Concrete base for prefabricated garage help needed quickly!

Just recently had a concrete base laid for a prefabricated garage. All looked fine to start with, hardcore decent depth etc my first concern was running out of redimix but off they went and mix'd up thier own, finish looked fine little rough but overall looked fine.
unfourtunatly it wasnt covered and about 36 hours later we had a frost.
Its now been 4 1/2 days, seems fine to walk on but was concerned if the base may have been damaged by the frost? the garage arrivews in about a week and is going tobe mighty heavy I expect and dont want to realize after that ~I have issues.

What problems can the frost have caused? what is it likely to have done? and how can I check or do anything about it?

many thanks all

a 36 hour delay with the frost means that the concrete will be unscathed.

drying time may be prolonged but this will only benefit.

Right the garage is due to be erected on Tuesday - 4 days time and still concerned about the base, one patch in the middle (not so important as there will be no weight there) and at the front the top 1mm of concrete has lifted in flakes, looks like a stiff brush would remove them and underneath looks fine is this a concern? or just result of light frost damage and nothing to worry about?
On close inspection it does seem like a fingernail can just about mark the surface, although not sure if thats normal and now I'm just being paranoid...

I must admit its been very cold down here and been frost every morning, anything I can help with? electric blanket? anything to stop me panicking would be good!
can allways add a photo or two if it will help

I'm really no expert but laying some insulation over the concrete could help.

May be an unnessesary expense to use the proper roof stuff but some cardboard packing, polystyrene, bubble wrap may do the job.

Alternatively wollies are probably nearly giving away duvets at the moment.]

Of course this only works if the ground is above freezing most of the time. If its below you need some way of heating the concrete, and I can't imagine how one would do that!

The soft spots on the surface will be due to changes in temperature, the concrete giving off heat as it cures evaporates and with the frost on top it creates a slurry as such on the surface. It’s not really a problem apart from aesthetically and the only way to stop it would of been to have a constant temperature. I take it you didn’t insulate the underside of the concrete raft with it being just a garage of have a large tent and heater available!.

Structurally without knowing specifications you can't say whether it will be strong enough, i would'nt worry about it failing due to the frost unless there was extreme changes in temperature, average garage 200mm slab? Couple of layers a393 or similar mesh?, 300mm well compacted hardcore on good ground would be more than enough.

Maybe it would be an idea to use a couple of mm of self levelling concrete or a screed mix once the garage is installed if your not happy with the finish.

fantastic just what I was hoping to hear, 4" of hardvore then 4-6" of concrete(redimix) with mesh, should be fine then, been really cold here and in places it dosnt look like its set much at all but its been frosted for 7 solid days, heavilly wrapped up atm so hopefully should help now, best to unwrap during daylight hours or keep wrapped up?

If you are capable of doing a good trowelled finish I would lay about 20mm granolithic concrete inside after the garage is built.(1/4"to dust grano aggregate 5-1 with cement) This will prevent water ingress under the garage walls and when well dried (allow 28days) paint with floor paint to stop dust.