Laboratory Investigation of SMA Mixtures Containing Date Palm Fiber, Cigarette Butts and Different Percentages of Reclaimed Asphalt Pavement

Stone matrix asphalt (SMA) is a gap-graded mixture that contains high percentages of coarse aggregates, bitumen, and filler. In the SMA mixture, due to the high amount of bitumen and the necessity to prevent it from draining down during asphalt transportation, bitumen adsorbent material is needed, which also has a stabilizing role. In this research, date palm fibers, cigarette butts, and Topcel (common cellulose fibers) were used. To reduce costs and protect the environment, reclaimed asphalt pavement (RAP) was used to produce SMA mixtures. This study aimed to investigate the effect of date palm fibers as natural waste fibers and cigarette butts as environmental pollutants and different percentages (w/w) of RAP in the SMA mixture. For this purpose, the draindown characteristics, moisture sensitivity, and rutting of SMA mixtures prepared with these materials were investigated using draindown basket, indirect tensile strength, and Hamburg wheel track tests. Results showed that in the draindown test, asphalt mixtures containing cigarette butts showed better performance than mixtures containing the other two fibers. Results of indirect tensile and rutting tests showed that by increasing the percentage of RAP, the indirect tensile strength increased and the rut depth decreased. Moisture sensitivity of samples containing 15% RAP and palm fiber was lower than the other mixtures. Although samples containing Topcel fibers performed better in rutting, the performance of samples containing date palm and cigarette butts fibers was also acceptable. Results showed that the date palm and cigarette butts with the application of RAP materials could contribute to the performance properties of SMA mixtures. These fibers can be suitable replacements for expensive fibers such as Topcel, and in addition to using RAP in the mix, they can provide a resistant and durable mixture.