Crack Healing Potential of Asphalt Concrete Pavement

An asphalt pavement with self-repairing capabilities is believed to be very useful from the sustainable pavement point of view. This research focuses on understanding the self-healing mechanism of Asphalt concrete materials and the effects of material modifications, by means of testing. Two asphalt concrete mixtures were prepared, a fine blend and a coarse blend. Slab samples were prepared using roller compaction, beam specimens were obtained from slab samples for further testing. Tests were conducted at 20°C in an environmental chamber using hydraulic loading equipment. Strain controlled Repetitive loading test was applied using 0.1second have sine loads followed by 0.9 second of rest periods. Tests were performed to cause micro damage to the specimens, but the loads were stopped before macro cracking began. Damage accumulation was measured using the changes of stiffness and deformation. Crack healing rate was determined in terms of the recovered stiffness, deformation, and increment in fatigue life. Beam specimens were subjected to load repetitions at 20° C until 50% of the stiffness was retained, then beams were stored in an oven for two hours at 85° C, cooled to 20° C, then subjected to another cycles of load repetitions. Steric hardening appeared to play a significant role in a mixture’s response during the loading and healing portions of laboratory tests. Healing rate varied upon variation in gradation, type of modifier used, asphalt content, and the strain level adopted. Recovered stiffness and increment in fatigue life appear to be an adequate measure of healing.