Evaluating fatigue and crack resistance of asphalt mixture containing zinc tailing aggregates

Roads as one of the most important components of the transportation system involve a large quantity of construction aggregate. Limitation in natural-aggregates sources makes it necessary to use alternative materials as a substitute to natural-aggregates. To achieve this goal, the byproducts tailings of zinc soil separation and concentration process named zinc tailings were used as an aggregate in asphalt mixture. In this research study, the fatigue, low-temperature, and moisture susceptibility performance of fabricated asphalt mixtures using limestone, siliceous and tailing aggregates were investigated. For this purpose, the four-point bending beam (4PB),semicircular bending (SCB), and indirect tensile strength (ITS)tests were employed. Findings from 4PB tests indicate that asphalt mixture containing zinc tailings as aggregates have longer fatigue life than the mixture fabricated with limestone aggregates at the strain level of 600 microstrain. However, caution needs to be exercised at higher strain levels. Based on SCB test results, the fracture energy values for mixture with tailing aggregates were almost constant at temperatures of - 6, - 10, and - 12 degrees C while the results show fracture energy reduction for other mixtures at a lower temperature. Moreover, the cracking resistance index (CRI) indicates that the tailing aggregates fabricated mixture has acceptable low-temperature performance. Finally, the TSR values show that mixture containing zinc tailing aggregates are more resistant to moisture damage compared with siliceous fabricated mixture.