Abstract: To investigate the degree of correlation between the fatigue life of interlayer shear in asphalt pavement and the contributing factors, a shear fatigue test was assembled. A conprehensive series of interlayer shear fatigue tests of asphalt mixtures with different composite structure layers were carried out on the UTM-100 asphalt pavement universal test material machine. The shear fatigue test encompass different composite structural layer types, different viscous layer oil types, different loading frequencies, different stress levels and temperature effects. The degree of correlation between these influencing factors and the fatigue shear life are employed based on the grey entropy theory. The results show that the SBS-modified asphalt binder material exhibits markedly superior interlayer shear fatigue performance compared to modified emulsified asphalt binder material, with the latter outperforming base asphalt binder material. When the stress level was increased from 0.3 to 0.4, the interlayer shear fatigue life of the asphalt mixtures was all reduced by approximately 60% to 65%, and the interlayer shear fatigue life of asphalt mixtures was reduced by approximately 45% to 65% when the temperature was increased from 20°C to 30°C. The degree of relationship between the interlayer shear fatigue performance of asphalt mixture and its influencing factors ranks as follows: loading frequency > stress level > temperature > type of viscous layer oil.

Key words: asphalt mixture, gray entropy theory, shear fatigue, interlayer, influencing factors