Ballast and cement

[BigG1979]

HI
Im planning to extend my concrete slab for a new shed and have a few questions.
The size of the new slab is 2.2m*2.6m * 130mm deep which i think is 0.75m3

1) How much ballast and cement bags do i need to buy? Was planning to buy 40 ballast and 10 cement
2) Do i need to leave a space between the new slab and the old one?

Really appreciate any advice

 

[PrenticeBoyofDerry]

1) This should do it

10 Cement 25 Kg Bags
Ballast (all in) 1.24 Tonnes

online calculator

2) no.
It would be handy if you could tie them in together by using metal pins but if it's only a shed not critical, but wouldn't leave a gap.