A Comparative Study of Laboratory Measured and Predicted Dynamic Modulus for Characterizing Florida Asphalt Mixtures

Fatigue cracking under repeated load is one of the primary factors to be considered for flexible pavement design. Dynamic modulus test appeared to be a promising simple performance test for linking fundamental material properties to fatigue cracking observed in the field. The dynamic modulus concept was introduced in the AASHTO mechanistic-empirical pavement design guide as one of the critical inputs for characterization of asphalt concrete mixture, and it is employed as a key parameter in most commonly used models to predict fatigue life of bituminous mixtures. This paper presents a laboratory experimental program to evaluate the dynamic modulus of Florida Superpave asphalt mixtures including granite and limestone materials. The dynamic modulus master curves were constructed using the time-temperature superposition principle. The results indicated that the master curves for same type of materials were similar in shape and close to each other. The Witczak prediction model was used to perform a comparison between the measured and predicted dynamic modulus. The comparison showed that the Witczak prediction model provided a good estimation and could be adopted for estimating the modulus characteristics of commonly used Florida asphalt mixtures.