ᐅ Concrete slab poured – How to identify potential frost damage?

Hello,
this is just a possible defect. I hope this is the right section for it.

We are currently building. The foundation slab was poured last week. Then frost set in. Temperatures dropped to minus 7°C (19°F). Apparently, the concrete was mixed with cement that has a higher heat of hydration. It was also supposedly covered. However, the tarp partially blew away in the wind.

So my question is: How can I identify any damage to the slab?

At deep, possibly wide cracks.

But only after drying.
Small shrinkage cracks, I believe up to 3 mm (0.12 inches) deep, are acceptable; more detailed information can be found in the respective DIN standard.