Effect of synthetic fiber state on mechanical performance of fiber reinforced asphalt concrete

It has been recognized that there exists a potential benefit from using synthetic fibers to reinforce asphalt mixtures. In these mixtures, the state of the fibers may play an essential role in their reinforcement function. This study aims to quantify the state of synthetic fiber distribution for two different aramid fiber-based asphalt mixtures and then show the impacts of fiber dispersion on modulus, rutting, and fatigue performance of each asphalt mixture in comparison with one another and with respect to an equivalent non-reinforced asphalt mixture. Both a quantitative and qualitative assessment of aramid fibers distribution as well as state of fiber are investigated using a fiber extraction procedure and microscopy imaging, respectively. The results suggested that a higher level of micro-fibrillation as well as high distribution of aramid fibers improved the rutting resistance of asphalt mixtures, while the distribution level of aramid fibers and fibers state did not affect the modulus and fatigue. These results are specific to the mixture studied but provide the first objective and detailed study describing fiber state, fiber dispersion, and performance.