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| ===Foundation aggregates=== | | ===Foundation aggregates=== |
| [[File:Geogitter-4.jpg|thumb|Geogrids like these are sometimes incorporated into the layers of permeable pavement foundation aggregates to provide additional stability and conserve aggregate material]] | | [[File:Geogitter-4.jpg|thumb|Geogrids like these are sometimes incorporated into the layers of permeable pavement foundation aggregates to provide additional stability and conserve aggregate material]] |
− | Most [[OPSS aggregates]] are not recommended for use in permeable paving systems. The exception being type 'o' with a default void ratio of 0.3. | + | All aggregates should meet the following criteria: |
− | *[[Choker layer]]
| + | * Porosity of 0.4 |
− | *[[Reservoir aggregate]]
| + | * Maximum wash loss of 0.5% |
| + | * Minimum durability index of 35 |
| + | * Maximum abrasion of 10% for 100 revolutions and maximum 50% for 500 revolutions |
| + | Most [[OPSS aggregates]] are not recommended for use in permeable pavements, with the exception of 'Granular O' type. |
| + | |
| + | '''<u>Granular Subbase</u>''' |
| + | Should be clear, crushed 50 mm diameter stone, graded in accordance with ASTM D2940. |
| + | <u>'Rain ballast' aggregate (63 mm) would also be suitable</u> |
| + | |
| + | '''<u>Granular Base</u>''' |
| + | Should be clear, crushed 20 mm diameter stone conforming to ASTM C33 No 57 |
| + | |
| + | '''<u>Bedding</u>''' |
| + | Should be clear, crushed 5 mm diameter stone, graded in accordance with ASTM C33 No 8, High Performance Bedding (1-9 mm diameter), or equivalent. Typical bedding thickness is between 40 mm and 75 mm. |
| + | |
| + | For more information, also see [[Aggregates]] page. |
| | | |
| ===Geotextile=== | | ===Geotextile=== |