Enhanced Viscoelastic Modeling Of Hot Mix Asphalt

Abstract

The primary objective of this research is to investigate the relationships between Compressive (CDM) and Tensile Dynamic Moduli (TDM) of Hot Mix Asphalt (HMA) and develop a material model that predicts tensile dynamic modulus from known compressive dynamic modulus. Moreover, the research develops an enhanced visco-hyper-elastic Finite element model that incorporates both CDM and computed TDM to predict the structural response of a perpetual pavement structure subjected to wheel loading. In the laboratory, the Compressive and Tensile Dynamic Modulus parallel to the direction of compaction and Tensile dynamic modulus perpendicular to the direction of compaction were determined at different temperature and frequencies. The results of the experiments were used to develop relationships between Compressive and Tensile dynamic modulus at 10°C, 20°C, 30°C, 35°C and all temperature combined. The research found that the data correlation at each temperature levels increased with temperature from fair to good (R2 = 0.5-0.85) whereas the correlation at all temperature combined was strong (R2 = 0.91). The model corresponding to the highest R2 was evaluated for accuracy and rationality. This research incorporated both Compressive and computed Tensile Dynamic Moduli (based on the best model) into a visco-hyper-elastic FE model to predict strain responses of the Kansas US75 perpetual pavement sections. This research developed mathematical models that may be used by engineers and researchers to estimate tensile dynamic modulus from known compressive dynamic modulus. In addition, the research demonstrated that the enhanced visco-hyper-elastic finite element model that incorporates both Compressive and Tensile moduli can predict HMA pavement responses.