DEVELOPING A MODEL TO PREDICT THE PULSE DURATION OF TENSILE RESPONSE AT THE BOTTOM OF ASPHALT LAYER Print

Fatigue damage is one of the most important distresses in asphalt pavements. Fatigue cracking is influenced by many factors such as pavement structure, loading and environmental conditions and the shape and duration of tensile response pulses at the bottom of asphalt layer greatly affects fatigue life of apshlat layer. In this study, both thick and thin pavement structures in different conditions were analyzed by the 3D-Move program. In the analysis, the asphalt layer was treated as viscoelastic and other layers were considered as elastic material. Haversine and bell-shape functions were fitted to the tensile response pulses computed using dynamic analysis. The results showed that the vehicle speed, thickness of asphalt pavement, pavement temperature and radius of the contact area are the most important factors that affect the shape and duration (frequency) of the tensile response pulses at the bottom of the asphalt layer. In this study, two general models are presented to predict the duration of stress and strain response pulses in longitudinal and transverse directions based on the haversine and the bell-shape waveforms.