ABSTRACT
The rutting damage evolution and changes in microstructures of porous asphalt (PA) mixture are still unclear under coupled effects of high temperature and moisture. A new approach combining a staged multiphysics repeated loading permanent deformation test and X-ray computed tomography technology was developed to investigate the damage evolution and changes in microstructure under dry and coupled conditions. Densification was found at the primary stage with a decrease in total air void content (AVtotal) and interconnected air void content (AVinterconnected). Coupled effects have a greater densification function than dry conditions in the primary stage. In the secondary stage, AVtotal, AVinterconnected, and total AV number are increased. Shear failure was found in the tertiary stage under the coupled condition with an increment of AVtotal and AVinterconnected, while densification failure was found under the dry condition with a decrement of AVtotal and AVinterconnected. Under the dry conditions, radial deformation grows faster than the vertical deformation in the primary and secondary stage, while slower in the tertiary stage. However, the radial deformation grows faster than the vertical deformation through the test under the coupled effects. The coupled effects have a remarkable influence on the rutting damage evolution and failure mechanism of the PA mixture.
Disclosure statement
No potential conflict of interest was reported by the author(s).