Originally Posted by Red Four
If you have PFC can you then groove the runway, or does it need to be re-surfaced in something else before/whilst grooving?
No, I don't think you can. I think if you tried to cut grooves in PFC you'd break the surface up. Anyway, the grooves would probably stop the PFC doing its job as designed.
Having worked with both surfaces over the years, in the long term I think that the better surface is the grooved Marshall asphalt. PFC works well when new, but does tend to break up badly in later life, causing operational problems as well as maintenance issues. It does of course get clogged up with rubber, as do the grooves, but grooves can be cleaned out. Also, PFC is a bit of a nightmare in the Winter. Potentially, if you get moisture in the pores and it freezes, it will blow the surface, whereas ice in grooves not only doesn't damage the surface, it doesn't reduce the friction much, either!
It's standard procedure to lay the Marshall asphalt first, leave it for a few days to 'go off', then cut the grooves. The problem with this is you have a potentially slippery surface if it rains before the grooves get cut. Asphalt is notorious for 'sweating' oils through the surface when it's newly laid.
Cheers,
The Odd One