Project is to create a 3x3m concrete square to serve as a base for a ready to assemble pergola. So very light traffic, not much weight to bear (2xadults, 1xsofa, 1xbottle of gin, 1xbottle of tonic, 4xice cubes). Plan is to protect the concrete surface with a polyurethane paint after curing.
This 3m square is to be concreted over a previous shed base which was made of random size slabs (see pic). Slabs were laid (not very evenly) on a sand and soil substrate.
My plan would be to break the slabs in situ to serve as hardcore base, try to level and pack this hardcore base (with a sledgehammer) the best I can, prepare a frame around it and pour concrete.
1/ Any rule of thumb on how to level and pack the hardcore? What is the maximum size I should allow for the hardcore bits - as they have to be smashed down by hand?
2/ What would be a reasonable concrete thickness for such a light usage? Should I use a metal mesh to reinforce the slab or is it overkill?
3/ What kind of concrete mix is the easiest to do for a beginner? I have done a few postcrete and a slab for a bikeshed, but this was guesswork.
Thank you for your input and knowedge!