Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process. In this study, the binder contents were controlled to produce the Fe foam with different pore size, strut thickness and porosity. Firstly, the slurry was prepared by uniform mixing with Fe powders, distilled water and polyvinyl alcohol(PVA) as initial materials. After slurry coating on the polyurethane(PU) foam the sample was dried at 80oC. The PVA and PU foams were then removed by heating at 700oC for 3 hours. The debinded samples were subsequently sintered at 1250oC with holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase.

PURPOSES : This study is to evaluate ASR(alkali silica reactivity) resistance of ternary blended binder adding ultra fine mineral admixture. METHODS : This study analyzes ASR expansion using ASTM C 1260 and 1567. RESULTS : This study showed that the fineness of mineral admixture had no effect on ASR expansion. The expansion of ternary blended binder(UFFA 20%+FGGBS 10%) were below 0.1%, and this binder met the ASR standard. Also when adding the CSA expansion agent, ASR expansion slightly decreased. The expansion of latex modified mixture increased by 80% comparing plain mixture. CONCLUSIONS : Ternary blended binder met the ASR standard, and this binder is available in concrete bridge deck overlay.

This study investigated a developed process for producing a composite bipolar plate having excellent conductivity by using coal tar pitch and phenol resin as binders. We used a pressing method to prepare a compact of graphite powder mixed with binders. Resistivity of the impregnated compact was observed as heat treatment temperature was increased. It was observed that pore sizes of the GCTP samples increased as the heat treatment temperature increased. There was not a great difference between the flexural strengths of GCTP-IM and CPR-IM as the heat treatment temperature was increased. The resistivity of GPR700-IM, heat treated at 700℃ using phenolic resin as a binder, was 4829 μΩ·cm which was best value in this study. In addition, it is expected that with the appropriate selection of carbon powder and further optimization of process we can produce a composite bipolar plate which has excellent properties.

PURPOSES : The objectives of this study are to develop the eco-friendly pavement material using polyurethane binder and evaluate mechanical properties of the developed binder and concrete. METHODS : The bending beam test was conducted to select the sample candidates of polyurethane binder based on the bending strength. The characteristics of viscosity, curing time, and temperature change of sample binder was examined on different temperature conditions. The mechanical properties of polyurethane binder was estimated using the dynamic modulus testing. The indirect tensile strength test was conducted on polyurethane binder concrete with different gradation and binder content for evaluating the mechanical properties of concretes. RESULTS : Based on the beading beam test, four different binder samples were prepared for estimate the mechanical properties. The viscosity of polyurethane binder tends to increase with increase of liquid temperature and the hardening phenomenon begins 10 to 15 minutes at room temperature after mixing the resin and hardener. It is observed that the dynamic modulus of binder increases as loading frequency increases and change of modulus is found to be the highest in the PU-2I binder type. The PU-2I binder concretes shows the largest value of indirect tensile strength and indirect tensile energy. CONCLUSIONS : The use of polyurethane binder as pavement materials is capable of increasing the pavement performance and reducing the detrimental environmental effect during the highway construction.

PURPOSES: In this study, various laboratory tests were performed to investigate the suitability of wasted vinyl as a modifier of asphalt binder. METHODS: Based on the ASTM specification, variations in material properties of asphalt binder such as penetration, flash point, softening point, ductility, penetration index (PI), and performance grade (PG) with vinyl content were tested and analyzed. RESULTS: Lavoratory tests revealed that penetration and ductility of the asphalt binder increased with the vinyl content. The flash point, softening point, and PI decreased, and PG changed from 64-22 to 70-22 with increase of the vinyl content. CONCLUSIONS: Wasted vinyl modified the material properties of the asphalt binder. However, the asphalt binder with vinyl content over 6.0% was unsuitable as a pavement material.

PURPOSES: SUPERPAVE binder grade tests including Multiple Stress Creep and Recovery(MSCR) test are applied to evaluate rheological properties of four polymer modified binders. METHODS: To evaluate grade of four modified binders, PG testing protocols, such as DSR, BBR and MSCR are employed. RESULTS: It is observed that MSCR test shows different performance grades especially on modified binders. Both DMP and EG binder show similar high temperature performance to SBS 5% modified binder. CONCLUSIONS: Binder Grading system in Korea need to be reviewed to properly reflect the performnace of modified binders. The binders modified with DMP and EG can be possible alternatives SBS 5% modified binder considering its performance and cost.

PURPOSES : This study deals with the working life of polymer concrete, which is typically used as a repair or overlay material for portland cement concrete pavements. METHODS : In the scope of this study, laboratory testing was conducted on fresh MMA modified UP polymer concrete, which uses an MMA monomer for viscosity adjustment and strength improvement of UP resin. The experimental variables were temperature (-20 to +20℃) and binder components (MMA, MEKPO, and DMA). RESULTS : The result showed that the optimum binder ratios for polymer concrete production were 12, 11, and 10 wt.% when the MMA contents were 20, 30, and 40 wt.%, respectively. The working life of polymer concrete depending on temperature and binder components could be expressed by a logarithmic functional formula. The coefficient of variation for each binder component was the highest for DMA content while the lowest for MEKPO content. Also, the contents of each binder component for ensuring the working life of 60 minutes were proposed. CONCLUSIONS : Ultimately, the present study derived a linear regression equation estimating 60 minutes working life based on the setting times of each binder component.

We present the effect of a coupling agent on the optoelectrical properties of few-walled carbon nanotube (FWCNT)/epoxy resin hybrid films fabricated on glass substrates. The FWCNT/epoxy resin mixture solution was successfully prepared by the direct mixing of a HNO3-treated FWCNT solution and epoxy resin. FWCNT/binder hybrid films containing different amounts of the coupling agent were then fabricated on UV-ozone-treated glass substrates. To determine the critical binder content (Xc), the effects of varying the binder content in the FWCNT/silane hybrid films on their optoelectrical properties were investigated. In this system, the Xc value was approximately 75 wt%. It was found that above Xc, the coupling agent effectively decreased the sheet resistance of the films. From microscopy images, it was observed that by adding the coupling agent, more uniform FWCNT/binder films were formed.

본 연구의 목적은 중온화 첨가제(LEADCAP®)를 사용한 중온 아스팔트 바인더의 노화 방법에 따른 물성 변화 특성을 평가하고자 하였다. 아스팔트 바인더의 노화 거동을 모사하기 위해 단기노화인 RFTO를 실시하였으며, 햇빛에 의한 자연 노화 거동을 알아보기 위해 자외선 경화기를 이용하여 자외선에 의한 열화거동을 모사하였다. 이러한 열화 중온 아스팔트 바인더의 역학적인 물성과 유변동학적인 특성을 시험하기 위해서 만능시험기(UTM)과 동적전단유동기를 이용하여 직접인장력과 유변동학적인 거동을 평가하였다. 또한, 열분석 장비를 이용하여 온도에 따른 중온 아스팔트 바인더의 특성을 평가하여, 자외선 노출에 따른 열화가 발생하여도 온도에 따른 물성 변화가 많이 발생하지 않음을 발견하였다. 70℃에서 중온화 첨가제가 첨가한 단기노화 중온 아스팔트 바인더의 경우, PG 등급에서의 고온 등급의 기준값을 만족함을 알 수 있었다. 또한 저온에서 중온 아스팔트 바인더의 인장 특성을 평가한 결과, 인장강도 향상과 함께 인장력이 증가됨을 알 수 있었다.

This study is to develop a ring binder which deals with punching process and ring pressing process consecutively for twin ring binding. The purpose of this study is to develop a vertical ring binder which operates punching and binding process in unification by using a power source. It is expected to reduce the personnel expenses more than 40% by uniting the two ring binding processes, which are imported products, into this trial manufacture. It is also expected to decrease the diversion of foreign currency by substituting imported electric ring binder, which costs almost 10 billion won in a year, to this binder.

본 연구는 배수성 아스팔트 포장에 사용하기 위하여 국내에서 개발한 개질 아스팔트 바인더 및 혼합물의 실내 및 현장 공용성을 평가한 연구이다. 국내에서 개발된 개질 아스팔트 2종에 대한 DSR, BBR 및 다양한 바인더 시험을 실시하여 공용성능이 상대적으로 우수한 1종의 개질 아스팔트를 선정하였다. 선정된 개질 아스팔트와 기존에 일본에서 사용되는 개질 아스팔트를 사용하여 각각에 대하여 배합설계를 실시하고, 배수성 아스팔트 혼합물을 생산하여 실내 공용성을 비교하기 위해 휠트래킹 시험, 수분손상 시험, 피로시험 등을 수행하였다. 그 결과, 공용특성 측면에서 국산의 개질 아스팔트가 일본 개질 아스팔트와 비슷하거나 경우에 따라서는 우수함을 확인하였다. 실내시험결과를 바탕으로 현장 시험시공을 실시하였고, 추적조사를 통하여 시간에 따른 공극률과 소음특성의 변화를 측정하였다. 그 결과 시공 초기에는 배수 및 소음 저감 능력이 우수하였으나 2년이 경과한 후 소음 저감 능력이 감소하여 SMA 포장과 비슷한 수준의 소음저감효과를 나타내었다.

상대적으로 강성이 큰 바인더가 높은 소성변형 저항력과 인장강도를 보이므로 바인더 강성이 아스팔트 혼합물의 러팅과 인장강도에 대해 중요한 인자라 할 수 있다. 혼합물의 인장 특성은 25℃에서 간접인장강도(ITS) 시험으로, 그리고 소성변형 저항성은 가장 보편적으로 60℃에서 반복주행(WT) 시험에 의해 측정된다. 변형강도(SD)는 60℃에서 아스팔트 콘크리트의 소성변형 저항성 추정을 위해 새롭게 개발된 특성이다. ITS와 SD는 정적재하 시험에 의해 측정되어 매우 간단하지만, WT는 상대적으로 긴 시간과 노력을 필요로 하는 반복 하중에 의해 얻어진다. 이 3가지 특성은 모두 바인더 강성에 의존하기 때문에, 한가지로부터 다른 하나의 특성을 추정하는 것이 가능할 것이다. 본 연구는 ITS 또는 SD시험에 의한 WT 소성변형 특성, 그리고 SD에 의한 ITS 추정의 가능성을 조사하였다. ITS에 의한 WT 추정결과 R2≒0.6으로 ITS가 높으면 WT 침하깊이가 낮은 경향을 보이는 것으로 관찰됐다. SD에 의한 ITS 추정은 R2≒0.64를, SD에 의한 WT 추정은 R2≒0.84를 보여 3가지 중에서 가장 높은 상관관계를 나타내었다. 결론적으로 SD에 의한 소성변형 저항성 추정 가능성이 상대적으로 높으며, 비록 R2이 다소 낮기는 하지만 WT와 ITS 결과 간에도 어느 정도의 상관성이 있다.