Land development in urban areas across America have resulted in excessive amounts of impervious pavements that cause stormwater problems. In urban areas, impervious surface area can cover a significant amount of drainage basins. The obvious solution to mitigating impervious surfaces is to create pervious surfaces. Society needs pavement surfaces, but in many construction and redevelopment projects, designers and government officials should consider permeable pavements as part of a green infrastructure strategy. Permeable pavements are considered green infrastructure because the permeable pavement surfaces can mimic the natural stormwater infiltration of undeveloped land surfaces.
Stormwater professionals that want to utilize permeable pavement have a selection of different materials and product options. The most common and well-established permeable pavement systems include: pervious asphalt, porous concrete, and permeable interlocking concrete pavement (PICP). However, there are also innovative alternative materials that can function as a permeable pavement.
Permeable interlocking concrete pavement (PICP) systems have enlarged spacer bars that create surface openings that are filled with highly permeable filter aggregate. Typically, PICP has between 5–15 percent surface openings that are often between ¼ inch and ½ inch wide and are always filled with open-graded washed angular aggregate stone. The size of the infill stone is based on the joint width and is either specified ASTM No. 8, 89, or 9 stone. Even though the surface only has 5–15 percent openings, it is 100 percent pervious because the flow rate is so high between the joints.
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1. Explain how permeable interlocking concrete pavement can provide stormwater management benefits to land development projects.
2. Describe proper specifications for construction of PICP systems.
3. Explore the industry recommendations for maintenance of PICP systems.
5. Identify industry resources for specifying and designing PICP systems.