Fatigue damage and self-healing behaviour of FMA-13 mixtures with varying asphalt content: experimental and numerical analysis

To investigate the fatigue mechanism and self-healing characteristics of FMA-13 mixtures designed with a wide-range asphalt content and their fatigue performance was evaluated through four-point bending tests. Finite element simulations using Abaqus were conducted to analyse the fatigue mechanism from a meso-structural perspective. The self-healing performance was further investigated through intermittent fatigue tests under various loading conditions. The results indicate that the fatigue life of FMA-13 mixtures increases with the asphalt-aggregate ratio. At 10 Hz, 15 °C and 600 με, the fatigue life of FMA-13(9.0) reaches 9.72 times that of AC-13. Finite element analysis reveals that during the moulding process of FMA-13, the fluid asphalt mastic adequately, filling the voids in the aggregate, substantially reducing the internal air voids and thereby minimising potential sites for early damage initiation. The self-healing test results demonstrate the improved healing capability in FMA-13 mixtures. Under intermittent loading at 15 °C with an hour rest period, 10 Hz and 600 με, the third fatigue life of AC-13 recovers only 6.4% of its initial value, whereas FMA-13(7.0) achieves a recovery of 79.5%. This indicates that FMA-13 mixtures are capable of efficient self-healing within a short period at room temperature compared to conventional AC-13.