Calculation and evaluation of activation energy as a self-healing indication of asphalt mastic

• Healing function of asphalt materials based on Arrhenius law is developed. The standard test procedure to get activation energy is put forward.
• It proves that it is reasonable to adopt activation energy value as the indication to evaluate the self-healing ability of asphalt mastic.
• The effects of asphalt and filler, asphalt-filler ratio, damage degree on the activation energy and self-healing ability of asphalt mastic are discussed.

Self-healing, as a very valuable characteristic, should be considered when selecting and designing constitutions of asphalt materials. It is necessary to develop a fundamental and universal healing evaluation indication based on the healing mechanism. However, most existing healing evaluation indication lacks physical meaning and hardly can predict the time-dependent healing process under different conditions. In this paper, the formulation of activation energy as a self-healing indication is developed based on the Arrhenius law. The procedure to get the activation energy of different asphalt mastic is put forward. Nine samples of different asphalt mastic are prepared. Then, the fatigue–rest–fatigue tests are employed to get the activation energy of nine asphalt mastic. Finally, the potential of the activation energy as the healing evaluation index for asphalt mastic is studied, and the effect of type of asphalt and filler, asphalt-filler ratio, damage degree on the value of activation energy is discussed. It is found that the healing activation energy can obviously distinguish the healing ability of different asphalt mastic. Healing activation energy represents the minimum energy required for the time-dependent strength gain and reflects the time-dependent strength gain rate, also can rank the time-dependent healing capacity of different asphalt mastic.