Abstract: For the impervious layer in hydraulic asphalt concrete panels, this study examine its crack-healing characteristics by conducting beam bending tests, crack observation, and ultrasonic non-destructive testing on fiber-reinforced asphalt concrete. We make a comparative analysis of its crack-healing behaviors with those of the reference asphalt concrete, focusing on mechanical properties and structural integrity. Experimental results show that after seven days of a fiber concrete specimen immersed in water, its fibers￠ adsorption effect and elastic properties maintain the stability of its mechanical properties. Its bending healing rate reaches up to 95%, whereas the reference concrete has a rate as low as 41%. Water environment promotes surface healing significantly, with the highest rate up to 97%, far superior to that in dry conditions. For the fiber concrete, its internal damage healing is characterized with hysteresis-strengthening. The initial-stage healing hysteresis is attributed to the oil absorption effect of fibers, increasing the thickness of structural asphalt, while the synergistic deformation of fibers and asphalt ensures excellent continuous healing performance in the period of seven days. This study further achieves a multi-index collaborative evaluation method for the crack-healing performance of fiber-reinforced hydraulic concrete, and lays a basis for its engineering application.

Key words: hydraulic asphalt concrete, impermeable panel, crack healing, fiber, ultrasonic nondestructive testing