30 Minute Presentation
Permeable Interlocking Concrete Pavement Maintenance Update
Increased stormwater runoff from impervious surfaces cause a variety of environmental problems including flood damage, stream channel erosion, decreased groundwater recharge, and water quality degradation, particularly near urban areas. The use of Permeable Interlocking Concrete Pavement (PICP) as a parking lot or roadway and a stormwater control measure (SCM), all in one system, has proven to be a viable solution. PICP systems allow rainwater to flow directly through a pavement surface into an underlying stone reservoir before infiltrating into the subgrade soil and/or discharged through a drainage outlet pipe. These SCM systems are capable of meeting regulatory stormwater requirements for runoff control, stormwater detention, and to reduce pollutant levels and peak flows.
The use of PICP continues to grow throughout North America. Land developers looking to incorporate green infrastructure solutions, or to overcome land use restrictions, have begun utilizing innovative design options instead of traditional stormwater detention basins, particularly where land costs are high. The benefits of using PICP are well documented after decades of use. These systems are effective at reducing runoff and surface flooding by providing underground aggregate detention. Water quality benefits through sediment capture and filtration are also well documented. Because PICP is designed for vehicular loading in parking lots and roadways, developers and municipalities can utilize needed pavement infrastructure to also manage stormwater.
Recently, much attention has focused on the required maintenance of permeable pavement. Because PICP collects sediment and debris within the permeable surface joints, surface infiltration rates decrease over time. This presentation will review how sediment accumulates on PICP, and the role joint opening configurations and filter aggregate gradation have on surface infiltration rates and ease of maintenance.
Routine maintenance ensures that even with a gradual reduction of infiltration rates over time, most rain events infiltrate though the permeable surface openings for the design life of the PICP system. The advantage PICP have over other detention and infiltration stormwater control measures is the accessibility and ease at which surface sediment material can be removed and joint filter aggregate replaced.
Contractors and pavement cleaning equipment suppliers have developed machinery and methods for restoring surface infiltration capabilities for a variety of permeable pavement systems. This presentation addresses the effectiveness of available commercial cleaning equipment options such as: mechanical sweepers, regenerative air cleaners, vacuums, and hybrid equipment that combines high-pressure air and vacuum methods.
The Interlocking Concrete Pavement Institute (ICPI) and the American Society of Civil Engineers (ASCE) Permeable Pavement Committee have developed guidelines for PICP maintenance. The presentation concludes with the latest information on the ICPI’s recent PICP research and recommendations for maintaining PICP.