Performance assessment of polyester fiber modified stone matrix asphalt mixtures with statistical analysis

There has been a surge in the use of more resilient and long-lasting asphalt mixes for the top layer, including stone matrix asphalt (SMA), which is a gap-graded mix comprising coarse aggregates around 70–80% of total aggregate mass, filler in the range of 8–12%, binder of about 6–7% and fibers amounting to 0.3–0.5%. This study aims to enhance the strength of SMA by incorporating varied dosages of polyester fibers (commercially named Recron Fibers-RF). Five distinct dosages of RF (0.3–0.7% with 0.1% increment) were incorporated into the SMA mixture in place of conventional cellulose fiber. A series of performance measures including drain down, Marshall stability/flow, Indirect Tensile Strength (ITS), Indirect tensile stiffness modulus (ITSM), dynamic modulus, flow number, fatigue life, and retained Marshall stability (RMS) were conducted on normal SMA (NSMA-containing cellulose fibers) and SMA-RF mixtures (containing varied dosages of RF). The drain-down tests demonstrate that Recron fiber can replace cellulose fiber in SMA mixes to prevent asphalt drain-down during manufacturing. The recron fiber content of 0.4% (0.4RF) behaved very well in all mechanical performance tests, especially against rutting which was 20% more than that of NSMA. SMA-0.4RF mix also reported about a 17% increase in fatigue life concerning NSMA. ANOVA test results and boxplot analysis show that while certain mix properties, such as ITS and Marshal Flow, demonstrate consistent performance with minimal variability within groups, others like Resilient Modulus and Fatigue exhibit higher variability, potentially indicating diverse material behaviors or experimental conditions. The statistical approach reflects novel inference for future application in the paving industry.