PURPOSES : This study aims to analyze and summarize test results related to permeable blocks used for sidewalks and roadways as an alternative to conventional urban road pavement technology, specifically focusing on low-impact development (LID) techniques. Furthermore, it aims to provide reference data on the feasibility of current policy implementation and future policy directions through a longterm analysis of the performance and durability of permeable blocks in sidewalk and roadway construction. METHODS : The research methodology involves (1) conducting a survey on the status and actual conditions of permeability sustainability tests based on the results of permeability persistence tests conducted in Seoul over nine years, from 2013 to 2021; (2) analyzing the differences between the permeability block rating system of Seoul City and that employed by the Ministry of Environment; (3) analyzing the permeability of graded pavement sections in permeable blocks for sidewalks after three years of public use and deriving a regression analysis formula to estimate the maintenance period; (4) analyzing the permeability of pavement sections in permeable blocks for roadways after five years of public use and deriving a regression analysis formula to estimate the maintenance period. RESULTS : This study revealed significant improvements in the performance and quality control of permeable blocks since the implementation of the permeability sustainability test in Seoul in 2013. An analysis of the differences in the permeability coefficient and distribution based on the rating systems of Seoul City and the Ministry of Environment showed that rating system of Seoul City has approximately twice the permeability coefficient quality standard compared to that of the Ministry of Environment. Regression analysis indicated that the firstgrade permeable block was predicted to maintain its permeability for approximately 5.1 years, whereas the third-grade permeable block was predicted to maintain its permeability for approximately 3.1 years. In roadway-permeable block pavements, the first-grade sections maintained excellent quality conditions even after five years, and regression analysis predicted a permeability maintenance period ranging from eight to 17 years. CONCLUSIONS : The correlation analysis of the permeability coefficients based on the common usage period of permeable blocks for sidewalks and roadways presented in this study can provide more accurate estimations of commonality. However, further research under various environmental conditions is required to supplement these findings. Considering the lack of studies on permeable block commonality analysis in Korea, this study highlights the significance of conducting long-term experimental follow-up research to establish commonality prediction formulas for different usage scenarios.

일반적인 불투과형 사방댐은 제체 대부분이 콘크리트로 구성되어 분리 및 해체가 어려워 조속한 보강이 난해하다는 단점이 있다. 이러한 단점을 보완하기 위한 투과형 강재 스크린 사방댐이 제작되어 사용 중에 있지만, 강재가 부식되는 등 여러 문제를 보이는 실정이다. 이에 따라, 선행 연구에서는 강재 스크린 구조물을 내부식성이 뛰어난 GFRP로 대체하여 성능 및 안전 성을 검증하였지만, 동수압만 고려되는 등 다양한 조건이 고려되지 않은 것으로 확인되었다. 그렇기에 본 연구에서는 선행 연구 에서 수행된 GFRP 스크린 구조물뿐만 아니라, CFRP도 고려하였으며, 보다 다양한 표면 유속 별 하중 조건 및 유목, 토석류 등 과 같은 다양한 조건에서의 성능 비교 및 안전성 평가를 수행하였다. 해석 결과, GFRP와 CFRP는 강재 대비 제체에 작용하는 응력이 29.79∼91.73%가량 감소된 성능을 보이며, 이 외에도 충분한 안전성과 경제성을 겸비함을 확인하였다. 결론적으로 GFRP 및 CFPR 스크린 구조물은 강재 투과형 사방댐을 대체하여 사용하기에 충분하다고 판단되지만, 이는 수치 해석을 통한 결과이 므로 향후 실제 실험이 진행될 필요가 있을 것으로 판단된다.

기체투과막 기술을 이용하여 가축분뇨 폐기물 등으로부터 암모니아성 질소를 효과적으로 회수할 수 있다. 이는 폐기물 내 암모니아 기체가 폐기물에 함침된 기체투과막의 미세공극을 투과하여 막반대편에 도달하게 된다. 투과된 암모니아 기체분자는 막 반대편에 존재하는 용액 내 황산 등 산에 의해 포획 및 회수된다. 막 유입부 내 암모니아성 질소 제거 효과를 높이기 위해서는 우선 유입 폐기물 내 pH를 높게 유지해야 하는데 pH 상승에 필요한 염기성 약품 투입비용이 문제가 될 수 있다. 기존 연구에서는 보다 저렴한 소석회 투입하거나 폭기 혹은 질산화억제를 통해 높은 pH를 효과적으로 유지시키는 방 안이 거론되고 있다. 한편 암모니아성 질소 회수에 쓰이는 기체투과막의 재질은 적절한 내열성이나 내화학성 이외에도 소수 성을 띈다는 특징이 있으며 이를 통해 막기공을 통해 암모니아 기체를 선택적으로 투과시킬 수 있다. 향후 연구에서는 다양 한 성상을 가진 현장 폐기물을 이용하여 실증 Test를 수행하고 이를 기반으로 최적 설계/운전 조건 규명 및 경제성 제고 방안 을 수립하여야 한다.

본 논문에서는 UiO-66 입자를 합성하고, 이를 열가소성 탄성중합체인 polystyrene-block-polybutadiene-block-polystyrene (SBS) 블록공중합체 매질에 삽입하는 방식으로 CO2/N2 기체를 분리하기 위한 혼합 매질 분리막을 제조하였다. UiO-66 가 고분자 매질에서 미치는 영향을 확인하기 위해 SBS와 UiO-66의 질량 비율을 변화시켜가며 혼합 매질 분리막을 제조하였 다. 또한 UiO-66 입자의 균일한 분산을 위해서 두 차례에 걸친 초음파 처리 및 자성 막대를 이용한 물리적 혼합을 활용하였 다. 제조된 시료들은 푸리에 변환 적외분광법(FT-IR), 주사전자현미경(SEM)을 통해 확인하였다. 또한 기체 투과 성능은 time-lag method를 통해 확인하였다. 이때, UiO-66의 함유량이 증가함에 따라 혼합 매질 분리막의 투과도는 크게 증가하였지만, CO2/N2 선택도는 크게 감소하지 않았다. 가장 좋은 성능을 보인 20%의 UiO-66 입자를 함유한 분리막의 경우 663.8 barrer의 CO2 투 과도와 13.3의 CO2/N2 선택도를 보여주었다. 이러한 결과는 Robeson plot에서 순수 고분자 막에 비해 upper bound에 더 가까 운 성능을 나타냈는데, 첨가된 UiO-66가 선택도를 크게 희생시키지 않고 기체 투과도는 두 배 이상 향상시켰기 때문이다.

PURPOSES : In this study, we evaluated the quality levels of abrasion resistance and freeze-thaw resistance to the surface layer (colored layer) by using an overseas abrasion resistance test method to confirm the quality suitability of the concrete block surface for a domestic production permeable block. METHODS : In this study, a new evaluation item for increased durability apart from the quality standard of the permeable block was considered, namely, evaluation of the durability of the surface layer and the freeze-thaw resistance of the permeable block itself by EN 1338, ASTM C 779, 994, and GR 4009 (KS F 4419). RESULTS : The abrasion resistance test for the permeable block revealed that there were relative differences according to the different test methods. However, it was observed that if the ASTM C 779 test results did not meet the wear resistance quality standards, it did not satisfy ASTM C 944 and EN 1338. The ASTM C 779 test result was analyzed to have the highest objectivity and discernment, and this test method was proposed as a permeable block wear test method. In addition, the freeze-thaw resistance test method by the GR 4007 standard can be measured by strength, so it is possible to evaluate the resistance of the permeable block through this test method. CONCLUSIONS : The abrasion resistance test and freeze-thaw resistance test can contribute to the improvement of the permeable block when added to the current quality evaluation tests.

PURPOSES : This study was conducted to analyze the problems of the permeable block by objectively evaluating the quality of the permeable block and providing basic data to improve the quality and construction defect of the permeable block pavement in accordance with the continuously increasing demand of the permeable block. METHODS : In this study, we evaluated the current quality standard suitability of nine products to evaluate the current quality level of domestic production permeable blocks. The evaluation items were evaluated for surface layer thickness, block dimension, strength, and permeability coefficient, and the Korea Standard suitability for these evaluation items was analyzed. In addition, a three-dimensional finite element analysis was conducted to determine the effect of vehicle load on the deformation of block pavement structure. RESULTS : The results demonstrated that the surface layer (colored layer) thicknesses of domestically produced permeable block products were different according to the quality standards, and the dimensions were evaluated to be excellent for domestic permeable blocks currently being produced and delivered. In addition, the strength and permeability coefficient evaluation result demonstrated that all products meet the strength and permeability coefficient quality standards, but the correlation between these strengths and permeability coefficients is not high. The quality standard of strength and permeability coefficients is evaluated as being sufficiently achieved by domestic production technology. CONCLUSIONS: The intensity and permeability coefficients measured in this study were in line with the quality standards; however, the variable coefficient was found to have a significant difference in the quality control level from a maximum of 26% to a minimum 1.7%.

본 논문에서는 SBS-g-POEM 블록-그래프트 공중합체, 이온성 액체(EMIMTFSI) 및 ZIF-8 나노 입자를 사용하여 CO2/N2 기체를 분리하기 위한 혼합 매질 분리막(MMMs)을 개발하였다. SBS-g-POEM은 낮은 비용이 드는 자유 라디칼 중합 법을 통해 합성된 유연한 블록-그래프트 공중합체이다. EMIMTFSI는 SBS-g-POEM 매트릭스에 용해시켰으며, 합성된 ZIF-8 나노 입자들 역시 공중합체의 매트릭스에 분산시켰다. 제조된 시료들의 특성은 푸리에 변환 적외 분광법(FT-IR), 시차 주사 열량계(DSC), 주사 전자 현미경(SEM), X선 회절 분석(XRD)을 통해 확인하였으며, 분석 결과 각 성분들은 서로 간의 좋은 혼화성을 나타내었다. 기체 분리 성능은 time-lag measurements를 통해 확인되었으며, 537.0 barrer의 CO2 투과도와 15.2의 CO2/N2 선택도를 나타내었다. 이를 통해 첨가된 EMIMTFSI와 ZIF-8 나노 입자는 CO2/N2 선택도를 크게 희생시키지 않고 기체 투과 도를 두 배 이상 향상시키는 것으로 확인되었다.

Graphene oxide (GO), consisting of numerous oxygen functional groups and 2-D graphene sheet, has drawn intensive attention as a promising membrane material due to its molecular-sieving nanochannel and ease of scale up. However, GO membranes have generally showed a low gas permeability stemming from the high tortuosity of laminate structure. Herein, we prepared silica/GO hybrid membranes to overcome the low gas permeability of GO membrane by tuning its surface area and interlayer spacing. The size of silica nanoparticles grown on the GO nanosheets was successfully controlled by varying the concentration of silica precursor. In particular, the relationship between gas permeability of silica/GO hybrid membranes and the size of silica nanoparticles was investigated.