Environmental Influence on Visco-Elastic and Visco-Plastic Behavior of Asphalt Concrete

The asphalt concrete behavior through the Visco-plastic and Visco-elastic stages of failure is highly susceptible to the variation in the temperature of the pavement. In the present work, slab samples of asphalt concrete were prepared with the optimum asphalt binder requirement with the aid of laboratory roller compactor. Beam specimens of asphalt concrete were obtained from the prepared slab samples and tested under the influence of dynamic flexural stresses for fatigue life at constant strain level of 750 microstrain. Specimens were tested at three testing temperatures of (30, 20, and 5) ℃. The variations of the behavior through Visco-plastic and Visco-elastic modes in terms of phase angle, permanent deformation, flexural stiffness, and cumulative dissipated energy with the testing temperatures have been assessed. It was verified that at the end of the Visco-plastic stage of failure, the energy dissipation of the mixture increased by (2, 1.5, and 29) folds at the testing temperatures of (5, 20, and 30) °C respectively as compared with the energy dissipation at the end of the Visco-elastic stage of failure. The phase angle declined to (55, 20, and 30) ° at (5, 20, and 30) °C testing temperatures respectively at the end of Visco-plastic stage of failure as compared with that at the end of Visco-elastic stage of failure. The flexural stiffness at the Visco-plastic stage of failure declined by (60, 80, and 92) % at (5, 20, and 30) °C testing temperature respectively as compared with the flexural stiffness at the Visco-elastic stage of failure.