New phenomenological approach for modeling fatigue life of asphalt mixes

In this study three different aggregate gradation as per Ministry of Road Transport and Highways (MoRT&H), India, were evaluated for fatigue life determination using four point beam bending (4PBB) test. Sinusoidal loading with 10 Hz frequency was applied in controlled strain mode at 20 °C. All the mixes were compacted to an air void content of 4 ± 0.2%. Tests like retained Marshall stability and Indirect Tensile Strength (ITS) were also carried out to judge the mix performance. A new phenomenological model has been proposed for determination of the fatigue life of asphalt mixes. Experimental studies show that elastomeric modified bitumen display the highest fatigue life with least susceptibility to change in strain amplitude. Plastomeric modified mixes are found to be highly vulnerable to strain giving poor results at higher strain levels. The fatigue life of Stone Mastic Asphalt (SMA) is almost five times higher than the dense graded mixes. The new proposed model gives excellent fit with the experimental results and is statistically more reliable than the traditional modeling techniques.