White Residue on Stamped Concrete

[ssmorsi]

Good morning. I had stamped concrete poured in my back yard almost 1 year ago. I was told to wait at least 2 months before I sealed it to make sure it cured. After 2 months, we had really bad weather (hot, cold, windy) and I was unable to seal it. Now there is white residue and discoloration in the concrete. Is there hope for saving this concrete? Is there a way I could "clean" off the residue so I can seal it? When I hose it down, the original color shows through like new but of course it turns white again after it dries. That dark brown band you see is supposed to be all one color.

Thank you

 

[concretemasonry]

The white deposit is obviously efflorescence. There may also be a problem with dark pigment and method of application.

This is really not a concrete engineering problem because of the nature and wide variability of stamped concrete, the materials used and the methods of installation.

Dick

 

[hokie66]

To remove the efflorescence, I would try diluted hydrochloric acid, 1 part acid to 10 parts water. Leave it on for say 5 minutes, vigorously brush it, and hose off. If that doesn't work, there are other commercial acid preparations, try your local hardware or paint store.

 

[geocrete]

The best info I can give you on discoloration and possible repairs is this link:

http://www.nrmca.org/aboutconcrete/cips/23p.pdf

The NRMCA / PCA Concrete in Practice (CIP) series of publications are a good guide to help narrow down and resolve some of the most common concrete problems. references for further reading are at the end of each CIP.

Hope this helps

 

[concretemasonry]

Do you have any idea what kind of pigment was used? There can be different types, especially with the dark browns or blacks.

Dick