Correlating the Fatigue Response of Asphalt Binders and Mixtures Prepared Using Warm-Mix Asphalt Technologies

This study assessed the influence of warm-mix asphalt (WMA) technologies on the fatigue behavior of asphalt binders and mixtures. The aim was to investigate the potential correlations between the fatigue test parameter values determined by testing asphalt binders and mixtures. The material combination used for the experimental work comprised two base asphalt binders (unmodified and polymer-modified binder), two aggregate sources (granite and dolomite), and five different WMA additives (Sasobit, Sasobit Redux, Rediset, Cecabase, and Aspha-min). The prepared asphalt binders were tested using the frequency sweep and linear amplitude sweep (LAS) tests, while the asphalt mixtures were characterized using the ideal tensile cracking test. The test results indicated that including WMA additives in an unmodified binder improved the fatigue resistance; however, their effect in the polymer-modified binder was relatively low. Nonetheless, all the WMA binders and mixtures performed almost equivalent to their respective base binders and mixtures. Among the different classes of WMA, the use of chemical-based additives demonstrated better fatigue resistance. The correlation between the fatigue life of asphalt binders and the fatigue index (FI) of asphalt mixtures was found to be the function of strain level, as observed through the change in the coefficient of determination (R2) value. Based on this correlation, the critical FI value for fatigue-resistant asphalt mixtures was analyzed to be 470, 430, and 415 for very heavy/extreme, heavy, and slow traffic conditions, respectively.