Effect of temperature on fatigue damage evolution of asphalt mixture based on cluster analysis and acoustic emission parameters

Fatigue cracking severely impacts the structural integrity and service life of asphalt pavements. Temperature modifies asphalt mixture responses to traffic loading and fatigue resistance by altering binder properties. This study comprehensively characterized temperature-dependent fatigue behaviors through integrated experimentation and data analysis. Four-point bending tests were conducted on asphalt beams at 15 degrees C, 20 degrees C and 25 degrees C combined with acoustic emission monitoring. A series of parameters, including the b-value and S-value, were extracted from the acoustic emission signals to characterize the damage stages. Cluster analysis classified dominant cracking modes associated with temperature. Digital image correlation validated crack propagation patterns. Results showed significant reductions in fatigue lives with 5 degrees C increments across the intermediate temperature range. Three distinctive damage stages were consistently identified irrespective of changing temperature. Clustering revealed tensile cracking comprised over 89% of events, increasingly favored by higher temperatures up to 25 degrees C. Peak frequency shifts correlated rising temperatures with earlier micro-macro scale transitions. Digital image correlation supported faster crack growth kinetics at elevated temperatures. Key findings provided new perspectives on temperature accelerating microcrack initiation, linkage and macrocrack propagation governing failure.