Fiber-Modified Open-Graded Friction Courses: Unveiling Enhanced Workability and Durability in Pavements

Open-Graded Friction Course (OGFC) mixtures in flexible pavements are known for their efficient drainage characteristics, but concerns exist regarding their structural weaknesses and short lifespans. This study investigates methods to improve the mechanical performance of OGFC by optimizing the mix design with the introduction of two different fibers. Sisal and glass fibers were each added (0.15%, 0.3%, and 0.45%) to OGFC mixtures containing 5%–6.5% bitumen binder (0.5% increments) and 2% pond ash filler. Different fiber-based OGFC mixtures were tested for volumetric properties and mechanical characteristics such as draindown, air voids, permeability, aging, Cantabro abrasion, and indirect tensile strength. Both fiber types showed improved mechanical performance, at a 0.3% fiber dosage. Glass fibers exhibited a higher tensile strength ratio (94.27%) compared to sisal fibers (93.81%), exceeding the required criteria by a significant margin. Finally, 0.30% fibers by weight of mix was selected as the optimum dosage for OGFC mixes inclusive of glass and sisal fibers.