Reinforcing filaments or fibers, such as aromatic polyamide (aramid) fibers, can be reliably measured and consistently mixed into asphalt cement concrete by soaking the fibers in a wetting agent, then severing them to a desired length, and mixing the segments with other ACC ingredients. The wetting agent holds the fibers together loosely, so they can be distributed more uniformly throughout the ACC without clumping. The wetting agent soaks into the ACC mixture and/or evaporates, leaving the reinforcing fibers behind.