Just read this on another site
Very confusing
Will try and explain to you.
There are in the region of 7 Geo-Synthetic products on the market.
Of these you are only interested in Geo-textile, of which there are four number.
Woven, non woven, knitted and the rubbish that the sheds sell for weed suppression.
Of these four, the one that you may require is woven textile, how ever you only need a textile under your sub base if you are laying a heavy duty carriage way, or if after excavation, you find the sub ground has a clay content, is dampish and a little on the soft side. Then lay a woven textile. Will take us to long to describe the principles of how a textile works, but basically they keep sub bases from mixing into sub grades and vice versa, minimise and help to prevent soil-pumping, and act as reinforcement to sub grade and sub base.
Wearing course, call it what you like. Stone, gravel, shingle or aggregate. Clean graded with no fines, round or angular or self binding with the addition of fines Your choice.
Textile is a separating layer to separate two materials, and if you lay a clean graded aggregate on to textile on top of sub base every time you drive over wearing course you are slightly moving aggregate back and forth and in a very short time will disintegrate the textile below the wheel tracks. Should you have a wheel spin, then you will go through the aggregate and rip the textile up as easily as tearing toilet paper, and leave ragged edges of textile above the aggregate.
Suggest. Aggregate of your choice. 30 to 35mm thick. Graded 20mm down to 10mm. Spread half of thickness and run two passes of plate over to slightly bed aggregate into sub base, spread remainder and rake to levels required.
An edging is very beneficial to retain aggregate.
Regards oldun