A self-developed measurement system-based insights into pore water transfer within asphalt concrete under tire–pavement interaction: Water scouring effect and material damping effect

Rainfall infiltration and subsurface moisture migration often result in water accumulation within asphalt pavement, causing it to operate in saturated or partially saturated conditions. Under repeated tire–pavement interactions, this trapped water generates dynamic pore water pressure (PWP), which drives complex fluid–structure interactions and contributes to moisture-induced damage. In this study, a novel PWP simulation and measurement system was developed to capture transient pore pressure responses in both time and depth domains. The results revealed that PWP in asphalt concrete exhibited rapid rise and decay followed by progressive accumulation under cyclic loading, with a clear longitudinal lag in dense specimens. Alternating compression–suction cycles and pressure reversals were identified as the primary mechanisms driving hydraulic scouring within the pore network. Within a moderate porosity range (6.3–9.8%), enhanced hydraulic resistance amplified scouring effects of pore water, whereas excessive porosity (>10%) weakened pressure buildup due to increased permeability. Furthermore, PWP peaks attenuate and energy dissipation increased with depth, reflecting the damping effect of asphalt concrete under fluid–structure interaction. These findings clarify the coupled hydraulic and mechanical processes responsible for energy dissipation and water-induced deterioration in porous asphalt pavements, offering new insights for improving their durability and hydrodynamic performance.