Marks on concrete paving - Help!

[mouldmaker]

We've manufactured some bespoke paving for a prestige project (flagship store for am american retail chain).

They're 1m square with a flat polished surface. Nothing fancy about the mix, the client wants an 'industrial' look.

They were stored and transported with polystyrene strips between faces and have now been laid.

The problem: where the poly strips were, there are now lighter marks. The client will be sealing them this week with HG impregnator which I suspect will hold the mark there forever.

Any suggestions as to how I can make this go away, pronto? Polishing/grinding faces in situ is, apparently, not an option.

Mike



Edited By mouldmaker on 1253113666

[mickg]

ah seeing as you have edited it from darker marks to lighter marks one can now assume that the polystyrene strip has possibly sucked some of the moisture from the flag hence leaving a lighter colour when the flags were squashed tightly together during transportation,

I wonder is that why flag manufacturers use brown paper to space the products apart, one so the flags don't rub the face against each other and get damaged and the other so there are no pressure marks ?

I have seen it the other way round when flags are spaced apart with a thin strip of timber what leaves a darker mark on the surface but this normally disappears when you lay the flags, and is more than likely due to being stored outside in the merchants yard and the wood has absorbed rain water what has been transfered to the face of the flag which is something totally different to the problem your seeing

[mouldmaker]

So far tried a scrubbing brush, bleack and various concentrations of Brick acid. Even with the top surface quite drastically eaten by acid, the bloody marks are still there. Bugger.

[TheVictorianCobbleCo]

MMM, my prob wasn't exactly the same but you might need to hear this before proceeding. I did some white specialist slabs for a client, and the project mgr had cocked up the timing, which meant laying the slabs within a month of casting. A moisture content in the slab of above 5% means there WILL be damp patches appearing after laying, and therefore to seal the slabs before they are below that moisture content, is going to give you hassles. (Unless the sealant "breathes", and I've lost faith in the "specialists" - SO, I also recommend that your best approach is to leave them to settle over as long a period as possible - depending on the base - months!!! Don't be forced into trying to cover the marks!!