I mistakenly applied a patio cleaner containing acetic acid to my porous concrete facing brick thinking it was biocide. The concentrate solution has a ph of 3 and I diluted it to one part concentrate and three parts water. About three hours later, having realised my mistake, I flushed it with water. I repeated this process the following morning and also on the morning after that. The bricks now appear to be dry. I have been told that the pore structure of the type of bricks I have is vital in protecting them from frost attack. I’m very concerned that the acid has damaged the brick and mortar joints and am wondering if the acid has now completely evaporated - one day after the last rinse. Is there anything more I can do to neutralise any residual acid? I would be very grateful for any information. Thank you.
Per Wikipedia on Fired Bricks, to quote their composition;
Normally, bricks contain the following ingredients:
Silica (sand) – 50% to 60% by weight
Alumina (clay) – 20% to 30% by weight
Lime – 2 to 5% by weight
Iron oxide – ≤ 7% by weight
Magnesia – less than 1% by weight
I would expect slowly, with time, that the acetic acid could attack all of the above with the exception of Silica.
Flushing with water would reduce the magnitude of the attack, but I would not categorically claim that the brick structure is completely sound.