Carbon Fiber Powder as a Microwave-Sensitive Filler in Asphalt Mastic: Improving High-Temperature and Fatigue Resistance Properties

Improving the microwave self-healing capability of asphalt mixtures contributes to reducing carbon emissions during maintenance and lowering costs over the road's lifespan. Based on the prestudy of this current work, the feasibility of using a microwave-sensitive material, carbon fiber powder (CFP), as a filler in the preparation of microwave-absorbing asphalt mixtures was investigated in this research, from the perspective of asphalt mastic rheological behavior. The study commenced by delving into the particle size distribution and microwave heating characteristics of the two fillers. Subsequently, the five asphalt mastics underwent four rheological tests: temperature sweep, multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), and frequency sweep tests to explore the high-temperature, fatigue resistance, and cracking resistance properties of the asphalt mastics. The results reveal that CFP exhibits a significantly greater microwave heating capacity, with a microwave heating rate 19 times greater than that of limestone powder (LP). Compared to conventional asphalt mastics, CFP-based asphalt mastics demonstrate enhanced resistance to high-temperature permanent deformation and fatigue. The addition of CFP can effectively prolong the fatigue life of asphalt mastics. Moreover, CFP-based asphalt mastics exhibit cracking resistance comparable to that of traditional asphalt mastics. The CFP replacement rate has a statistically significant effect on the high-temperature and fatigue resistance of asphalt mastics. CFP-based asphalt mastics with a 100% substitution rate demonstrate superior high-temperature and fatigue resistance, perhaps attributed to the smaller particle size of CFP, which is beneficial to its interaction with asphalt, ultimately improving the performance of CFP-based asphalt mastics.