Fiber reinforcing effect on asphalt binder under low temperature

• We investigate fiber reinforcing effect on asphalt binder under low temperature.
• Fiber pullout strength can exceed fiber strength due to asphalt coating effect.
• Aramid fiber needs longer embedment length to develop bond than polyester fiber.
• Addition of polyester fiber can greatly enhance failure tensile strain of asphalt.
• Fiber reinforced asphalt mains its tensile ductility with decreasing temperature.

This research examines reinforcing effect of different fibers on asphalt binder under low temperature. Laboratory test of multiple-fiber pullout (MFPT) from asphalt matrix was conducted to investigate the influence of fibers (fiber type and embedment length) and matrix (asphalt binder type) on the fiber pullout strength. Furthermore, the influence of fiber (with or without fiber, fiber length and dosage) and matrix (asphalt binder type and temperature) on the tensile properties of fiber reinforced asphalt (FRA) binder was investigated via direct tensile test (DTT). From the MFPT test it was found that fiber pullout strength can actually exceed the fiber strength provided by the manufacturer, presumably due to coating effect of the asphalt on the surface of fibers. Aramid fiber requires much longer embedment length to fully activate its bond with asphalt than the polyester fiber does. From the DTT test it was observed that addition of adequate polyester fiber can greatly enhance the tensile properties of the FRA, particularly in terms of failure tensile strain. While asphalt matrix becomes more brittle when temperature drops, FRA mains its tensile ductility with decreasing temperature, which deserves further investigation.