HOW TEMPERATURE AND LOADING RATE AFFECT THE YIELD BEHAVIOR IN POLYMER-MODIFIED ASPHALT SYSTEMS

In developing a comprehensive low-temperature binder specification method, it is necessary to understand the large strain yield behavior of the binder at low temperatures. In this study, the effect of loading rate and temperature on low-temperature yield properties were evaluated for two asphalts, one from the California Valley and one from Bow River, straight and modified with 5% by weight of four commercial polymers (styrene-butadiene diblock, triblock, and radial, and ethylene-vinyl acetate copolymers). The Bow River asphalt was also tested with the addition of mineral filler. Results showed that both the source of the bitumen as well as the nature of the additive and the presence of filler were found to have a significant influence on how the yield stress changes with temperature and loading time. Only one homogeneous, California Valley binder modified with styrene-butadiene-styrene copolymer, provided a typical Eyring plot with a constant activation energy of 42 kJ/mol and activation volume of 3.7nm3. Other systems showed atypical behavior in that the activation parameters changed rapidly with both temperature and rate of loading. The yield flow process appeared to consist of a number of different mechanisms such as viscous flow, microcracking and interfacial failure. The addition of polymers to asphalt generally increased the yield stress at low temperature, and the addition of filler increased the yield stress and reduced the activation volume for viscous flow. Directions for future research are discussed.

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  • Corporate Authors:

    Taylor & Francis

    4 Park Square, Milton Park
    Abingdon,   United Kingdom  OX14 4RN
  • Authors:
    • Hesp, SAM
    • Roy, S D
  • Publication Date: 2003-3

Language

  • English

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Filing Info

  • Accession Number: 00964769
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Oct 9 2003 12:00AM