Introducing asymmetric alternative fatigue: a numerical framework for asphalt pavements under combined thermal and vehicle loading

In traditional pavement analysis, repetitive loads are considered to be the dominant factor in pavement fatigue. Temperature variations produce cyclic thermal stresses in the pavement structure. When these thermal stresses are incorporated into load-fatigue analyses, the pavement may face more unfavourable service conditions. To investigate the true fatigue behaviour resulting from the combined effects of temperature and loading, this paper calculates the mechanical response of four typical asphalt pavement structures under the effect of temperature, vehicle load and the coupling of both factors and analyses how the mechanical indicators change over time at various depths within the pavement. The results reveal that the combined thermal and loading stresses create a novel asymmetric fatigue mode in asphalt pavements. Specifically, thermal stresses generate the minimum stress, while the maximum stress results from the coupling of temperature and vehicle load. This asymmetric fatigue pattern offers a more accurate and generalised representation of asphalt pavement fatigue.