Effect of Loading Frequency and Temperature on the Fatigue Parameters of Asphalt Concrete

Abstract

Investigating the behavior of asphalt concrete at low loading frequency is essential to understand the thermal fatigue damage due to cyclic day-night temperature cycles, where the loading frequency is usually very low. This study determines some properties (e.g., fatigue damage, dissipated energy, and stiffness) of asphalt concrete beam samples at a low frequency of loading using four-point bending test apparatus. Results show that fatigue damage is more significant at a lower frequency of cyclic loading and the number of cycles at failure becomes stable at a frequency equal to or lower than 0.01 Hz. The concept of initial stiffness at the 50th cycle of loading is inappropriate at a low frequency of loading as the stiffness reduction with a number of loadings is so considerable at a frequency of loading. In addition, the dissipated energy per loading cycle decreases with a decrease in loading frequency.