New concrete driveway "curing stain" w/pic...

[loutent]

Last week we had a new driveway poured and to protect the fresh concrete from freezing, the workers tarped it with insulated covers. Well when uncovered the next day we had staining which I have come to learn is pretty common when tarping is used and is known as "curing stain" which is caused by the concrete not curing equally because of condensation under the tarps etc.

I would be interested to know if anyone here has had this happen and what was done to correct it. I have researched a little and found that vinegar (or weak hydrochloric acid) may get rid of the stain. Some say leave it be and "acid rain" will take care of it eventually.

Any input appreciated - here's a pic:

 

[Rule3]

What did the concrete guys say?

I am no expert but concrete takes a long time to fully cure. I would do nothing.

 

[XDfense]

This happened to a neighbor of mine and looks just like yours. They did nothing to it and over a couple years time, it fixed itself.

 

[arjay]

Just let it cure.It will fade.

 

[Big Fred]

When I had a concrete pad poured outside my garage the mason told me to coat it with linseal. I used a sprayer and sprayed it and it looked like ****. Some places it soaked in and some places it stayed on top. I sprayed it even tooo. Anyway after a summer of sun it all matched and looked good. Here's hoping yours will all match after the summer sun bleaches it out.

 

[novalty]

Get yourself a Detroit diesel to park on your driveway, after a week you won't even notice the current stains.

A less subtle way would be to get some concrete stain and stain the entire driveway. They offer in blue and off white--can think of a nice symbols that would make you the envy of the forum--neighbors...not so much.

 

[Rule3]

Concrete needs to fully cure before you go putting stains, sealers or paint on it.

Again, contact the people who poured it. Depends on temp, moisture, additives etc etc.

http://www.tkproduct.com/Curing Concrete.PDF

 

[mtelkhntr]

For oil or rust stains on cured cement, I've taken powdered portland cement and broomed it in. It helps a lot but isn't a complete cure.

 

[forresth]

Why, oh why, are people always pouring concrete when they feel like it instead of when would be best for the concrete?

would waiting till warmer weather have been that horrible?

 

[Packard]

Muriatic acid is pretty much standard for cleaning concrete. But I would wait until spring to do any thing. UV light is a powerful bleaching agent over time--and the sun puts out prodigious amounts of UV. Wait a while.

 

[Maximumbob54]

I have to agree with Foresth. Bad time to pour it and it takes a month for it to actually be "mostly" cured in optimal conditions which the cold is not one. There are additives that aren't cheap to make the mix self heating to help in the cold but I doubt they used them unless you asked them to add something. I hope they poured the apron with high strength or that will be the first to start cracking.

 

[charlie sherrill]

Ask us this question again next summer.

 

[hannstv]

Unless it was something in the tarp itself, it will all fade out. Bright sunshine will even the coloring. If poured on a wet sub-base it will sometimes take a long time. Concrete poured in cooler weather usually becomes stronger than concrete poured in hot weather. Slower curing vs. flash curing.

 

[jdh]

Showed the pic to my concrete guy. "Leave it alone. Everything you do to try to fix it will make it worse. Especially with the broomed finish."

 

[Hillbilly77]

Get yourself a Detroit diesel to park on your driveway, after a week you won't even notice the current stains.

It wouldn't be a Detroit if it didn't leak at least a little bit.
Besides, Detroits don't leak - they mark their territory.

 

[loutent]

Showed the pic to my concrete guy. "Leave it alone. Everything you do to try to fix it will make it worse. Especially with the broomed finish."

I think that's the general consensus.

We had the driveway poured now because generally it's not that cold around here until dec-jan. It just happened that we had a couple of nights where the low temp could have dipped below freezing (hasn't happened since) and they wanted to cover it just in case.

The concrete company is well established & reputable so I figure they know what they are doing - we'll see what they say - probably leave it alone. Haven't driven on it yet - waiting for a good 7 days of curing - maybe more - we had it poured 6" with 4000psi, 5 inch slump w/wire and fiber. This is our 3rd driveway in 25 years and we want it to be the last.

Thanks for all the comments.