PAV2 mix - when okay to drive on

[GJUK]

Hi guys,

I've poured a 8mx1mx70mm ramp to a garage 6 days ago. at 5*C
With the weather being just above freezing, this has been covered well day and night for the duration.

The mix is a PAV2 mix from Breedon and had no water added.

Would it be okay at this stage to start using the ramp - they're advising 28 days for full strangth. But being nearly a week am I okay?

Thanks,

Jon

 

[JohnD]

concrete cures much more slowly in cold temperatures, so you would risk damage of scuffing or cracking if you try to use it earlier. 10C or below is cold, for concrete. There are tables somewhere of days per temperature.

A week in summer would be cured better than a week near freezing.

You will get a slight gain by damping it with hot tapwater from a watering can each evening before you replace the covers (it must not dry out or hardening will stop)

IMO you can get an idea of the curing progress by scratching an unobtrusive surface. If your thumbnail will scratch it, it's soft. If a teaspoon will scratch it, it's soft. If you need the sharp point of a steel nail, it's doing well.

 

[GJUK]

Thanks.

I read that adding water can cause issues if it gets cold?

It been covered the whole time and it is still soft - you can scratch it with blunt metal at the moment.
Kind of wanted to get my cars in to the new garage and didnt want it to crack. Perhaps if I brace it with thick ply along the top and drive over that it will be okay and not damage the structure?

Thanks

 

[JohnD]

PAV2 is a strong mix, so presumably you've paid extra for a strong ramp.

It would be sad to damage it before it's properly cured. I fear it will be marked if you drive on it, and may well crack at the edges.

Try to curb your eagerness.

A mild week, with constant drizzle, is just what it needs. Wetting it now that it's set is just to prevent it drying out, especially on the surface, which you want to cure well to resist traffic wear. Once it dries, hardening stops (permanently).

 

[GJUK]

I'll add some water to it tonight and wait a bit longer to get in there!

Thanks