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%.

관광지 및 공공공간에서의 사인 시스템은 대상지에서의 즉각적이고 명확한 정보 안내는 물론 현장에서의 다양한 이용자 계층을 고려한다는 측면에서 여전히 중요한 과제로 남아 있다. 본 연구는 대표적 한국전통문화 관광지의 하나인 한국민속촌을 대상으로 정체성, 통일성, 가독성, 내구성, 위치의 적합성 등 5가지 조성원칙에 입각하여 문제점을 분석하였다. 이를 위해 사인시스템에 대한 문헌분석, 한국민속촌 사인시스템의 현황조사와 더불어 실제 이용자 150명을 대상으로 현장 설문조사를 실시하였으며, 이를 바탕으로 각각의 조성원칙이 전반적인 사인 이용 만족도와 어떤 상관성을 갖는지에 대해 분석하였다. 정체성, 통일성, 가독성, 내구성, 위치의 적합성 등 사인시스템의 5가지 주요 원칙들과 사인의 이용만족도와의 상관관계를 파악하기 위해 Pearson 상관계수 분석을 실시하였으며 그 결과, 한국민속촌의 경우 통일성과 가독성이 사인의 이용만족도와 통계적으로 유의한 상관관계가 있었으며 내구성과 위치의 적합성은 사인의 이용만족도와 낮은 상관성을 보였다. 5개의 주요 요소들간에는 정체성과 통일성이 가장 높은 상관관계를 보였으며, 통일성과 가독성, 정체성과 위치의 적합성도 유의한 상관관계를 나타냈다.

PURPOSES: The objective of this study is to evaluate the properties of high-performance concrete and compare them with the properties of ternary blended cement (OPC 60% : BFS 30% : FA 10%) as applied to all-in-one bridge decks. High-performance concrete modified with styrene-butadiene latex (SB latex) was evaluated for strength development and durability through its compressive strength and chloride ion diffusion coefficient. METHODS: The compressive strength test was conducted according to KS F 2405, and the average value of the three specimens was used as the result at each stage. The chloride ion diffusion test was performed at 28 days, 56 days, and 365 days according to NT BUILLD 492. The chloride ion penetration test was conducted according to ASTM C 1202. RESULTS: For the compressive strength of the high-performance concrete, the blast furnace slag 40% replacement (BFS40) mixture had the most similar results to those of the ternary blended cement. The BFS40 mixture exhibited a lower compressive strength at 3 days than the latex modified concrete (LMC) mixture used for the bridge deck pavement, whereas it exhibited a 3.7-9.8% higher compressive strength at 7 days. In addition, the BFS40 mixture had the lowest diffusion coefficient, which was 49.1~59.0% lower than that of the LMC mixture. Mixing with latex tended to decrease in charge passed compared to Plain which is only used ternary blended cement, and showed excellent watertighness (rated “very low”), which is lower than 1,000 coulombs in all mixtures with latex. CONCLUSIONS : The BFS40 mixture exhibited excellent compressive strength, chloride ion permeability resistance, and the lowest chloride ion diffusion coefficient although it included a small amount of latex, which makes it more expensive than the current LMC mixture. It is believed that it is possible to secure excellent economic efficiency and durability by using lesser latex than that in the LMC mixture and using a mixture of the blast furnace slag instead.

In this paper, the boom of a 30m class refracted insulation with outrigger on aerial elevating work platform is modeled as 3D CAD program of CATIA. The static and dynamic analyses are performed by using ANSYS and ADAMS programs, respectively. The refracted insulation boom uses acetal and the composite boom for insulation. And the composite insulation boom is modeled by using ACP (Ansys Composite Prepost) of ANSYS program. In order to analyze the durability of refracted insulation boom, the static analysis is performed and each analyzed part is stored as =MNF-type flexible body model. The dynamic analysis is performed with ADAMS by using the flexible model. As the result, these analyzes clarify the structural stability and dynamic durability (hot spot) of the refracted insulation boom.

Chlor-alkali (CA) membranes as key materials to generate chlorine gas and sodium hydroxide are composed of sulfonic acid layer (S-layer) and carboxylic acid layer (C-layer) to provide fast sodium ion transport and slow hydroxide ion diffusion, respectively. Aciplex F, a representative CA membrane is made in a double layer form via thermal adhesion of both layers after each single layer film is independently fabricated. Unfortunately, the membrane fabrication induces delamination particularly in their interface as a result of hydroxide ion diffusion occurring during CA operation, leading to rapid increase in electrochemical overpotential. In this study, selective chemical conversion technique was developed to solve the delamination issue. Their effectiveness was proved by applying the same concept to a wide range of PFSA membrane.

Saline water electrolysis (SWE) is an electrochemical technology to directly generate valued chemicals such as chlorine gas (Cl2), hydrogen (H2), and sodium hydroxide (NaOH) by applying electric energy. The key materials in SWE are cation exchange membranes with high selectivity to sodium ions under chemically harsh SWE conditions. The representative SWE membranes are perfluorinated double layered membranes composed of perfluorinated sulfonic acid layer and carboxylic acid layer to transport sodium ions rapidly and to prevent the passage of hydroxide ions, respectively. The commercially available membranes are, however, suffering from delamination issues occurring in their interface. In this presentation, delamination-free membrane fabrication processes will be addressed.

콘크리트관은 하수관으로 널리 쓰이지만, 중량이 무거워 취급이 곤란한 단점이 있다. 또한 하수 및 해수 지역에 매설될 경우 황산수소(H2S)와 염화물에 의한 화학적 침식 등으로 인해 균열, 단면 감소 등 각종 열화현상이 발생하게 되어 파형강관을 대신하여 사용하지만 시공특성상 파손이 생기거나 매설지역에 부등침하가 존재하거나 과도한 외부압력이 작용할 경우 누수 또는 파손이 발생하여 관거로서의 기능이 저하될 우려가 있다. 이에 본 논문에서는 3겹으로 코팅된 수지파형강관(CCSP)을 파형강관 대신 하수관에 적용하기 위한 연구를 수행하였으며 우선 CCSP를 화학약품에 침지한 후 마모율 및 중량감소 등을 통해 화학저항성을 알아보았다. 특히 해안가에 시공될 경우 장기재령 내구성능을 확인하기 위해 부산 감만항 인근에 수지파형강관을 매설한 후 재령 10년 및 15년이 경과한 시점에 피복부착력을 확인하기 위해 염수분무, 핀홀, 음극박리시험을 실시하였으며 외압에 대한 저항성을 알아보기 위해 재하시험을 실시하였으며 그 결과 모든 항목에서 KS품질 기준을 만족하고 관거로서의 소요성능을 확보하고 있어 장기재령 내구성을 확보하고 있음을 확인하였다.

PURPOSES: In order to apply high-speed weigh-in-motion (HS WIM) systems to asphalt pavement, three high-durability asphalt concrete mixtures installed with a WIM epoxy are evaluated. METHODS: In this study, dynamic stability, number of loading repetitions to reach the rut depth of 1 mm, and rut depth measurements of three asphalt mixtures at 60℃ were compared using an Asphalt Pavement Analyzer (APA). Laboratory-fabricated material and field core samples were prepared and tested according to KS F2374. RESULTS : Through the laboratory tests, it was found that all three modified asphalt mixtures (stone-mastic, porous, and semi-rigid) with WIM epoxy showed favorable permanent deformation results and passed the dynamic stability criterion of 3000 loading repetitions per 1 mm. In addition, it was confirmed that the modified SMA mixtures cored from the field construction yields satisfactory rutting testing results using the APA. Finally, the epoxy used for the HS WIM installation shows good adhesion with the three asphalt mixtures and permanent deformation resistance.

The ultimate goal of this development is a hybrid solar energy storage device. It supplies stable power to the load due to the emergency generator that compensates for the power shortage due to solar power generation. We have developed a stand-alone photovoltaic power generation and energy storage system with a dual inverter that extends the performance life of the PV system. It solves the problem of shortening the lifespan of battery due to repetition of charge / discharge of PV system and supplies stable power to load due to emergency generator that compensates for power shortage due to solar power generation, and furthermore, A stand-alone photovoltaic power generation system having a dual inverter for extending the life span and a control method thereof. We have also developed an optimized energy solution that enables us to save and use the remaining surplus power in the ESS to save energy through efficiency, optimization and substantial energy savings.

Most of the expressway concrete pavements in Korea have been constructed with jointed plain concrete pavements. However, the premature failure of joints occurred on some routes and it is considered to be related to the durability of concrete. Korea Expressway Corporation has been continuously devoting efforts to increase the durability of concrete, and recent research has shown that premature failure of jointed plain concrete pavement constructed recently has decreased. The durability of pavement concrete is determined by internal and external factors. Currently, the durability of pavements concrete is controlled by controlling the quantity and the spacing factor of internal air. In this study, the feasibility of evaluating concrete durability through absorption performance tests was examined. The absorption performance was evaluated by applying ASTM C 1585 and modified NBN B 15-215 in Belgium and applied to the pavement concrete mixed in the laboratory or collected on site. Each test is a method to evaluate water absorption performance, but ASTM evaluates the absorption performance through the upper surface and NBN evaluates the absorption performance through the entire surface of specimens. In this study, the absorption performance of the pavement concrete measured according to the test method was compared and the advantages and disadvantages of the performance evaluation method were examined through comparison of test results and procedures. As a result of the absorption performance test on the cores collected at the site, the amount of water absorption in the region where the few premature failure was occurred was relatively small. Also, the specimen of lower water cement ratio absorbed the smaller amount of water. And the small amount of aggregate at the surface showed tendency of the large absorption of the water. The amount of absorption due to the increment of air content showed a moderate increment but it was relatively small. This study has confirmed the possibility of estimating the durability through the evaluation of the absorption performance of concrete. However, further study is needed to extend the results obtained from the test method to the evaluation criteria of pavement concrete.

Currently, in Korea, the frequent damage of aged concrete pavements causes route blockages due to maintenance and repair works. Ultra-rapid cement has been used as a measure to solve the economic losses which result from traffic delays, accidents, and civil complaints due to blocked routes. However, now, it couldn’t be used except for urgent constructions because the price is expensive and its onsite application is complicated, hence, fast hardening admixtures are being used in ordinary cement to solve the problem with ultra-rapid cement. In this research, it is intended to develop a material which enables early opening of the road being constructed and cured within 24 hours of closure, to secure durability characteristics of early strength concrete by incorporating admixtures (silica fume, latex, polymer powder), and to find optimal mixing ratio and select the optimal variable for each material.

Membrane bioreactors (MBRs) have big issue on high aeration energy. In this study, reciprocation of membrane was adapted to mitigate membrane fouling. Inertial force induced by reciprocation removed foulants from membrane surface. Pilot plant with capacity of 1,100 m³/day was operated for 8 months in Singapore. The result showed stable trans membrane pressure (TMP) and low permeate turbidity below 0.1 NTU at 25 LMH. It also showed 60 times less energy consumption than conventional MBR. Low dissolved oxygen in membrane tank resulted in higher nitrogen removal. Long-term reciprocation requires very strong membrane modules. Braid reinforced membrane and its modules were optimized to reciprocation. The evaluation of them after the operation showed there was no change in all their properties.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engines are recognized as main causes of the air pollution. CRDI (common rail direct injection) diesel engine is widely used for the sake of minimization on exhaust emission. Because biodiesel fuel is a renewable and alternative fuel for diesel engine, its usability is expanded. An commercial CRDI diesel engine used to commercial vehicle was fueled with diesel fuel and 5% biodiesel blended fuel (BDF 5%) with city mode in excess of 300 hours. The engine performance and exhaust emissions were sampled at 1 hour interval for analysis. To check the engine parts (valve, injector), the engine was inspected after test. It was concluded that there was no unusual deterioration of the engine, or any unusual changes in engine power and exhaust emissions in spite of operation of 300 hours with BDF 5%.

The purpose of this study is to improve the durability by solving the crack problem of the steering gearbox bracket welded to the frame assembly. For the exact and effective analysis, we use charac- teristic(fishbone) diagram from the viewpoint of 4M1E. Through this analysis it was identified two kinds of problems, and develop improvement plan for it. Verification tests must be performed to confirm the improvement. So, the test method for steering gearbox bracket improvement was newly established by referring to similar case. As a result of the tests for verification, the stresses at crack point are decreased and the durability was improved about 2.6 times compared with product before improvement.

기존의 교면 포장이나 측구 시공에 적용한 건설재료들의 성능저하로 인해 유지보수비가 증가하고 있는 추세이다. 이에 본 연구에서는 현장 실험을 통해 개질유황 콘크리트의 내구성을 평가하는데 있어 기존의 고정형 팬믹서와 건 비빔 시 자전속도 변환이 가능한 가변형 팬믹서를 이용하여 내구성 평가 시험으로 콘크리트의 압축강도 시험을 수 행하였다.

PURPOSES : It is necessary to prevent premature failure of concrete pavements caused by durability problems. The purpose of this study was to find factors affecting the durability of concrete pavements, and suggest improvement methods for existing concrete mix design. METHODS: Factors influencing durability were derived from laboratory test data for common field failure conditions and main properties of concrete cores taken from the field. The improvement of concrete properties was investigated by evaluating the performance of existing and proposed mix proportion designs and curing methods. RESULTS: The compressive strength and the absorbing performance of the low Blaine cement and the high-strength mixture were better than those of the TypeⅠcement. Wet curing showed better compressive strength, elastic modulus, coefficient of thermal expansion, and absorption performance than air curing or compound curing. As a result of comparing concrete cores collected in the field, the sections with good durability showed good performance in terms of resistance to chloride ion penetration, absorption, and initial absorption rate. CONCLUSIONS: The absorption performance was considered as a possible foactor affecting durability of cement concrete pavements as a result of field core tests. In order to improve the durability of the pavement concrete, it is necessary to improve the existing mixtures and curing methods.