Study on the deterioration characteristics of physical-mechanical properties in pervious pavement concrete under hydrodynamic leaching action

In a rainwater environment, the dynamic water pressure caused by vehicle wheel loads and the accumulation of water on the pavement together generate leaching effects, which impact the physical and mechanical properties of pervious concrete pavements. A self-developed hydrodynamic leaching coupling test device was used to simulate the dynamic water leaching of the pavement, and the physical and mechanical properties of the pervious concrete before and after leaching were tested. Optical microscopy (OM), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to analyze the microstructural changes during the leaching process and summarize the degradation mechanisms. The results show that under hydrodynamic leaching coupling conditions, the degradation of the physical properties of the pervious concrete occurs faster than under single hydrodynamic conditions, with the loss rates of mass, compressive strength, and splitting tensile strength reaching up to 9.04 %, 25.08 %, and 29.86 %, respectively. Under the same leaching conditions, the splitting tensile strength loss rate is higher than the compressive strength loss rate, indicating that splitting tensile strength is more sensitive to leaching than compressive strength. Under hydrodynamic action induced by vehicular traffic, the leached microstructure of pervious concrete pavement becomes loose, with microcracks connecting through pre-existing defects and gradually developing into major cracks. The leaching-induced damage is primarily attributed to crack propagation and leaching-induced abrasion. The research findings provide a deeper understanding of the deterioration behavior of pervious concrete under hydrodynamic leaching. These results can serve as a foundation for future studies aimed at mitigating leaching damage of pervious concrete pavement under coupled hydrodynamic conditions.