Line 1: |
Line 1: |
− | For advice on decorative surface aggregates see '''[[Stone]]'''
| + | Did you want an article on [[Reservoir gravel]] or [[choking layer|finer gravel]]? |
− | | |
− | *Granular material for underdrains should be clear crushed 20 or 50 mm diameter stone graded in accordance with [https://www.astm.org/Standards/D2940.htm ASTM D 2940],
| |
− | *The 20 mm clear crushed aggregate permits the use of an overlaid layer of high performance bedding (HPB) as a choker layer,
| |
− | *The void space ratio should be > 0.35 (or > 35%)
| |
− | | |
− | All gravel should meet the following criteria:
| |
− | *Maximum wash loss of 0.5%
| |
− | *Minimum durability index of 35
| |
− | *Maximum abrasion of 10% for 100 revolutions and maximum of 50% for 500 revolutions
| |
− | | |
− | [[Category:materials]]
| |