Influence of stratigraphy and slope on the drainage capacity of permeable pavements: laboratory results

A small size laboratory test-bed has been realized at the University of Genoa in order to evaluate the drainage capacity of permeable pavements by monitoring inflow, runoff and subsurface outflow. The laboratory test programme has been designed in order to investigate the influence of the rainfall intensity and pavement slope on the hydrologic response of permeable pavements. Four permeable pavement systems realized combining two paver typologies (concrete cell and pervious brick) with two filter layers made of recycled glass aggregate and a mix of gravel and coarse sand are tested. The hydrologic response of permeable pavements is analysed by using a dimensionless volume index (discharge coefficient) and a timing index. Laboratory results reveal that the hydrologic performance is fairly consistent for all the investigated permeable pavements. The recycled glass aggregate turns out to be a valid solution. No surface runoff occurs even at 98 mm/h rainfall intensity.