Performance damage evolution of asphalt mixture under large/quick humidity-temperature fluctuation cycles

The humidity-temperature effect has been recognized as a major cause of asphalt pavement failure in southern regions of China. To study the characteristics of asphalt pavement materials under frequent high-temperature/cloudburst/high-temperature (large/quick humidity-temperature fluctuation cycles, HTF cycles) conditions, Abaqus and ArcGIS software were used to determine the parameters for HTF cycles laboratory test. Simulated tests were conducted on three-layer rutting specimens/Marshall specimens using a self-designed HTF cycles environment chamber. Finally, the specimens were subsequently sectioned, and performance tests were conducted using uniaxial compression tests, flexural creep tests, and indirect tensile fatigue tests (stress ratios were 0.3, 0.4, and 0.5). Based on the test results, curve fitting and fatigue performance damage models were established. The study indicated that a rainfall intensity of 30 mm/h and a pavement surface temperature of 70 ℃ should be set as the parameters for HTF cycles test. The mechanical properties and high-temperature performance of asphalt mixtures were significantly reduced under these conditions, with a more severe impact observed in middle layer materials (dense-graded asphalt concrete with a maximum nominal aggregate size of 20 mm, AC-20). In contrast, the fatigue performance of upper layer materials (stone matrix asphalt with a maximum nominal aggregate size of 13 mm, SMA-13) was more notably degraded. After 50 cycles of HTF cycles, the flexural tensile strength and compressive strength of the AC-20 mixture exhibited reductions of 61.2 % and 51.7 %, respectively. Meanwhile, the fatigue life of the SMA-13 mixture decreased by 74.3 % under a controlled stress ratio of 0.5. The correlation analysis reveals that the influence of HTF cycles loses prominence under conditions of a high-stress ratio to fatigue performance. The coefficient of determination of the established equation for predicting fatigue performance exceeded 0.9 and has good predictive accuracy. The findings offer practical guidelines for material selection and pavement design for the southern coastal regions of China. • The performance damage of asphalt mixes was analysed under large/quick humidity-temperature fluctuation cycles. • The fatigue life prediction equation has been optimized. • The performance damage degree differs between the upper and middle layers.