The Application of Recycled Aggregates of Construction Debris in Asphalt Concrete Mix Design

The purpose of this research was to evaluate the application of recycled aggregates of construction debris such as concrete, cement block and rubbles from Pars-Kangan site in asphalt concrete mix design. To evaluate the performance of aggregates different mix designs with recycled aggregate percentages of 0, 10, 30, 50 and bitumen percentages of 4, 4.5, 5, 5.5, 6, and 6.5 were provided and two Marshall specimens (Totally 48 specimens) prepared for each mix design. Marshall test was conducted on the specimens to evaluate their physical and mechanical properties. The test results indicated that the increase of recycled aggregates percentage in asphalt concrete mix design leads to lower strength in Marshall specimens. Hence, in the next round of research the same asphalt concrete mix designs with bitumen-sulfur proportion of 60-40 were provided in order to increase the strength of aggregates. The Marshall physical and mechanical test results specified that sulfur has a significant role in increasing the strength of specimens. But increasing the recycled aggregates resulted in decrease of strength. By comparing the test results, it was inferable that sulfur doesn’t have a significant role in increasing the technical specifications of aggregates, and it only increases the strength of specimens.