Pervious Concrete

• Reduces impermeable surface, thereby increasing water infiltration
• Reduces peak sewer discharge during storm events
• Reduces likelihood of ponding and slick or icy conditions
• Helps reduce urban heat island effect

• Extra care must be taken where there is water-sensitive sub-surface infrastructure
• Only certain soil types are appropriate as sub-bases for infiltration
• Porosity of the concrete can convey harmful chemicals into the soil
• Sand and certain chemical de-icers should not be applied to surface
• Contractors should be certified to install cast-in-place pervious concrete
• Slump and air content tests are not applicable to pervious concrete
• Lower strength material than standard concrete

• Pervious concrete is a pilot material that the city is testing at select locations
• Use of this material beyond the city-led pilots will require a maintenance agreement
• Most effective on slopes less than 5%
• Must have adequate sub-surface conditions to detain stormwater and level bottom to allow for uniform infiltration
• Avoid sites with frequent heavy vehicle traffic
• Avoid sites where there is potential for soil and groundwater contamination
• Not recommended for implementation over significant underground utility corridors

No specification source

See design guidance for Unpigmented Concrete
 

• Typically an 8- to 24-inch open graded stone infiltration bed is recommended
• Generally 4 – 8 inches thick
• Pervious concrete should maintain a 15 – 25% void content ratio
• Bottom of infiltration bed should be at least 2 feet above high water table and 2 feet above bedrock

• Requires routine vacuuming of surface using a regenerative air sweeper to restore permeability, which typically requires a maintenance partner

Rego Park, Queens