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        검색결과 184

        41.
        2018.05 구독 인증기관·개인회원 무료
        Generally, asphalt binder experiences short-term aging during mixing and constructing processes in high temperature environments and long-term aging during the service life after opening the road. Binder aging inside asphalt mixtures incurs changes in strength of asphalt paved roads, which then changes physical properties of the mixture such as cracks and rutting resistance. This study aims to measure bond strength of aging asphalt binder using asphalt bond strength (ABS) test that can measure a bonding force of asphalt binder and aggregate surface using Pneumatic Adhesion Tensile Testing Instrument (PATTI) used previously in the paint industry as a testing method specified in AASHTO TP-91.
        42.
        2018.05 구독 인증기관·개인회원 무료
        The main objective of this research study is the performance evaluation of 40/50 and 60/70 binder for asphalt mixtures in Vietnam. To accomplish the objective of this research, a dense gradation with nominal maximum aggregate size of 19.0mm is used for the asphalt mixtures. Marshall Stability (MS) test, Tensile Strength Ratio (TSR) test, Wheel Tracking (WT) test, and Dynamic modulus test are conducted to evaluate the rutting and cracking performance of 40/50 and 60/70 binder in asphalt mixtures. It was found that the Marshall stability of asphalt mixtures using 40/50 binder is about 12% higher than asphalt mixtures using 60/70 binder while the rutting resistance of the mixtures with 40/50 binder shows 2.5 times higher than 60/70 binder at 15,000 load cycles. Moreover, the TSR of asphalt concrete using 40/50 binder and 60/70 binder are approximately 95% and 79%, respectively which means that using 40/50 binder is very good for moisture damage resistance. Finally, the dynamic modulus test was done at a reference temperature of 20oC and frequency of 1,0Hz. The dynamic modulus of asphalt mixture with 40/50 binder is about 6257 MPa, which is two times higher than asphalt mixture using 60/70 binder. Based on the results of this study, it can be concluded that asphalt mixtures using 40/50 binder can improve the rutting and moisture damage resistance of asphalt concrete under high temperatures and moisture conditions significantly. It is noted that these conclusions were based on only on a limited number of samples and conditions. Further studies must be conducted to investigate the effect of 40/50 binder on fatigue cracking of asphalt pavement in the field.
        43.
        2018.05 구독 인증기관·개인회원 무료
        When there is a significant stripping in asphalt pavement, it is common practice to use a hydrated lime (HL) as an anti-stripping additive (ASA). However, since many asphalt plants do not have facilities for weighing and casting HL, they prefer to use of a liquid-type ASA (LA). Therefore, various brands of LAs which show proper anti-stripping function are currently developed, imported, and marketed in Korea. In addition to the anti-stripping effect, the HL has been known to give a significant age-retarding effect on paved asphalt in the field. Therefore, there was a question about whether or not the LA provides the same anti-aging effect as The HL. This study investigated anti-aging effect of the asphalt mixes which were prepared using both ASAs and short-term aged and long-term aged in the laboratory. The absolute viscosity was measured as an aging index from the binder recovered from the mixes after short-term aging (STA) and long-term aging (LTA) processes. The results showed that there was a significant higher aging found from the LA-added mix than the normal mix without any ASA. On the other hands, the mix with HL showed significantly lower ageing level than the LA-added mix and normal mix. The retardation of age-hardening by using HL was more effectively observed when the STA condition was stronger.
        44.
        2018.05 구독 인증기관·개인회원 무료
        If asphalt-aggregate mixture is produced at a high temperature, the mixture will suffer a significant higher shortterm aging (STA) due to the elevated temperature. The binder in that mixture will be oxidized (aged) more than expected during STA due to the highly elevated temperature. The STA at the high-temperature level is one of the reasons why the hot-mix asphalt (HMA) mixture shows many distresses in the early stage of service life. In this respect, adopting warm-mix asphalt (WMA) technology is another advantage in the asphalt pavement industry. In this study, various levels of STA were used to evaluate aging levels of the binder in the mixture before and after STA. A gel-permeation chromatography (GPC) test was performed on the mixture particles without binder recovery to estimate the significance of aging for each case of STA. Statistical analyses were carried out to determine the difference in aging levels among STA temperatures. Statistical test results found that the aging level of the binder after STA was significantly higher than that of binders before STA at an α = 0.05 level. It was also found that the aging level of binders in the WMA mixture was significantly lower than that of binders in HMA after STA at an α = 0.05 level. It was observed that if an HMA mixture was produced at high-temperature STA, its aging level was estimated to be approximately four years in service.
        45.
        2018.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Active clay, bentonite and zeolite were used as porous materials for humidity controlling ceramic boards. The specific area and the pore volume of active clay were higher than bentonite and zeolite. The flexible strength of the gypsum board decreased with an increasing amount of porous material, and the flexible strength was lowest when active clay with a higher specific surface area than others porous materials was added. The specific surface area and total pore volume of ceramic boards containing porous material were highest at 102.25 m2/g, 0.142 cm3/g, respectively, when the active clay was added. In addition, as the amount of added porous materials increased, the specific surface area and total pore volume of the ceramic board increased, but the average pore diameter decreased. The addition of s porous materials with a high specific area and a large pore volume improved the moisture absorptive and desorptive performance of the ceramic board. Therefore, in this experiment, the moisture absorptive and desorptive properties were the best when active clay was added. Furthermore, as the amount of added porous materials increased, the moisture absorptive and desorptive properties improved. When 70 mass% of active clay was added to α-type gypsum, the hygroscopicity was the highest, about 300 g/m2, in this experiment.
        4,000원
        47.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : It is necessary to clarify the rheological properties of cement paste as a basic research in the development of mechanistic concrete mix design. The rheological properties of cement paste with different binder types, mix propositions, and with/without high range water reducers have been analyzed. METHODS: In this study, ordinary Portland cement, fly-ash, blast furnace slag, silica fume, and limestone powder were used as binders. The range of water-binder ratio was 0.3-0.5, and a total of 30 different mixes have been tested. The slump flow test, V-funnel test, and Dynamic Shear Rheometer (DSR) test were performed to analyze the rheological properties of cement paste. RESULTS : As a result of the slump flow test, it was found that the composition ratio of the binder contents greatly affected the paste flow when the high range water reducers were added. The results of V-funnel test showed that when the water-binder ratio was decreased without high range water reducers, the binder composition ratio had a large effect on the passing time of the V-funnel tester, but with high range water reducers the impact of the binder composition ratio was decreased. The slump flow and V-funnel have a certain relationship with the rheological factors (yield stress and plastic viscosity), but the correlation was not significant. Finally, we proposed the M-value considering the density and specific surface area of the binder. The correlation between rheological factors and M-value were better demonstrated than experimental values, but there is still a limit to predict the rheological factor in general mix design. CONCLUSIONS: In this study, the rheological properties of cement paste were analyzed. The binder type, composition ratio of binder, and with/without high range water reducers have combined to provide the complex effects on the rheological properties of cement paste. The correlation between the proposed M-value and rheological factor was found to be better than experimental results, but needs to be improved in the future.
        4,300원
        48.
        2017.04 구독 인증기관·개인회원 무료
        Sewerage age more rapidly than other facilities, leading to the destruction of the pipeline. Therefore, the replacement of old sewer pipes through long-term construction is costly. In order to solve this problem, this study investigated the ferronickel based sewer pipe with improved chemichal resistance and durability from concrete rigidity pipe. ABAQUS was used as the finite element analysis program and the load was calculated by the method given in the sewage facility standard. Therefore, the results of this study can be referenced in the design and construction of sewer pipes.
        49.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS: CRMA binders were produced using open blade mixers at 177℃ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS: The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.
        4,000원
        50.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study aims to show the difference of the binder aging level in the hot-mix asphalt (HMA) mixture after short-term aging (SA) under different aging conditions, such as mixture temperature and duration in hour. METHODS: Three SA times (i.e., 1 h, 2 h, and 4 h) at two temperatures (i.e., 160℃ and 180℃) were used for the normal mixtures prepared using a PG64-22 asphalt. The field long-term aging (LA) was simulated by applying the same LA procedure (65 h at 110℃) to all compacted specimens, prepared at the air void of 7% using each SA-treated mixture, in a convection oven. The binder aging level was measured in terms of large molecular size by gel-permeation chromatography (GPC) from the mixture and the absolute viscosity (AV) from the recovered binder. The aging levels were evaluated using those two properties after SA and LA, and then compared based on the normal SA (NSA) mixture (1 h at 160℃). The service life reduction caused by SA in various conditions was estimated based on the aging level of the field cores from different locations in various service lives. RESULTS: The results of the laboratory evaluation indicated that the binder of the mixture, which was treated at longer SA time and higher temperature, showed a significantly higher aging level than the NSA mixture. The binder aging level from a longer time, such as 2 h and 4 h SA, or at a higher temperature (180℃), were estimated to be similar to that of the mixtures, which had already been in field service for several years. CONCLUSIONS : The HMA mixture should be produced at a moderate temperature, such as 160℃, and placed within a limited hauling and queuing time to avoid a significant short-term aging of the binder before placement in the field pavement. The SA for a longer time at a higher temperature than the NSA condition was found to be detrimental to the service life of the asphalt pavement.
        4,000원
        51.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The performance properties (indirect tensile strength, rutting resistance, and resilient modulus) of recycled aged CRM mixtures and their correlation with Superpave binder properties (viscosity, high failure temperature, G*sinδ, and stiffness) were investigated. METHODS: A series of Superpave binder tests was performed by using a rotational viscometer, DSR, and BBR to evaluate the performance properties. In addition, the CRM mixes were artificially aged through accelerated aging processes, and their properties were evaluated. The correlation between the properties of recycled aged CRM binders and the engineering properties of recycled aged CRM mixtures was experimentally determined. RESULTS : The rut depth values decreased and the ITS values increased with increasing high failure temperature. In general, the resilient modulus properties seemed to be poorly correlated with the high-temperature values, regardless of the aggregate source. CONCLUSIONS: The recycled aged CRM binders and mixtures can lead to satisfactory performance, and the properties of these binders are strongly correlated with the engineering properties of the mixtures.
        4,000원
        52.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the fabrication of the Si negative electrode in Li-ion batteries (LIBs) containing the cross-linking polymer binder, in this work, the urethane acrylate (UA) oligomer was synthesized via a simple synthetic process. The cross-linked poly(urethane acrylate) (CPUA)/carbone black (CB)/Si composite (CPUA/CB/Si composite) was fabricated through reactions between their reactive vinyl segments in the UA oligomer. Interestingly, the CPUA/CB/Si composite showed better cycle performance than the poly(vinylidene fluoride) (PVdF)/CB/Si composite (PVdF/CB/Si composite) and the polyurethane (PU)/CB/Si composite (PU/CB/Si composite). The CPUA/CB/Si composite had the best lithiation of about 2586 mAh g-1. The UA oligomer showed a good compatibility with the electrode materials and current collector after and before a curing process.
        4,000원
        53.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study intends to develop an inorganic soil pavement material using industrial by-products and to evaluate its applicability as a road pavement material. METHODS: In this study, a compressive strength experiment was conducted based on the NaOH solution molarity and water glass content to understand the strength properties of the soil pavement material according to the mixing ratio of alkali activator. In addition, the strength characteristic of the inorganic soil pavement material was analyzed based on the binder content. The performance of the soil pavement was evaluated by conducing an accelerated pavement test and a falling weight deflectometer (FWD) test. RESULTS: As a result of the soil pavement material test based on the mixture ratio of alkali activator, it was identified that the activator that mixed a 10 M NaOH solution to water glass in a 5:5 ratio is appropriate. As a result of the inorganic soil pavement materials test based on the binder content, the strength development increased sharply when the amount of added binder was over 300 kg; this level of binder content satisfied 28 days of 18 MPa of compression strength, which is the standard for existing soil pavement design. According to the measured results of the FWD test, the dynamic k-value did not show a significant difference before or after the accelerated pavement testing. Furthermore, the effective modulus decreased by approximately 50%, compared with the initial effective modulus for pedestrian pavement. CONCLUSIONS: Based on these results, inorganic soil pavement can be applied by changing the mixture proportions according to the use of the pavement, and can be utilized as road pavement from light load roads to access roads.
        4,000원
        54.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present work reports a systematic study of using carboxymethylated cellulose (CMC) as water-bornebinder to produce Li4Ti5O12-based anodes for manufacture of high rate performance lithium ion batteries. When theLTO-to-CB-to-CMC mass ratio is carefully optimized to be 8:1:0.57, the special capacity of the resulting electrodes is144 mAh·g−1 at 10 C and their capacity retention was 97.7% after 1000 cycles at 1C and 98.5% after 500 cycles at5C, respectively. This rate performance is comparable or even better than that of the electrolytes produced using con-ventional, organic, polyvinylidene fluoride binder.
        4,000원
        55.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to develop new pothole repair materials using polyurethane-modified asphalt binder, and to evaluate them relative to current pothole repair materials in order to improve the performance of repaired asphalt pavement. METHODS : In the laboratory, polyurethane-modified asphalt binder is developed, and then asphalt binder is added to produce pothole repair materials. In order to evaluate the properties of this new pothole repair material, both an indirect tension strength test and a direct tension strength test are performed to measure the material strength and bond strength, respectively. Additionally, the basic material properties are evaluated using the asphalt cold mix manual. The strength characteristics based on curing times are evaluated using a total of 7 types of materials (3 types of current materials, 2 types of new materials, and 2 types of moisture conditioned new materials). The indirect tension strength tests are conducted at 1, 2, 4, 8, 16, and 32 days of curing time. The bond strength between current HMA(Hot Mix Asphalt) and the new materials is evaluated by the direct tension strength test. RESULTS AND CONCLUSIONS : Overall, the new materials show better properties than current materials. Based on the test results, the new materials demonstrate less susceptibility to moisture, faster curing times, and an improved bond strength between HMA and the new materials. Therefore, the use of the new materials reported in this study may lead to enhanced performance of repairs made to asphalt pavement potholes.
        4,000원
        56.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of particle size of Li-Si alloy and LiCl-KCl addition as a binder phase for raw material of anode were investigated on the formability of the thermal battery anode. The formability was evaluated with respect to filling density, tap density, compaction density, spring-back and compressive strength. With increasing particle size of Li-Si alloy powder, densities increased while spring-back and compressive strength decreased. Since the small spring-back is beneficial to avoiding breakage of pressed compacts, larger particles might be more suitable for anode forming. The increasing amount of LiCl-KCl binder phase contributed to reducing spring-back, improving the formability of anode powder too. The control of particle size also seems to be helpful to get double pressed pellets, which consisted of two layer of anode and electrolyte.
        4,000원
        57.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Translucent alumina is a potential candidate for high temperature application as a replacement of the glassor polymer. Recently, due to the increasing demand of high power light emitting diode (LED), there is a growing inter-est in the translucent alumina. Since the translucent property is very sensitive to the internal defect, such as voids insideor abnormal grain growth of sintered alumina, it is important to fabricate the defect-free product through the fabricationprocess. Powder injection molding (PIM) has been commonly applied for the fabrication of complex shaped products.Among the many parameters of PIM, the flowability of powder/binder mixture becomes more significant especially forthe shape of the cavity with thin thickness. Two different positions of the gate were applied during PIM using the disctype of die. The binder was removed by solvent extraction method and the brown compact was sintered at 1750oC for3 hours in a vacuum. The flowability was also simulated using moldflow (MPI 6.0) with two different types of gate.The effect of the flowability of powder/binder mixture on the microstructure of the sintered specimen was studied withthe analysis of the simulation result.
        4,000원
        58.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
        59.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
        60.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
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