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Peteraxel29 Feb 2024 17:32Hi, the joints of the paving slabs in the entrance area were partially washed out and have been renewed. Fugli paving joint mortar was used, but the work was done poorly. It appears that while sweeping in the mortar, a wet broom was wiped over the concrete stones in some areas.
Now, after a few days and even after rain, the paving slabs show gray-white discolorations, partly covering large areas. Washing with water did not change anything.
What can be done, and which cleaner should be used? Thanks for your help.
Now, after a few days and even after rain, the paving slabs show gray-white discolorations, partly covering large areas. Washing with water did not change anything.
What can be done, and which cleaner should be used? Thanks for your help.
Hello questioner.
Some issues, probably including the one you mentioned, cannot be answered with 100% certainty.
My suggestion, based on the background you described, would be to remove the discolorations, which are likely cement and lime residues, using an acidic cleaning agent.
You can go out and buy appropriate cleaning additives after some searching.
I recommend conducting a so-called "field test," which is simple, quick, and inexpensive.
No joke: please use regular COLA for this. Apply it to the (dry) entire surface of one tile at the edge first, gently agitate the coated surface in circular motions with soft bristles (e.g., a hand brush), and let it sit for 3 or 4 hours.
Then rinse with clean water.
The suggestion to use COLA is sincere!
Cola contains a significant amount of phosphoric acid, which, although having a pH of about 1, is a triprotic acid only weakly acidic overall.
If the tile’s surface still shows some imperfections after cleaning but looks visibly improved, repeat the procedure, possibly extending the application time.
Good luck: KlaRa
Some issues, probably including the one you mentioned, cannot be answered with 100% certainty.
My suggestion, based on the background you described, would be to remove the discolorations, which are likely cement and lime residues, using an acidic cleaning agent.
You can go out and buy appropriate cleaning additives after some searching.
I recommend conducting a so-called "field test," which is simple, quick, and inexpensive.
No joke: please use regular COLA for this. Apply it to the (dry) entire surface of one tile at the edge first, gently agitate the coated surface in circular motions with soft bristles (e.g., a hand brush), and let it sit for 3 or 4 hours.
Then rinse with clean water.
The suggestion to use COLA is sincere!
Cola contains a significant amount of phosphoric acid, which, although having a pH of about 1, is a triprotic acid only weakly acidic overall.
If the tile’s surface still shows some imperfections after cleaning but looks visibly improved, repeat the procedure, possibly extending the application time.
Good luck: KlaRa
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Peteraxel29 Feb 2024 19:12Hello and thank you for your response. Acid-based cleaner... hmm, I have read that concrete slabs are not resistant to acids. Or is that not correct?
Yes, that’s correct.
But we are not working here with concentrated hydrochloric acid (just kidding), but with phosphoric acid.
It is also an ingredient in many "cement residue removers."
Nothing happens; there is no chemical reaction between the acid and the alkali in the cement (or rather, it is lime).
But we are not working here with concentrated hydrochloric acid (just kidding), but with phosphoric acid.
It is also an ingredient in many "cement residue removers."
Nothing happens; there is no chemical reaction between the acid and the alkali in the cement (or rather, it is lime).
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Peteraxel29 Feb 2024 19:52Okay, I will try using cola. If that doesn’t work, Lithofin offers some cleaners. Which one would be suitable?
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