Asphalt binders have been shown to undergo significant time-dependent stiffening when stored at low temperatures. This physical hardening has a significant effect on the laboratory performance of asphalt binders. However, the importance of isothermal conditioning for asphalt mixtures and its effect on thermal cracking performance have been a subject of significant debate. A theoretical approach accounting for the glass transition and physical hardening in the thermal stress buildup in mixtures was derived from relaxation modulus master curves, the William–Landel–Ferry equation, Boltzmann's superposition principle, and a model describing the isothermal contraction of asphalt as a continuous function of conditioning time and temperature. With the model predictions, it is shown that thermal stress relaxation and stress buildup induced by physical hardening can continuously affect thermal stress throughout the cooling process. The cooling rate also affected the amount of delayed stress buildup that occurred after the temperature had stabilized at isothermal conditions as a result of physical hardening. A relatively simple device was developed and used for verification and support of the thermal stress model. Mixture measurements performed at different cooling rates and isothermal conditions supported the theoretical predictions. The findings clearly show that the effect of physical hardening on stress buildup in mixtures is measurable and important. Therefore, the glass transition of asphalts and their behavior under isothermal conditioning needs to be measured to better predict thermal cracking.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Modeling Thermal Stress in Asphalt Mixtures Undergoing Glass Transition and Physical Hardening


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2012-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Glass Transition Behavior and Physical Hardening of Asphalt Binders

    Bahia, H. U. / Anderson, D. A. | British Library Online Contents | 1993



    Physical Hardening of Asphalt Binders Relative to Their Glass Transition Temperatures

    Anderson, David A. / Marasteanu, Mihai O. | Transportation Research Record | 1999


    Effects of Physical Hardening on Stress Relaxation in Asphalt Cements

    Evans, Michael / Marchildon, Ryan / Hesp, Simon A. M. | Transportation Research Record | 2011


    Low-Temperature Physical Hardening of Hot-Mix Asphalt

    Romero, Pedro / Youtcheff, Jack / Stuart, Kevin | Transportation Research Record | 1999