Study on the microscopic damage of porous asphalt mixture under the combined action of hydrodynamic pressure and ice crystal frost heave

Abstract

Hydrodynamic pressure and frost heaving damage of ice crystals are the main reasons for the damage of porous asphalt mixture pavement in winter. Therefore, the author takes the open graded friction course (OGFC) asphalt mixture as an example, uses ANSYS finite element software to conduct multi-field coupling analysis of fluid and temperature for OGFC-13 asphalt mixtures with different porosities, pore structures, and different temperatures. Results show that the phenomena of “washing” and “pumping” of dynamic water exist in the connected pores at the same time. Under low-temperature conditions, low speed and heavy load are the most disadvantageous to the pores of the pavement surface. The maximum positive and negative pressures were 1.162 and −0.616 MPa, respectively. The wall shear stress distributed at the entrance and exit of the pores also reached peaks of 33.40, 25.77, and 20.07 kPa at the load duration T/2. In the early stage of ice crystal development, the temperature was lower, the temperature difference was greater, and the freezing rate was faster. In the later stage, the temperature difference decreased, the freezing rate decreased, and the same temperature value as the asphalt mixture matrix was finally reached. In addition, under the combined influence of temperature and air voids contents, the maximum stress value in the bonding surface near the connected pores was 2.89 MPa, which was 1.5 times the maximum stress value in the asphalt mortar. Under the interaction of hydrodynamic pressure and frost heave force, the upper layer of porous asphalt concrete pavement in contact with the wheels is destroyed earlier than the internal structure of the pavement. This article provides a quantitative expression for the hydrodynamic pressure and frost heave damage of porous asphalt pavement. Also, it reveals the influence of ice and snow melt on the macro performance of asphalt pavement from a meso-level perspective.