Effect of treated fibers on performance of asphalt mixture

Abstract

In this study, a fiber surface treatment (coating technique) was developed using paraffin wax and warm-mix additive (WMA) to enhance fiber’s distribution throughout the asphalt mixture. Three types of fiber were examined, including WMA coated fiber, wax coated fiber, and uncoated fiber. The performance of fiber-reinforced mixtures was investigated by indirect tensile asphalt cracking test (IDEAL- CT), dynamic modulus, flow number, and overlay testing. Two mixing methods (e.g., dry and wet) were employed to determine the best mixing method. The promising results indicated the potential of incorporating warm-mix additive and fiber. Although Tukey-Kramer statistical analysis showed no significant difference between wet and dry mixing methods, the wet mixing method was recommended to mitigate the adverse mixing effects (e.g., fiber clustering, fiber sticking on the mixer). The insignificant difference between wax-coated fiber and uncoated fiber mixtures indicated the critical impact of coating materials on performance of reinforced asphalt mixture. Finally, mixtures containing 0.05% of WMA coated fiber suggest potential improvement in the performance of asphalt mixture, such as enhancing the cracking tolerance index (CTIndex), prolonging fatigue life, and exhibiting good resistance rutting.