A Comparative Study of Fatigue Analysis Methods Applied to Reinforced Asphalt Systems

This study presents findings obtained by applying three distinct methods to assess the fatigue resistance of double-layered asphalt systems: traditional (50% reduction in initial stiffness), energy ratio, and recently developed simplified flex point (SFP). Asphalt specimens with plain and polymer-modified bitumen were investigated using four-point bending beam test in both reinforced and unreinforced forms. Two different kinds of bitumen emulsion were used as the tack coat, plain and polymer-modified, whereas a polymer-coated fiberglass geogrid was used as reinforcement. The results revealed that the choice of fatigue analysis method may significantly affect the assessment of fatigue resistance. It was further discovered that the SFP method was found to provide an accurate representation of grid efficiency, particularly for specimens with plain bitumen. Results also demonstrated that grid reinforcement improves fatigue resistance for approximately 15–20 μm/m, regardless of the mixture type, highlighting its potential to increase pavement durability. However, the study emphasizes the necessity for additional investigations into various geogrid materials and the establishment of relationships between different analytical methods for more efficient pavement design.