Impact of pore geometry on mechanical properties and anti-clogging efficiency in porous drainage pavement structures

Pervious concrete, a fundamental material in sponge city development, plays a vital role in mitigating surface runoff through enhanced rainwater infiltration. However, its long-term effectiveness is hindered by particle-induced pore blockage, which significantly reduces the permeability coefficient. Additionally, conventional pervious concrete often exhibits inadequate mechanical strength, limiting its capacity to regulate urban waterlogging and mitigate the heat island effect over time. This study integrated silica fume, polypropylene fibers, and a polycarboxylate superplasticizer into a self-compacting concrete matrix, utilizing 3D printing technology to fabricate porous drainage pavement structures with varied pore geometries. Finite element simulations using ANSYS were employed to evaluate the impact of five pore shapes on mechanical performance, complemented by experimental validation. The results reveal that structures with circular pores demonstrate superior performance, achieving a compressive strength of 50.71 MPa and a splitting tensile strength of 4.73 MPa. The close agreement between simulation and experimental results, with deviations within 4 %, underscores the reliability of the simulation model. Furthermore, circular pore structures exhibited the highest permeability coefficient (26.51 mm/s) and the lowest clogging mass fraction (3.23 %), confirming their enhanced hydraulic and anti-clogging capacities. Overall, the proposed porous drainage pavement system demonstrates significantly improved mechanical robustness and resistance to clogging compared to traditional pervious concrete. The hierarchical interception mechanism, comprising an upper wedge-shaped flow-guiding layer and a lower regular geometric seepage layer, effectively enhances the self-purification capability of the structure, offering a promising solution for sustainable urban drainage infrastructure.