• Title/Summary/Keyword: asphalt mixtures

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Performance Evaluation of the High Durability Asphalt Mixture for Bridge Deck Pavements (고내구성 교면포장 아스팔트 혼합물의 공용성 평가에 관한 연구)

  • Park, Hee-Mun;Choi, Ji-Young;Lee, Hyun-Jong;Hwang, Eui-Yoon
    • 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.

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Correlation Analysis between Rut Resistance and Deformation Strength for Superpave Mixtures (수퍼페이브 혼합물의 소신변형저항성과 변형강도와의 상관성분석)

  • Kim, K.W.;Kim, S.T.;Kwon, O.S.;Doh, Y.S.
    • International Journal of Highway Engineering
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    • v.6 no.4 s.22
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    • pp.45-53
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    • 2004
  • This study dealt with correlation analysis between deformation strength and rut resistance of asphalt concretes based on binder grade in Superpave specification with changing submerging time. Currently, Mashall mix design is known to have little correlation with rutting related performance. Therefore, some agencies started to use the Superpave method for asphalt mix design. But this method has a weak point in that it can not distinct mechanical property of the asphalt mixtures designed. For solution of these problem, this study used deformation strength, $S_D$, of Kim test which is a new approach under development for finding property which represents rut resistance characteristics of asphalt mixtures under static loading. This study used two aggregates from two regions and five PG asphalt binders. Final rut depth (DR) and dynamic stability (DS) from wheel tracking (WT) test were obtained. and $S_D$ value of the same mixture specimen which was made by gyratory compactor was obtained using loading head [4(1.0)]. Three submerging times 30min, 40min, 50min were used as a test variable at $60^{\circ}C$. Correlation analysis of DR and DS with $S_D$ were performed based on PG grade. It was found out that the $S_D$ has a high correlation with DR and DS of superpave mixtures. The highest $R^2$ was found from the $S_D$ values of 30min. submerged specimen.

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Characteristics of Fatigue Resistance of Recycled Asphalt Concretes by Modified Mixing Process (재생 아스팔트 콘크리트 혼합물의 혼합방법 개선에 따른 피로저항 특성)

  • Doh, Young-Soo;Ko, Tae-Young;Kim, Kwang-Woo
    • International Journal of Highway Engineering
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    • v.8 no.4 s.30
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    • pp.135-143
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    • 2006
  • This study evaluated the fatigue resistance characteristics of hot-mix recycled asphalt mixtures which were prepared by a new blending method. Since the binder of RAP shows higher viscosity without being rejuvenated in the ordinary recycled mixture, this new(modified) blending method was developed for obtaining more uniform level of binder viscosity in the recycled mixture. Cold-planned RAP was collected and mix design was performed using 15% RAP content for two virgin aggregate, gneiss and granite. Penetration grade of 60-80 asphalt was used in mixing recycled mixture together with a polymer modifier, LDPE. Indirect tensile fatigue tests were carried out to evaluate characteristics of fatigue resistance of performance of recycled asphalt mixtures. The recycled mixtures with LDPE 6% showed higher repeated loading fatigue life. Fatigue life ratio of new(N) mixing method mixtures was approximately 0.6-0.7 before aging and 0.8-1.0 after aging treatment of ordinary(O) mixing method mixture. This means the N mixture becomes stronger with aging process increase. If further aging is treated, N mixture may be showing stronger resistance than O mixture.

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