Without a separator, traffic pushes stone down into soft soil and pumps fines up into the stone, so the base loses thickness, strength and drainage. A geotextile between the layers keeps both intact while letting water pass. Separation is the most common geotextile function on roads, rail beds, parking areas and laydown yards.
That base was 12 inches when we built it and now it's mud, no separation fabric, the stone just disappeared.
Also heard as
- separator
- separation function
Related terms
Geotextile
Permeable fabric used with soil to separate, filter, drain, reinforce or protect, made woven, nonwoven or knitted.
Subgrade
Native or prepared soil surface on which a pavement, aggregate base or liner system is built.
Stabilization
Improving how soft ground or an aggregate base carries traffic by adding geogrids or geotextiles.
Pumping
Fines from a wet subgrade being forced up into the aggregate base by repeated traffic loads.