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Line 79:
Line 79: − + − *[[Choker layer]]+ − *[[Reservoir aggregate]]+ + + + + + + + + + + + + + + +
→Foundation aggregates
===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:
* Porosity of 0.4
* 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===