Tarmac tennis court - Flaking acrylic paint

[Zaika]

Hello.
A local school had a new bitmac tennis court laid at the end of Spring; the surface course was 0/6mm open bitmac. Two days following laying, the surface was spray-painted with green acrylic paint on the court itself. Grey acrylic was sprayed around the perimeter. The paints were water-based acrylic (allegedly).
After one month, the paint appeared to have shrunk and cracked in a leaf-like pattern. Where cracked, the outer edges had curled up and the paint film had detatched, lifting the surface from off the underlying bitmac. A black coating was on the surface of the acrylic and appeared to be some sort of mould or algae. Areas which had received a double coating, i.e., the perimeter strip and spray-pattern overlaps, appeared to be affected less.
There is no problem with unpainted tarmac.
The court has since been resurfaced, and appears to be OK (fingers crossed).
Logic points to the paint - but acrylic is recommended for this type of surface and use.
I would appreciate it if anyone could give me an idea what the cause of the failure may be. Would temperature/wet conditions affect the paint in this way?
Thank you.

[Tony McC]

You need someone from the paint manufacturer to assess the problem. We can't see it, and we don't know the product involved, so there's not much we can say.

[Zaika]

Thank you for that - I will certainly get in touch with a paint specialist.

I guessed that may be the route to take, but posted the query here in case anyone else had experienced similar problems.

This is a great forum, and I have learned many things from viewing other people's problems/queries.

Thanks again.

[TarmacLady]

When I was in the tarmac business, we never, ever recommended painting over fresh tarmac -- the volatiles have to have time to evaporate -- and three days isn't enough time.

The volatiles came to the surface and lifted the acrylic paint -- which allowed water to collect between the tarmac and the paint, leading to mould, mildew and various other nasties. Now that the acrylic is loose, it's very susceptible to expansion and contraction cycles with the very warm weather (and rain) that you've had this summer -- so as soon as it cracks, the edges dry up and curl, which lets even more water in, and so the cycle continues.

There IS an actual tennis court paint made -- not sure of the suppliers over there -- but coating green tarmac will always present a problem. Any coating you use will have to be solvent-based so as to not run amok of the volatile oil evaporation issue.

In the US, they don't even recommend coating fresh black bitmac with black coating until it's weathered for an entire year (because even though it's asphalt-based, the coating still has an ugly tendency to alligator and peel up).