Laboratory evaluation of loading frequency effects on HMA self-healing

Self-healing is an intrinsic property of bituminous materials with a significant effect on the performance and durability of asphalt mixtures. Also, research has shown that the self-healing phenomenon affects the fatigue endurance limit of asphalt mixtures. In order to determine the fatigue endurance limit in the laboratory, the four-point bending (4PB) beam test is conducted at low strain levels. The 4 PB beam fatigue test at low strain amplitudes is time-consuming because of the self-healing phenomenon. In this study, to determine self-healing effects on the laboratory fatigue life of HMA, the 4 PB fatigue test loading frequency was increased from 10 Hz to 25 Hz. Analysis of results showed that the effect of self-healing on fatigue life can be approximately specified. Based on the results, self-healing factors range from 2.51 to 9.45 and increase by decreasing the 4 PB fatigue test strain level.