Numerical and experimental investigation of void clogging removal in porous asphalt pavements

Porous asphalt pavements are designed to drain water quickly, but their performance drops as sediment clogs the voids over time. This study investigates how clogging occurs and how different cleaning methods restore permeability, using CT scans, CFD-DEM simulations, and lab tests. Results show that clogging behaviour depends on particle size and source: gravity mainly affects particles under 2.36 mm, traffic pushes larger particles (up to 4.75 mm) deeper into the pavement, and rainfall carries fine particles below 1.18 mm into lower layers. High-pressure water jetting cleans more deeply than suction, restoring over 70% permeability, though it can drive particles further into the structure. The best cleaning was achieved by combining 20 MPa jetting with negative pressure suction. Cleaning performance did not improve significantly beyond 10 MPa, pointing to a pressure limit. Pavements with higher void ratios were easier to clean but more sensitive to damage. The results show that choosing the right cleaning method based on the pavement’s void ratio can improve results and reduce damage: 10 MPa water jetting works well for pavements with 15% void ratio, 20 MPa for 20%, and combining 20 MPa jetting with suction is best for 25%. The study contributes to optimizing maintenance protocols and extending the service life of permeable pavement systems in sustainable urban environments.