Results of low-temperature testing of Bow River asphalt binders and concrete mixtures, unmodified and modified with three commercially used polymers [diblock styrene-butadiene (SB), radial styrene-butadiene-styrene (SBS), and ethylene-vinyl acetate], are discussed. Thermal stress-restrained specimen tests, at a cooling rate of 10°C/h, were used to evaluate the performance of binders and mixtures. Binders were restrained as direct tension specimens with and without a sharp starter crack. Notching of the samples resulted in lower failure loads for all systems. But three of the four binders failed at warmer temperatures. The fourth binder, an exceptionally tough radial SBS-modified system, remained unaffected in this regard. Changes in failure temperatures ranged from 0°C (radial SBS) to +12°C (diblock SB). A comparison of binder results with those obtained for the mixture yields additional insights. It appears that there are differences between binder and mixture failure modes. The higher stress levels encountered in the mixture give rise to energy dissipating mechanisms that do not occur at the lower stress levels in the binder test. It is unlikely that a specification based on binder failure stress or strain will predict performance in polymer-modified systems. Three-point bend tests on notched asphalt binder or mastic beams may provide more realistic conditions for measuring materials properties. A compression test on the binder or mastic may be used to determine additional important parameters, such as Young’s modulus and yield stress in compression, which along with the failure properties, will likely produce an improved fracture mechanics-based low-temperature failure criterion.


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    Titel :

    Low-Temperature Binder Specification Development: Thermal Stress Restrained Specimen Testing of Asphalt Binders and Mixtures


    Weitere Titelangaben:

    Transportation Research Record


    Beteiligte:


    Erscheinungsdatum :

    2001-01-01




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch