Impact of Interlayer Adhesion Characteristics on Asphalt Pavement Structural Thickness Design: From the Perspective of Fatigue Cracking of the Asphalt Surface Layer

To investigate the influence of interlayer bonding conditions on the determination of asphalt pavement structural layer thickness, this study develops a computational model of a granular base asphalt pavement structure that accounts for interlayer bonding conditions from the perspective of asphalt surface layer fatigue cracking. After verifying the reliability of the General Analysis of Multilayered Elastic System (GAMES) program in simulating these conditions, the program was used to analyze the relationships between surface layer thickness, base layer thickness, and asphalt surface layer fatigue cracking life under various interlayer bonding conditions, based on the fatigue cracking life prediction equation used in China’s highway industry. A method for adjusting the determination of asphalt surface layer thickness, considering interlayer bonding conditions, was proposed, along with recommendations for improving interlayer bonding. The results indicate that, regardless of the interlayer bonding conditions, the fatigue cracking life of the asphalt surface layer increases with the thickness of the asphalt surface layer and base layer, following an exponential equation and a linear equation, respectively. The fatigue cracking life of the asphalt surface layer is more significantly influenced by the surface layer thickness. In asphalt pavement structural design, the method described in this study can be used to adjust and increase the surface layer thickness to meet the fatigue cracking life requirements under the most unfavorable interlayer bonding conditions. It is also recommended to enhance pavement coats, apply geosynthetics, and use continuous construction methods to improve interlayer bonding conditions.