Abstract: Under the long-term action of water, temperature and load, the service life of asphalt pavement is significantly reduced. In order to explore the decay law of asphalt mixture road performance, a dynamic water scour simulation test device for asphalt mixtures was independently developed. The asphalt mix Marshall specimens were subjected to multiple freeze-thaw cycles-dynamic water scouring cycles to analyze the change law of asphalt mix characteristics parameters, combined with CT slice scanning to explore the law of internal structural changes of asphalt mixes. The results show that each characteristic parameter shows a faster growth or decay in the pre-freeze-thaw cycle-dynamic water scour cycle. Under the action of applied dynamic water pressure, the internal water absorption of asphalt mixture will gradually increase to the full water state, and the micro-open pores inside the asphalt mixture specimens will undergo structural and morphological changes. The splitting strength of the asphalt mixture was reduced by up to 65.44% after 12 freeze-thaw cycles-dynamic water scouring cycles. The research results provide a theoretical basis for further understanding of the water damage mechanism of asphalt pavements.

Key words: asphalt mixture, freeze-thaw cycles, moving water scouring, SMA-13, characteristic parameters