Clogging Processes Of Permeable Paver Systems

The pore structure of permeable paver systems can improve the water quality of stormwater through infiltration and adsorption.However,the voids of permeable layers are prone to clogging due to a large number of sediment particles or other contaminants over time,which largely attenuate the surface permeability of systems and affect their long-term hydrologic performances.Based on the laboratory experiment,the effects of different sediment concentrations(450mg/L and 650mg/L),sediment particle sizes(0-200?m,0-600?m and 0-10000?m)and maintenance methods(non-cleaning,vacuuming and pressure washing)on the clogging processes of permeable paver systems are tested.The results showed that:The infiltration rates decayed exponentially in permeable paver systems under different conditions(R2>0.94).The clogging processes of systems increase with sediment concentrations.After 11 years,the infiltration rates of systems at the concentration of 450mg/L were 264.7-377.6mm/h higher than that of systems at 650mg/L.The wider particle size range of sediments increase the possibility of the clogging processes of systems under non-cleaning and vacuuming.After 15 years,the average infiltration rates of systems decreased to 241.6mm/h and 98.0mm/h at the particle size range of 0-200?m and 0-600?m.While the infiltration rates of systems at the particle size range of 0-1 000?m decreased to 26.0mm/h after 7 years.Pressure washing can push the finer particles into pore spaces or lower layers and accelerate the clogging processes of systems.The infiltration rates of permeable paver systems at the particle size range of 0-600?m was 140.6mm/h higher than that of 0-200?m after 10 years.The permeable paver layers,bedding layers and geotextiles have played important role in the vertical structures of permeable paver systems.The average infiltration rates of permeable pavers have reduced 93.3%,64.0%and 85.2%compared to new paver layers.The recovery effect of vacuuming was better than pressure washing on permeable paver layers.The average infiltration rates of old bedding layers and geotextiles have attenuated 69.8%,74.5%and 55.6%compared to new ones after the experiments.Fine particles less than 200?m in diameter carried by stormwater were mainly accumulated in the upper bedding layers,while the changes of lower bedding layers were not obvious.The contents of fine particles(<200?m)in the upper bedding layers increased 35.9%,12.9%and 29.4%compared with the new layers under different maintenance methods.The recovery effect of vacuuming was better than pressure washing,as the changes of finer particles in the upper bedding layers were the smallest.The average infiltration rate of permeable paver systems was 62.8%of the newly installed systems after the replacement of old bedding layer and geotextiles,which significantly higher than the"new paver+old bedding layer+old geotextile" systems.Therefore,the replacement of bedding layers and geotextiles can obtain better recovery effects of permeability than paver layers in permeable paver systems.