Effect of Waste Cigarette Butt Fibers on the Properties and CO₂ Footprint of Bitumen

This research utilized recycled acetate fibers from discarded cigarette butts (CBs) as reinforcing materials, reducing solid waste and enhancing the properties of bitumen. The surface properties of the fibers significantly impacted the binder characteristics. The treatment of CB fibers with anhydrous ethanol was employed to remove the plasticizer glycerol triacetate (GTA), enabling the better homogeneity of the fibers in the binder. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to assess the effectiveness of the fiber treatment. A dynamic shear rheometer (DSR) was used to explore the properties of bitumen with varying CB contents (0%, 0.25%, 0.75%, and 1.25% by weight). A whole life cycle analysis further confirmed the eco-efficiency of CB binders. The results show that the pretreatment effectively removed GTA, leading to a more homogeneous dispersion of fibers in the binder. Adding CBs can significantly improve bitumen properties, but this effect does not increase with higher dosages; when the CB content exceeded 1.25%, a reduction in fatigue resistance was observed. Among the tested dosages, the optimal amount was 0.75%, which improved the high-temperature performance of the binder by 2.7 times, the medium-temperature fatigue life by 1.78 times, and the low-temperature performance by 1.08 times. In terms of ecological benefits, the addition of CB fibers to bitumen pavement reduced carbon emissions by two-thirds compared to traditional bitumen pavement, resulting in a significant decrease in carbon emissions. This study provides valuable insights into the construction of sustainable transportation infrastructure.