Hi there,
For something that size you may find it more cost effective to just order ready mix concrete. It saves a lot of time, energy and labour, and pretty much guarantees u will get the best, strongest concrete consistency for the whole job.
Mixing that much by hand/mixer unless u have a team of people to help u could be quite difficult. Not only because of the hard work which is fine, but while someone is on the mixer u will need someone spreading and levelling/tamping the concrete, also putting that many mixes in one after the other some people may miscount the amount of cement they have used. Doesn't answer the question of how many tonne bags etc, but something I would personally do.

Hi
You be looking for 40 ton bags of ballast and 200 bags of cement .
Best Michael

There is a company called mixit,
Thay are a little more expensive per ton but thay mix on site to the nearest barrow full.
This in turn means no waist or if a little short on messure it dont matter.
Thay also supply extra wheelbarrows to get it done.
For little more cost for long distance thay will supply a pump with two men and the driver whome help with the lay.
Thay also clean up behind them selfs and the job is complete in a fantastic time leaving less chance of it crack.
Ive always found thay concrete to be of a high standard and thay can give you what ever strength needed or diffrent water consistency..
Ready mix are good if your messure is perfect or you over order a little.
You need somewhere to put the surplus and to let let the lorry wash out.
Mixit takes all these factors away.
Hope this helps

Regards

Terry

For this amount you would definitely be better off getting ready mix concrete. Its best to shop around as local concrete companies can greatly vary in price.
Also for an area of that size don't forget to include expansion joints.

Hello yes u need to install a sub base of chrushed concrete first then install gravel driveway on top