Improving Restorative Maintenance Practices for Mature Permeable Interlocking Concrete Pavements

Permeable Interlocking Concrete Pavements (PICP) are a Low Impact Development (LID) technology that reduce the total volume of stormwater discharge and peak flows from urban hardscapes. Over time, particulates accumulate in the PICP joints, decreasing the pavement’s surface infiltration capacity and negatively affecting its overall functionality. Maintenance with two surface treatment technologies, a hand-held power brush and pressure washer-used in combination with vacuum street sweepers were compared to maintenance with vacuum street sweepers alone at four PICP parking lots. Both surface treatments along with vacuum street sweeping significantly improved the restoration of infiltration capacity for the young (i.e., <4 years) PICP section. Pressure washing in combination with vacuum sweeping was effective for PICP sections with larger (13–14 mm) joint openings. Power brushing, however, provided inconsistent results between the PICP sections. The effect of surface treatments was not significant for older (i.e., >6 years) installations with small (3–4 mm) joint openings. Though surface treatment resulted in significant improvement with a pressure washer and vacuum street sweeper combination, usage intensity of the parking lot was deemed as an important factor in restoring infiltration capacity. These findings re-emphasize that regular maintenance is essential to ensure long-term hydraulic functionality of PICP