PSP (Metallic Panels)- Request your contrib

[ASIAN FROG]

I have a technical problem to solve on an airfield used 25 years ago by USAF. A tarmac is made with those metallic plates (PSP), the "PSP" are rusty but seem in workable condition for General aviation particularly a Flying School. I have seen on old photos that the Tarmac was black.
My questions are:
Has anybody information about maintenance of those PSPs? Have they to be painted and do we need any specific paint? What is the method used to take out the grass (Any specific chemical weed killer -compatibility with those iron plates?)
if we put a layer of concrete or asphalt what are the risks of cracks?
Any experience on utilisation and maintenance appreciated.
Thanks

[Kato747]

PSP or "Pierced Steel Planking" was never really meant to be painted. They were meant for providing a temporary stablized surface from which to operate until permanent tarmac could be installed. Unfortunately, application of a rust inhibitor on the surface won't solve future corrosion on the under-side.

IMHO, a layer of concrete or asphalt on top of the PSP could not hurt, but cracks would be inevitable at the joints (eventually).

Commercial weedkillers, such as "Round-UP" will not affect the surface, but will require manual removal of the dead vegetation.

Good luck with the project!