Concrete type?

[ab12]

Did a soft fill in the cavity between engineers and inner block leaf consisting of 1 cement to 8 ballast after some google research.

 

Is this the right mix?

 

Know have done further research and the recommendations are to use 1:3:6 ratio of cement:sand: 20mm stone to make C10/M10/Gen1 (all 3 are equivalent) grade of concrete for the soft fill.

 

Is this equivalent to 1 cement:8 ballast? Also what is the ratio of sand to stone in ballast, cant seem to find the answer on the net.

 

Finally what type of read mix do I need for the floor please above sand blinding layer. Is it C20/Gen3/ST1 (all 3 are equivalent).?

 

Many thanks