Advice needed onsub-base under new gravel driveway - New gravel driveway

[tinajeromegardendesign]

Hello,
Could anybody help me please. I am a new Garden Designer (so not much experience in this topic) who has my 1st client who would like a Vehicular Driveway to be constructed from Gravel. The client currently has a tarmac driveway, and I want to re-use / re-cycle the old tarmac driveway as part of the Sub-base, mixed with other old paving from around the garden, (trying to be environmentally friendly and keep costs down). I know that ideally the Sub-base should be 75-105mm of DTp1 then 25-40mm gravel on the top, but was wandering if I could use the old tarmac drive as a sub-base? - Would it be strong enough to withhold vehicular traffic? Any advice for a Newbie would be much appreciated!!
Thank you!

[Pablo]

honestly it would be cheaper to rip it out and lay fresh stone. The stone should be 150mm deep otherwise the cars will chew it up in no time. The waste you produce is likely to be recycled by the skip company so thats that box ticked to. The only way to turn all that bitmac and rubble into anything usable is with a crusher and it'll still need blinding with type 1 so the gravel doesn't mix to readily. It's also likely to make a very poor base.

[lutonlagerlout]

we just did a similar drive and the tarmac was taken away separately for recycling
as pablo said 150mm of wacked type1 and 50mm of 20 mm shingle also wacked is working fine
we did a 900mm crossover to stop gravel migrating on to the highway
LLL

[tinajeromegardendesign]

Thats great! Thank you so much for your expert advice....Much appreciated!

Tina.