Micromechanical behavior of single fiber-asphalt mastic interface: Experimental studies by self-designed innovative pullout test

Abstract

Micromechanical behavior of the interface between fiber and asphalt is a crucial factor in the performance of fiber reinforced asphalt concrete, and a thorough understanding of this behavior is essential for the design and optimization of these materials. To evaluate the micromechanical behavior of the interface, an innovative single fiber pullout test platform was designed, and the experimental parameter conditions were systematically studied. Three types of fibers including basalt fiber (BF), glass fiber (GF) and polyester fiber (PF) were adopted, and the pullout test was performed at 60 ℃, 25 ℃ and −10 ℃, respectively, where the micromechanical behavior at the interface under different experimental conditions was obtained. The results showed that the recommended loading rate of the fiber pullout test is 1–3 mm/min, and the measurement of variability is satisfactory. The single fiber pullout behavior was observed and the load-displacement curve was recorded real-time. Three failure modes (fiber pullout, fiber fracture and matrix failure) at the interface between the single fiber and asphalt mastic were observed. Furthermore, a bond-slip model which can accurately characterize the bonding-debonding behavior of the interface between the single fiber and asphalt mastic was established. It was found from the study that micromechanical behavior of the interface between the single fiber and asphalt mastic is influenced by the type of fiber and temperature, the peak load and displacement are significantly different. These findings presented in this study can play a significant role in revealing the reinforcement mechanism of fiber and providing a guidance for the efficient application and development of fiber reinforced asphalt mixture.