Rutting resistance of porous asphalt mixture under coupled conditions of high temperature and rainfall

Porous asphalt (PA) mixtures work real coupled conditions of high temperature and rainfall in rainy summer weather. The objective of this study is to develop a multi-physics repeated loading permanent deformation (MRLPD) test that can evaluate the rutting resistance of the PA mixture under such real coupled conditions. A multi-physics chamber was designed for the MRLPD test to achieve real coupled conditions of dry, rainfall onset, ongoing rainfall, and rainfall end, which are consistent with the rainfall process. Under the rainfall onset and ongoing rainfall conditions, the rutting resistance of the PA mixture is lower than that under the dry condition. PA mixture shows the poorest rutting resistance under the ongoing rainfall condition. The presence of water in the pores creates pore pressure, which facilitates moisture damage and consequently decreases the rutting resistance. The more time the PA mixture stays in a saturated state, the lower the rutting resistance is. PA mixture exhibits the best rutting resistance under the rainfall end condition because the pore pressure absorbs part of the loads and the decreased temperature of the specimen. The rutting resistance of the PA mixture is more sensitive to temperature and overloading than to moisture damage. Under the coupled conditions, high temperature accelerates the evolution of moisture damage, which leads to the acceleration of rutting failure.