorest fiber qualities and had the highest heavy metal contents and evaporation residues among the recycled fibers. Finally, the mechanical strength properties were increased by decreasing KOCC proportion of mixed stock conditions. In addition, the heavy metal contents and evaporation residues were also decreased by increasing recycled AOCC and kraft sack proportion.

• 펄프종이기술
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• 제30권3호
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• pp.7-14
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• 1998

It is well known that the recycling of pulp generates a lot of fines, and cause the hornification of fiber. Both phenomena have been contributed to a limited use of recycled fiber. Among several means which can improve the properties of recycled fiber, enzymatic treatments are considered as an effective means. Thus the effects of xylanase on the properties of recycled pulp were investigated in this study Xylanase treatment showed some refining effect at a small dosage while the fines and fibrils were reduced at higher dosage as shown in the treatment with cellulase-hemicellulase. The interesting finding is that the WRV of recycled fiber treated with xylanase was higher than that treated with the mixture of cellulase and hemicellulase. Breaking length and tear index of recycled fiber treated with xylanase were also higher.

• 펄프종이기술
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• 제30권3호
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• pp.15-21
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• 1998

Crude enzymes of Trichoderma viride and Phanerochaete chrysosporium were evaluated for their effect to brightness and physical properties of recycled pulp from newspaper and corrugated container board. The brightness of recycled pulp from newspaper increased with crude enzymes from Trichoderma viride and Phanerochaete chrysosporium. The brightness of recycled pulp of corrugated container board increased with crude enzyme from Phanerochaete chrysosporium, but decreased with crude enzyme from Trichoderma viride. The Δbrightness with chemical bleaching of crude enzyme treated pulp was lower than that of heat killed enzyme treated pulp, but the final brightness of pulp was increased. Modification of recycled paper with crude enzymes can result in a substantial increase in physical properties with little no loss in pulp freeness.

• 한국도로학회논문집
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• 제14권3호
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• pp.69-76
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• 2012

최근 국내 석산에서의 골재공급이 부족해지면서, 성토재 등의 저급재료로 재활용 되던 폐 콘크리트 순환골재의 용도를 점차 구조용 콘크리트 및 도로 포장재와 같은 고급재료로 재활용하기 위한 노력이 계속되고 있다. 이러한 노력의 일환으로 정부는 2009년 순환골재 품질기준을 제정하였으며, 순환골재가 기존보다 고급재료의 용도로 활용될 수 있는 제도적 기반을 마련하였으나, 현재까지 빈배합 콘크리트 기층용으로서의 순환골재의 활용은 매우 낮은 형편이다. 본 연구는 순환골재 품질기준에 규정되어 있는 빈배합 콘크리트용 순환골재의 이물질과 관련된 품질기준의 적정성을 일련의 실험을 통하여 평가하였다. 연구결과, 빈배합 콘크리트 기층용 순환골재 내의 폐 아스콘 골재는 강도에 악영향을 초래하는 반면, 아스콘의 특성으로 인하여 순환골재의 주요한 품질기준인 비중을 높이고, 흡수율 및 마모율을 오히려 낮추는 결과를 초래하여, 전체적인 순환골재의 품질을 평가하는데 큰 방해요소로 작용하였다. 따라서 이물질 함유량 기준 중, 폐 아스콘 함유량 기준은 개선의 여지가 있는 것으로 조사되어, 그 대안을 제시하였다.

• 펄프종이기술
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• 제48권2호
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• pp.56-60
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• 2016

Neutral or alkaline papermaking provides many advantages in paper strength and processing conditions. It also provides the opportunity of using calcium carbonate fillers in papermaking. These diverse advantages have made almost all paper machines of printing and writing papers run under neutral and alkaline conditions. On the other hand, linerboard machines, which use recycled papers as a raw material, are running under acid conditions using a rosin sizing system. Because the recycled raw materials used by the linerboard industry contain significant amounts of alkaline papers, the linerboard industry has an interest in the possibility of using the neutral or alkaline papermaking opportunity. In this study, the compatibility of the recycled linerboards under neutral or alkaline papermaking conditions was examined by recycling them under various pH conditions. The sizing degree of the papers recycled under neutral or alkaline was significantly lower than that of acid formed papers indicating that during the neutral or alkaline recycling process the rosin sized papers lost their sizing efficiency. Recycling of acid formed linerboards under neutral or alkaline conditions increased the amount of foam, and the foam contained substantial amount of solid materials derived from the acid sizing systems. Use of cationic polyelectrolytes including PEI and poly-DADMAC improved the sizing degree of the recycled papers under neutral and alkaline conditions. PEI decreased the foam generation as well while poly-DADMAC did not show any reducing effect of the foam. These results suggest that PEI forms coordinate bonds with rosin acid and precipitate them onto the surface of recycled fibers, while the reaction products between poly-DADMAC and rosin acid ions still remain water soluble under neutral or alkaline conditions.

• 한국포장학회지
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• 제18권1_2호
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• pp.27-32
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• 2012

본 연구에서는 식품포장재로 이용되는 재활용 및 비재활용 종이류가 안전한지를 평가하기 위해 식품공전 규격에 준하여 실험하였다. 식품포장재 중에서도 피자상자를 선택하였는데, 이는 피자가 고온에서 조리되어 포장되며 다량의 기름 성분을 함유하여 오염물질이 이행될 가능성이 상대적으로 높을 것으로 예상됐기 때문이다. 식품공전에서는 PCBs, 납, 카드뮴, 수은, 6가크롬, 비소, 포름알데히드 및 형광증백제의 허용 잔존농도를 정하여 식품포장재로 이용되는 종이류에 잔존하는 유해물질을 규제하고 있다. PCBs의 여섯개의 표준품과 모든 시료의 피크가 일치하지 않았으므로 피자상자에는 PCBs가 잔존하지 않는 것으로 판단된다. 카드뮴, 수은, 6가크롬에 대한 재질규격 평가를 위한 분석이 추가적으로 필요하다고 사료된다. 비소와 납은 모든 시료에서 기준치의 10배 이하의 양이 검출되어 식품포장재로 사용되었을 때 안전성에 큰 영향을 미치지 않을 것으로 판단된다. 포름알데히드는 모든 시료에서 기준치보다 낮은 농도로 검출되었지만 잉크를 많이 함유하고 있는 표면에서 미량이지만 상대적으로 높게 검출되었다. 형광증백제는 비재활용 종이 소재의 상자에서는 검출되지 않았다. 그러나, 상자 내 피자 포장 유무나 잉크의 함량 정도에 상관없이 재생용지로 만들어진 상자 시료에서는 형광증백제가 검출되었다. 형광증백제는 불검출이 기준이므로 포함된 재활용지를 식품 포장으로 이용할 때는 식품과의 직접 접촉을 피하기 위해 중간에 안전성이 입증된 간지 등을 삽입하는 방법을 사용하여 최종 식품의 안전성에 영향을 주지 않는 것이 바람직할 것이다.