Enhancement of Hot Asphalt Mixture Performance through the Incorporation of Carbon and Polyester Microfibers

Abstract

This study explores the performance enhancement of hot asphalt mixtures by integrating carbon (MCF) and polyester (MPF) microfibers. Conventional asphalt mixtures (M0) encounter issues such as rutting, moisture damage, and thermal cracking due to increasing traffic and environmental stressors. Fiber-reinforced asphalt mixtures (CFRAMs and PFRAMs) were created with fiber contents from 0.25% to 1.5% by weight. Laboratory evaluations assessed Marshall properties, moisture susceptibility (through immersion Marshall and freeze-thaw splitting tests), and high-temperature rutting resistance (wheel tracking tests at 40°C and 60°C). The results indicated that both types of fibers enhanced mechanical performance, reaching optimal results at 0.75% fiber content. CFRAMs displayed the highest Marshall stability (17.5 kN compared to 12.5 kN for M0) and Marshall stiffness (6.18 kN/mm), as well as greater moisture resistance (tensile strength ratio >85% in contrast to 80% for M0). Polyester fibers showed a higher water absorption rate (2.43% versus 1.87%) and reduced thermostability compared to carbon fibers. Wheel tracking tests verified the outstanding rutting resistance of CFRAMs (with a proportional rut depth of 0.067 at 40°C compared to 0.211 for M0), particularly at high temperatures. The study concludes that microfibers significantly improve the durability of asphalt, with carbon fibers demonstrating superior performance for sustainable pavements in challenging conditions.