Enhancing Bitumen Performance with Recycled Carbon Fiber-Reinforced Polymers: A Sustainable Approach to Waste Management

The widespread use of carbon fiber-reinforced polymer (CFRP) has resulted in a substantial increase in waste CFRP materials, presenting a significant global environmental challenge regarding their disposal. Recycling these waste CFRP materials would be an environmentally sustainable solution, but the diminished mechanical properties of recycled carbon fiber (rCF) restrict the utilization of rCF in high-precision industries. To address the potential to recycle rCF, this study incorporated rCF into bitumen to determine if rCF could enhance bitumen's mechanical performance. A comprehensive evaluation of the effect of rCF on bitumen's durability measured high-Temperature performance, resistance to fatigue, and low-Temperature performance. The enhancement mechanisms were determined by analyzing the thermodynamic properties and microstructural characteristics of base bitumen and bitumen with rCF. The results demonstrated that the incorporation of rCF increased the rutting resistance and fatigue resistance of bitumen, especially for rCF with a diameters ranging from 0.5 to 1.0 mm and a length of 10 mm. The rCF with a diameters ranging from 0.2 to 0.5 mm and a length of 5 mm was more beneficial for improving the low-Temperature cracking resistance of bitumen. The rCF with lower specific heat capacity enhanced heat absorption, thereby improving the high-Temperature resistance of the bitumen. In addition, the rCFs formed a three-dimensional network structure in bitumen; this structure restricted bitumen flow and reinforced the bitumen, thereby enhancing the low-Temperature cracking resistance of the bitumen. This study highlights the promising feasibility of integrating rCF into bitumen as an economically and environmentally sustainable solution for recycling waste CFRP materials.