沥青路面的双向疲劳损伤

Fatigue damage is an important issue in the technical system of asphalt pavement and the corresponding fatigue design models have been established in various design methods. The fatigue evolution behavior of asphalt pavement in the life cycle was studied and 60 million loading tests were applied on the full-scale accelerated loading test track (RIOHTrack). Different fatigue damage conditions from 19 test sections were obtained and a bidirectional fatigue damage mode of asphalt pavements was presented. In this mode, under the action of a driving load, the asphalt pavement undergoes both top-down and bottom-up fatigue damage. The top-down fatigue damage is caused by a compression or shear load and can be generally manifested as the dual damage between the transverse top-down fatigue cracking and rutting deformation. Bottom-up fatigue damage is a traditional fatigue damage mode, caused by the flexural load at the bottom of the whole material structural layer. It is important to note that the flexural fatigue failure of a single structural layer does not lead to the failure of the whole structure, that is, the fatigue life of a structural layer is not equal to the fatigue life of the whole structure. In this paper, based on the bottom-up fatigue damage mode, a layer-by-layer accumulation analysis method of fatigue life is proposed to improve the assessment of flexural fatigue life of asphalt pavement.