Is all in ballast ok for a concrete floor?

[cascas]

Is all in ballast ok for a concrete floor. The floor is being raised in a hallway.

Part is being raised by 130mm to bring it to level with the rest of the hall, then a 50mm layer is required over the entire area. Is ballast ok for this (trowelled to smooth).

 

[noseall]

Use ballast/sharp sand mix (all in) for the raising up bit, then sharp sand for the 50mm screed.

 

[r896neo]

don't trowel it smooth if your screeding over it.