Laboratory performance characterization of polyolefin/ aramid fibers and synthetic aramid fibers reinforced asphalt mixtures

This study was conducted to assess the impact of combined polyolefin/aramid fibers (PFA) and pure synthetic aramid fibers (AF) reinforcement on mix design properties and laboratory performance. The study also investigated the shift in laboratory performance (rutting to cracking and vice versa) with the addition of both type of fibers. One aggregate (diabase stone), one binder type (PG58–28), and two types of aramid fibers (combined polyolefin/ aramid fibers and synthetic aramid fibers), added at 0.05% dosage by mix weight, were used to produce two fiber-reinforced asphalt mixtures (FRAM). Additionally, a control mix was also produced without any reinforcement. Mix design for control and FRAM was performed and Optimum Binder Content (OBC) was determined. The laboratory rutting and cracking performance of the mixtures was assessed using Asphalt Pavement Analyzer (APA), Flow Number (FN) and Indirect Tension Asphalt Cracking Test (IDEAL-CT). Durability and stiffness of these mixtures were also determined by performing Cantabro loss and Dynamic Modulus (DCM) tests. According to the mix design results, PFA reinforced mix showed an offset bulk and theoretical maximum specific gravity. However, both control and FRAM mixtures showed the same OBC (5.7%). Both type of fibers improved the durability of mix. With addition of PFA and AF fibers into the asphalt mix, the performance trend shifted from rut resistant mix to crack resistant mix, respectively. Furthermore, addition of PFA fibers into the asphalt mix increased the toughness and AF fibers make the asphalt mix ductile.