Fracture properties of ultra-thin friction course mixture containing reclaimed asphalt pavement and glass fiber under monotonic and cyclic loading

Abstract

Ultra-thin friction courses (UTFC) have demonstrated exceptional efficacy in the preventive maintenance of asphalt pavements. Despite this, research into the influence of reclaimed asphalt pavement (RAP) and glass fiber on the fracture behavior of UTFC mixtures under cyclic loading is sparse. In response, this study conducted both monotonic loading tests and tension cyclic loading tests on notched semi-circular specimens at a temperature of 25 °C to elucidate the impact of RAP and glass fiber on UTFC’s fracture resistance. The findings revealed that, during monotonic testing, the introduction of RAP appeared to bolster mechanical performance by increasing peak load and tensile stiffness index (TSI). However, RAP diminished the fracture energy, with the concurrent addition of RAP and glass fiber resulting in further compromise to fracture resistance. Conversely, in the cyclic loading tests operated under load control, the integration of RAP positively influenced fatigue life. Furthermore, the addition of 0.1 % glass fiber (identified as H-25R-0.1F) also improved fatigue life, highlighting its beneficial role in augmenting fatigue endurance. When compared to the mixture devoid of RAP, the inclusion of 25 % and 50 % RAP led to substantial increases in cumulative dissipated energy by 101 % and 398 %, respectively. These results suggest that both RAP and glass fiber have nuanced effects on the fracture and fatigue properties of UTFC mixtures, with potential implications for their application in roadway construction and rehabilitation. Minimum rate of cumulative dissipated energy change (RCDEC_min) could be used to characterize the fatigue performance. The lower the RCDEC_min, the larger the fatigue life. There existed a power law relationship between RCDEC_min and fatigue life, which was independent of the mixture type. Compared to the cumulative dissipated energy method, the maximum displacement method may be more suitable to characterize the damage evolution during the fatigue test.