Effect of aging on the low-temperature performance of fiber-reinforced asphalt mixtures

Abstract

To study the effect of aging on the low-temperature crack resistance of fiber asphalt mixes, three kinds of fibers (lignin fiber, polyester fiber, and basalt fiber) were dry blended into AC-13 asphalt mixes to prepare unaged, asphalt aged (that is, the original asphalt material is subjected to aging treatment), short-term aged, and long-term aged fiber reinforced asphalt mixes. Semicircular bending (SCB) tests and scanning electron microscopy tests were used to analyze and study the effects of aging time and fiber type on the low-temperature properties of asphalt mixtures at an ambient temperature of −5 °C. The SCB test results indicated that: with the deepening of aging, the fracture toughness and fracture energy of the fiber asphalt mixture specimens will tend to decrease, and the aging of the original asphalt has a greater impact on the specimens without fiber; there was great variability in the effect of lignin fibers on the crack resistance of the mix, but it could be a good promoter in unaged asphalt mixes; polyester fiber is the material of choice for improving low-temperature crack resistance in long-term aging pavements; the incorporation of basalt fiber greatly enhances the crack resistance of asphalt mixes and is an excellent material for improving aging asphalt mixes. It is clearly seen by the scanning electron microscope test that with the deepening of aging, the adhesion of asphalt and aggregate gradually deteriorates, and even more so, there is the phenomenon of fine aggregate flaking, and the fiber cannot play an excellent role in reinforcement and crack resistance.