• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.1-9
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• 2005

This is a basic research for producing hot-mix recycled asphalt mixtures and suggesting methods for solving quality problems, if any. Various mixing methods are introduced to mate aging evenly between old and virgin aggregates and to improve aging conditions. Gel-permeation chromatography(GPC) analysis was performed to evaluate aging of binders coated on coarse aggregates and a matrix separately. Round-shaped aggregates(13m gravel) were used in manufacturing mixtures for analysis of aging levels in recycled mixtures. It was found out that there was significant difference in aging levels between the binder coated on RAP's coarse aggregates and on virgin aggregates in a recycled mixture. The difference in the aging level was reduced by modifying mixing method(RAP and virgin binders were mixed first and then virgin aggregates were introduced). Among A to E mixing methods studied, the D was turned out to be the best.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.11-20
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• 2005

This study examined the correlation between mechanical properties and LMS(Large molecular size) of binders in hot-recycled asphalt mixtures. Hot-recycled asphalt mixtures were manufactured by various mixing methods. Laboratory tests including indirect tensile strength, wheel tracking test and Kim test were performed for each recycled mixture. Gel-permeation chromatography (GPC) analysis was performed for the binders coated on virgin and old (RAP) aggregates separately. For the purpose of binder aging analysis, a round-shaped virgin coarse aggregates (13mm gravel) were introduced in recycled mixtures. This makes possible to distinguish the virgin aggregates from RAP aggregates in recycled mixtures for GPC sampling. Results of GPC showed that there was significant difference in aging level between the binder coated on RAP and that of virgin aggregates in the same recycled mixture. Regression analysis was performed to correlate mechanical properties to LMS ratio. Results showed that most of the mechanical properties had relatively good correlation with LMS. This trend agree with LMS increase up to some degree, but fails for further LMS increase.

• 한국도로학회:학술대회논문집
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• 2002.10a
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• pp.111-118
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• 2002

• 한국도로학회:학술대회논문집
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• 2004.10a
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• pp.155-162
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• 2004

• 한국도로학회:학술대회논문집
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• 2004.10a
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• pp.131-136
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• 2004

• 한국도로학회:학술대회논문집
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• 2003.10a
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• pp.229-234
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• 2003

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.348-355
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• 2021

Asphalt, widely used for road pavement, has different required physical properties depending on the environment to which the road is exposed. Therefore, it is essential to maximize the life of asphalt roads by evaluating the physical properties of asphalt according to additives and selecting an appropriate formulation considering road traffic and climatic environment. Dynamic shear rheometer(DSR) test is mainly used to measure resistance to rutting among various physical properties of asphalt. However, the DSR test has limitations in that the results are different depending on the experimental setting and can only be measured within a specific temperature range. Therefore, in this study, to overcome the limitations of the DSR test, the rheological characteristics were predicted by learning the images collected from atomic force microscopy. Images and rheology properties were trained through EfficientNet, one of the deep learning architectures, and transfer learning was used to overcome the limitation of the deep learning model, which require many data. The trained model predicted the rheological properties of the asphalt binder with high accuracy even though different types of additives were used. In particular, it was possible to train faster than when transfer learning was not used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1043-1051
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• 2017

Asphalt overlay on deteriorated concrete pavement has a problem of early damage due to reflective cracking. There is a need for a new method capable of reducing reflection cracking and ensuring the durability of pavement. The purpose of this study was to obtain durability of asphalt overlay with stress absorbing membrane interlayer (SAMI) using epoxy asphalt binder. The tensile performance, durability, water resistance and bonding performance of Epoxy-SAMI were evaluated by various tests. As a result of tests, Epoxy-SAMI meets the quality standard of the bridge waterproofing material. The repeated direct tensile test was carried out to investigate the effect of reflective cracking reduction. When the Epoxy-SAMI was applied, it had 1.2~1.56 times higher reflective cracking resistance than PSMA asphalt concrete with the thickness of 10cm even if the section thickness decreased. 4-point bending beam test results showed the number of fatigue failures increased 7.5 times when Epoxy-SAMI was applied. The Epoxy-SAMI was found to be effective in improving the durability of the asphalt pavement overlay because it serves to prevent reflective cracking, increase lifespan, and function as a waterproof layer.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.51-62
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• 2007

Recently, the pavement distresses in the bridge deck have seriously affected the durability of bridge deck and driver's safety. The existing asphalt materials have the limitations in reducing the pavement distresses of brides deck. To protect the bridge deck and withstand the high deflection, it is necessary to develop the asphalt materials with good fatigue resistance for bridge deck pavement. The asphalt binder combined with SBS and two other admixtures has been developed for improving the resistance to fatigue cracking, productivity, and workability for bridge deck pavement. Based on the various binder test results, the developed binder is found to be PG 70-34 indicating very higher resistance against fatigue cracking. Fatigue testing, wheel tracking testing, and moisture susceptibility testing have been conducted to evaluate the performance of asphalt mixtures developed in this study. Laboratory test results show that the developed asphalt material has three times higher fatigue lives than the typical modified asphalt mixture. Full scale accelerated testing was also performed on the typical asphalt mixture and newly developed asphalt mixture to evaluate the full scale performance of asphalt mixtures. Test results indicate that the length of cracking on the new materials is only 38% of the typical material at the 250,000 load repetitions.

• 한국도로학회지:도로
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• v.11 no.2
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• pp.26-33
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• 2009

본 특집기사는 미국 NCAT(National Center for Asphalt Technology)에서 실험한 보고서(Hurley 및 Prowell, Evaluation of Sasobit for Use in Warm Asphalt, 2005)를 정리한 것으로 아스팔트 중온포장에 대해 연구하는 사람들에게 어느 정도 도움을 주고자 일부 내용을 번역하였다. 특히, 골재와 바인더 믹싱 및 현장다짐시 온도를 낮추어 궁극적으로 $CO_2$를 저감하고자 하는 노력이 많은 아스팔트 포장관련 종사자 및 연구자들에 의해 활발히 수행되고 있다. 본 기사에서는 중온에서도 작업성을 원활하게 하기 위해 사용되는 많은 첨가제 중 Fischer-Tropsch 왁스인 Sasobit에 대해 살펴보고자 한다. 여기서 관심을 두고자 하는 점은 중온 아스팔트를 실제로 활용할 시 과연 일반 아스팔트 포장과 비교했을 때 어느 정도의 공용성(Performance)을 확보할 수 있느냐 하는 점이다. NCAT의 실내실험을 통해 알아낸 결과로는 진동다짐기를 이용하는 것이 보다 현실적이라는 것과 중온다짐에 따른 아스팔트의 동탄성 계수의 변화가 적다는 것이다. 또한 APA(Asphalt Pavement Analyzer)를 통해 소형변형의 가능성이 높지 않음을 알 수 있었으며, 중온 아스팔트를 사용함에 따른 일반적인 문제점인 수분민감성이 커지는 현상에 대해서 실험을 통해 검증한 결과, 박리방지제를 쓰는 것이 좋다는 결론을 얻었다. 전반적으로 Sasobit의 실내공용성 평가는 우수하다고 보고되고 있다.