• Elastomers and Composites
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• 제57권4호
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• pp.215-221
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• 2022

In this study, high-penetration asphalt with low greenhouse gas emissions was used in the asphalt mixing process to reduce the carbon emissions during the reaction due to its capacity to be produced even at low temperatures. In effect, cationic, anionic, and non-ionic dispersants were added and mixed in different feeding ratios, seeking an effective dispersion of the modifiers (SIS, PS, TPEE, and SEBS) into the high-penetration asphalt matrix and forming an asphalt binder with a melting point of 120 ℃. The compatibility of the modifiers and the high-penetration asphalt was examined using SEM and DSC techniques, and the role of NDP-1 as a dispersant was carefully investigated with respect to dissolution time. The analyses showed that: (1) the dispersibility of the asphalt binder is good when the non-ionic dispersant is used; (2) as the concentration of the non-ionic dispersant increases, the dissolution time decreases and the domain size contracts; (3) the ND70-PS has the shortest dissolution time, the lowest agglomeration rate, and a single Tg value.

• Elastomers and Composites
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• 제32권3호
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• pp.166-172
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• 1997

The objective in this study was investigated temperature susceptibility and low temperature fracture of rubber modified asphalt. A chlorinated polyethylene elastomer, Tyrin CM0730, was added to 200/300 grade asphalt with 3.0 and 5.0wt% to improve campatibility. The elastomer modified asphalts were analyzed for temperature susceptibility relating to penetration index(PI) and penetration-viscosity number(PVN) as well as low temperature fracture relating to fracture energy $(G_{IC})$. These indices were obtained from the measurements of penetration, viscosity, failure load and modulus. The addition of small amounts of elastomer to the asphalt resulted in a significant increase of both the PI and PVN over an unmodified asphalt. Also, the fracture energy increased with the addition of elastomer to asphalt. These significant improvement at both the high and low temperature result in enhanced performance.

• 한국도로학회논문집
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• 제1권2호
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• pp.121-133
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• 1999

본 논문은 국내 정유사에서 생산되는 도로 포장용 아스팔트에 대하여 노화에 따른 거동 특성을 파악하였다. 이를 위해 국내의 5개 정유회사에 생산되는 두가지 등급의 아스팔트 제품(침입도 85-100, 침입도 60-70)을 포함한 총 9종에 대하여 노화 단계별(노화 이전, 단기노화, 장기노화)로 국내 스트레이트 아스팔트의 침입도$(25^{\circ}C)$, 점도$(50^{\circ}C\;135^{\circ}C)$, 연화점, 및 DSR 시험$(-20^{\circ}C\sim30^{\circ}C)$을 수행하여, 아스팔트의 물성 변화 특성을 고찰하였다. 연구 결과, 국내 스트레이트 아스팔트의 거동은 고온($60^{\circ}C$근방) 및 상온$(10-30^{\circ}C)$범위에서 정유사 제품에 따라 상당한 차이를 나타내었으며, 저온의 경우에는 정유사 제품이나 등급에 관계없이 거의 유사한 거동을 나타내었다. 따라서 어느 정유사의 아스팔트를 사용하는가에 따라, 저온에서의 온도 균열에 대한 저항성은 다소 비슷한 수준일 것으로 판단되지만, 소성변형 및 피로 균열에 대한 저항성이 상이하게 나타날 것으로 판단된다.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.690-697
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• 2017

본 연구에서는 방수시트재를 위한 아스팔트의 styrene-butadiene-styrene (SBS)와 styrene-isoprene-styrene (SIS)에 의한 개질에 있어서 자가치유성을 가지는 개질아스팔트 방수시트재의 연화점(softening point), 침입도(penetration), 저온굴곡저항성능(low temperature flexibility), 점도(viscosity) 및 부착성능(adhesion) 등의 물성을 관찰하고, 반응표면분석법(response surface methodology, RSM)을 활용하여 아스팔트 질량 대비 SBS와 SIS의 적정조성을 도출하고 자가치유성을 가지는 개질아스팔트 방수시트재의 물성을 최적화하였다. 고온에서 측정이 수행되는 연화점과 점도는 SBS 또는 SIS의 함량이 증가함에 따라서 유의하게 값이 증가하였다. 그러나 함량 대비 연화점과 점도 증가분은 SBS 경우가 SIS보다 커짐이 관찰되었다. 이러한 원인은 SBS와 SIS의 열적거동의 차이 때문인데, SBS는 고온에서 점도 상승을 동반하는 겔화(gelation)가 되어 가교도가 커지나 SIS는 점도감소를 초래하는 폴리이소프렌 블록의 사슬분리(chain scission) 때문에 사슬꼬임(chain entanglement)이 상대적으로 적어지기 때문이다. 반면에 SIS-SBS 개질아스팔트는 상온에서 측정되는 침입도, 부착성능 및 저온굴곡성능에 대하여, 아스팔트 63 g을 기본으로 SIS 4~5 g과 SBS 8.5 g의 조성에서 최소 탄성거동을 나타내어 최대 침입도 및 최대 부착성능과 최저 저온굴곡성능 값을 보였다.

• 한국도로학회논문집
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• 제15권4호
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• pp.85-94
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• 2013

PURPOSES: The performance of tack coat, commonly used for layer interface bonding, is affected by application rate and curing time. In this study, bonding strength tests were performed according to the application rate and curing time of asphalt emulsion. Based on finding from this study, optimum application rates and curing times are proposed. METHODS: In order to investigate bonding characteristic of asphalt emulsion, tests were performed on both asphalt concrete pavement and portland concrete pavement. Also, asphalt emulsions were tested at the application rate of 0, 0.2, 0.4, 0.6, and $0.8{\ell}/m^2$ and at the curing time of 0, 0.5, 1, 2, and 24 hours. Pull-off test and shear bonding strength test, which commonly used for bonding strength measurement of asphalt emulsion, were adopted for this study. To assess field performance under different testing condition, asphalt emulsions were applied to in-service pavement. Throughout coefficient of determination analysis between material index properties from asphalt emulsion and mechanical response from bonding strength tests, performance correlativity was analyzed. RESULTS: Test results show that optimum application rate for asphalt overlay on asphalt concrete pavement (AOA) and asphalt overlay on concrete pavement (AOC) was $0.4{\sim}0.5{\ell}/m^2$ and $0.3{\sim}0.5{\ell}/m^2$, respectively. According to the curing time increment, tensile strength and shear strength of AOC were increased to 22~44% and 20~39%, respectively. AOA case also show strength increment in tensile strength (42%) and shear strength (9%). We tested the applicability of tack coat materials at the field sites, and our findings demonstrated that the bonding (for D and E) and rapid curing (for B, C, and D, E) performances were superior than others. Among material index properties, there was a high correlation between penetration ratio and bonding strength test result. CONCLUSIONS : Result show that interlayer bonding strength was affected by asphalt emulsion type, application rate and curing time. AOC required slightly higher application ($0.1{\ell}/m^2$) than AOA. Both AOA and AOC cases show higher strength at longer curing time. Up to 2hours of curing, rapid strength increments were observed, but strength increment ratio was decreased after 2hours of curing. From the observed correlation between penetration ratio and bonding strength, it is expected that penetration ratio can be used as one of important factors affecting bonding strength analysis.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.82-88
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• 2012

재생아스팔트 포장은 환경과 경제성 측면에서 일석이조의 대안으로 인식되고 있습니다. 이런 효과를 얻기 위해서는 국내에서 이 분야에 필요한 기초적인 연구가 필요하다고 판단됩니다. 특히, 재생 첨가제는 재생아스팔트의 품질 향상에 가장 큰 효과를 얻을 수 있기 때문에 조속히 발전하고 연구되어야 할 분야입니다. 본 연구에서는 국내에서 시판되는 재생 첨가제에 대해서 물성 실험을 수행하였습니다. 인공 노화 아스팔트 시료에 첨가제를 혼합하여 침입도 실험결과 오일계 첨가제는 목표 침입도를 회복하였습니다. 같은 시료를 기존의 공용성 등급실험 방법으로 실험한 결과에 따르면 $G^*/sin{\delta}$ 값이 대폭 증가하여 기준을 매우 크게 상회하는 것으로 나타났으며, 피로시험에서는 노화바인더 수명과 근접한 결과를 보였습니다. 기존 공용성 등급의 소성변형 저항관련 시험인 MSCR 결과에서는 폴리머형 첨가제의 리커버리가 향상되는 것으로 나타났습니다.

• 대한화학회지
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• 제11권1호
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• pp.17-21
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• 1967

For utilization of Bunker-C residual oil produced at KOCO., the auther tested the properties of vacuum fraction and blown asphalt, and as the result of it, (1) Vacuum fraction had so broad range of viscosity and high flash point that could be produced all kind of lublicating oil, but had to be dewaxed for high pour point, (2) Urea dewaxing was suitable to lighter fraction but not to heavier fraction, so, for heavier fraction, solvent dewaxing was needed. (3) Blown asphalt produced from vacuum residue had uniform relation between softening point and penetration in spite of broad change of blowing condition and adding of catalyst.

• Geomechanics and Engineering
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• 제36권1호
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• pp.39-50
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• 2024

Bitumen and high-quality subangular aggregates, the two principal materials used for asphalt concrete construction, are finite and expensive materials. The general availability of crumb rubber and naturally occurring aggregates of different shapes, especially flat and elongated shapes, indicates that they are feasible alternative materials for expanding the volume of bitumen and utilizing a wider range of aggregate shapes for the development of asphalt concrete, with an associated environmental benefit. The study investigated the effect of adding up to 15% crumb rubber and aggregates sorted into different groups, i.e., rounded, elongated, flat, and their combinations, on the rheological and mechanical properties and durability of 50/70 of hot-mix asphalt pavement. The addition of crumb rubber decreased ductility and penetration but increased the softening point. For a 5.5% bitumen content, asphalt concrete briquettes consisting of 7% crumb rubber and three types of aggregate shapes, i.e., 100% rounded, a mix of 75% rounded and 25% elongated, and a mix of 75% rounded, 15% elongated and 10% flat, were associated with high Marshall stability and indirect tensile strength as well as low lateral deformation due to their high solidity and moderate angularity ratio. Also, the addition of 7% crumb rubber resulted in a significant improvement in the tensile strength ratio and rebound strain of briquettes consisting of 75% rounded and 25% elongated aggregates and those with 75% rounded, 15% elongated and 10% flat aggregates. In relation to the parameters investigated, the three groups of briquettes met some of the local (South Africa) requirements for the surface course and base course of low traffic volume roads.

• 한국도로학회논문집
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• 제17권2호
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• pp.39-46
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• 2015

PURPOSES: The objectives of this study were to develop a new polymer-modified emulsion for application to tack coats and to evaluate its properties by comparing it with other types of asphalt emulsions, with the goal of providing an enhanced tack coat material for use in construction. METHODS: Modified asphalt binders were developed from using SBS and SBR latex in the laboratory, and their fundamental properties, such as their penetration index and PG grade, were evaluated. Based on the properties, a new tack coat material was developed. To evaluate the newly developed asphalt emulsion, the bonding strength between the two layers of HMA was measured by applying a uniaxial tensile test and shear test. For the tests, a total of four different conditions were applied to the specimens, including the developed asphalt emulsion, latex modified asphalt emulsion, conventional asphalt emulsion, and non-tack coating. RESULTS AND CONCLUSIONS: Overall, the developed asphalt emulsion exhibits the best bonding strength behavior among all of the three types. Also, the two types of polymer-modified emulsions were found to be better for application for use as a tack coat than a conventional emulsion. Especially, at a high temperature ($50^{\circ}C$), the conventional asphalt emulsion no longer acts as a tack coating material. Therefore, the polymer-modified emulsion should be considered for application to tack coat construction during the summer.

• 한국철도학회논문집
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• 제18권3호
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• pp.252-260
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• 2015

아스팔트 노반상 자갈궤도(이하, AC자갈궤도)는 아스팔트 콘크리트 노반(이하, AC노반)에 의한 열차하중의 분산으로 노반 두께 감소 효과, 빗물의 침투방지 효과로 인한 노반부의 강도저하와 연약화 방지 효과, 노반 분니 방지 및 동상방지에 의한 유지보수비 절감 효과를 얻을 수 있다. 이와 같은 장점들에 의해 AC자갈궤도는 유럽 및 일본 등에서 널리 사용되고 있으며 국내에서도 도입을 위한 연구가 진행 중이다. 본 논문에서는 유한요소해석 프로그램인 ABAQUS을 이용하여 현재 철도설계기준에 제시되어 있는 고속철도용 자갈궤도의 성능에 부합하는 AC자갈궤도 단면을 선정하고 선정된 2개의 단면을 대상으로 실물 대형 정 동적 열차하중 재하 시험을 수행하였다. 실대형 실험 결과, AC자갈궤도가 강화노반 상면에 작용하는 토압이 상대적으로 작게 측정되었으며 탄성 및 소성변위도 상대적으로 유사 또는 작은 것을 알 수 있었다. 따라서 AC자갈궤도가 자갈궤도에 비해 열차하중 분산효과에 의한 강화노반 두께 감소효과가 있고 소성변위도 작으므로 궤도의 장기 유지관리 측면에서도 유리한 궤도구조임을 확인하였다.