Assessment of the impact of binder grade on the laboratory performance of fiber reinforced asphalt mixtures

Abstract

This study aims to evaluate the impact of different fiber types and binder modifications on the volumetric properties and performance (rutting and cracking) of fiber-reinforced asphalt mixtures (FRAM). Four types of fibers (carbon, fiberglass, basalt, and polyolefin/aramid (PFA) mix) and two binder performance grades (PG 58–28 unmodified and PG 76–22 polymer modified) were used to produce a total of ten asphalt mixtures (two control and eight FRAM). All fibers were introduced at the manufacturer-recommended dosages (i.e., carbon, fiberglass, basalt: at 0.16%, and PFA: at 0.05%) by mix weight. The mix design and volumetrics properties were examined to assess the impact of FRAM on volumetric properties of modified and unmodified binders. Mix characteristics, durability, rutting, and cracking performances were also evaluated by performing several tests, including dynamic modulus test |E*|, Cantabro loss, Asphalt pavement Analyzer (APA), Flow Number (FN), and Indirect Tensile Asphalt Cracking Test (IDEAL-CT). Mix design results showed that FRAM at 0.16% dosage increased the air voids of the unmodified binder (PG58-28). PFA fibers did not have an impact on air voids or volumetric properties of the asphalt mix regardless of modification. Performance results showed that FRAM were highly durable than control mix, but durability is significant for polymer modified binder (PG76-22). Furthermore, only PFA reinforced mixtures showed better rutting resistance for both modified and unmodified binders. The addition of fibers did not show any impact on cracking performance of modified and unmodified binder prepared asphalt mix. Finally, PFA reinforced mix also indicated higher fracture toughness (Gf) and carbon fibers improved the ductility of asphalt mix.