Where Did The Color In My Concrete Go?
Here’s the situation. 18’x36′ concrete slab was poured on July 31, 2008. The pour was done by one truck(11 yards) and 5 gallons of liquid color was dumped into the concrete (4000) and was mixed for 15-20 minutes before it came off the truck at 8:00AM. The pour was done by 9:00AM and I covered it immediately with a tarp so the sun wouldn’t beat down on it so much and to give a little more working time. The slab got a smooth finish and was hit twice with the power trowel. Meaning it worked the slab from left to right and then immediately right to left and then then it went back on the truck———- Three days later the stain started to ‘fade’ away in certain areas. Small spider vein type patterns started to emerge in the areas where the color was solid and over a week or so the solid color went away.———- I went back to the place where the color was purchased and saw on the computer that it had been mixed on July 30th in the morning and I picked it up that afternoon. I recently talked to two people there and they had never heard of anything like this happening.———- I did not apply a sealer to this slab. And the deck frame was there prior to the pour. It did rain a day after the pour and I inquired if the chemicals in the PT lumber could have played a part in this. Everyone asked told me no.———- So my question to all of you BTer’s is… Have you ever heard of this happening? What could have caused this? Could the mix from the concrete plant be the culprit? If I apply a stain, what is the likely hood, if any, of this problem happening again?———- Thanks In Advance!————- The pour
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Finishing the slab
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The very next day
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3 days after the pour
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This is how the slab looks as of today(8-21-09)
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I do have more pictures but these should give you a general idea.
Replies
My experience is limited, but dyed concrete lightens considerably when it sets. How did you arrive at the amount of colorant to add? Was it by a color chart? The amount to use is based on the amount of cement in the mix, too, so that has to be taken into consideration when calculating the amount. I know I'm not being much help.
Some liquid dyes are not colorfast when it comes to UV exposure, but I can't see a concrete company who dies this on that type of scale screwing up just your mix, unless you requested a color that they don't normally use. And the slab is under cover, that should help with the UV.
Is some of that whiting efflorescence? That could be a culprit. Not sure though.
You could give it a good cleaning and see if that helps. If not, then maybe try an acid stain. Acid stains work best the greener the concrete is, but you should still be able to get good results as your slab seems to be in pretty good shape.
The dye isn't fading, the concrete is getting covered in efflorescence. I'm betting you poured on raw dirt and didn't put a poly vapor barrier underneith it and moisture is wicking up into the slab from below and evaporating out of it at the surface leaving the mineral content of the groundwater behind it as it leaves. Best solution would be to cover it with brick pavers. Sorry. If you placed a poly vapor barrier under the slab before you poured then I have egg on my face.
m
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((The dye isn't fading, the concrete is getting covered in efflorescence. I'm betting you poured on raw dirt and didn't put a poly vapor barrier underneith it and moisture is wicking up into the slab from below and evaporating out of it at the surface leaving the mineral content of the groundwater behind it as it leaves. Best solution would be to cover it with brick pavers. Sorry. If you placed a poly vapor barrier under the slab before you poured then I have egg on my face.
m))
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So it would take less than 3 days for efflorescence to occur?? I put 18 yards of 3/4" process down for the base of this 18'x36' slab and there was some nice material under that which drained quite well. You are correct in that poly was not used.
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I'd say it's more of the type of finishing method used.
Troweling leaves such a smooth full finish that the light reflected becomes more dominate. Power troweling limits one's success with a subsequent acid stain. I feel a brushed or broomed texture may have had better results.
And UV?, I had a slab poured inside, on top of another, colored as you describe, also fade to a practically unnoticable tint.
IF this was the end of your fanciness efforts, I'm sorry it didn't work better. But you still got a nice slab in good condition.
In my case, I retopped with a microtopping and stained it green to match the walls. Poor choice, the color didn't match. Next, I'm gonna grind off that micotopping and retop with a stamped wood plank pattern. I can stain that color with much better success.
<<<I'd say it's more of the type of finishing method used.Troweling leaves such a smooth full finish that the light reflected becomes more dominate. Power troweling limits one's success with a subsequent acid stain. I feel a brushed or broomed texture may have had better results.And UV?, I had a slab poured inside, on top of another, colored as you describe, also fade to a practically unnoticable tint. IF this was the end of your fanciness efforts, I'm sorry it didn't work better. But you still got a nice slab in good condition. >>>
peteshlagor, thanks for your input.
A smooth finish was desired as opposed to a broom finish. We wanted to use the space for entertaining, children to play, nice shady place to relax, etc. And with the thought of installing some type of under deck roofing system in the future so we could be out the when it's raining outside to further utilize the space.We're not done with our efforts to remedy the situation. I'm hoping someone will come along who has experienced my problem and has found a solution and cause of the problem.
As Brownbagg was alluding to earlier, a sealer will change the looks quick. but not an epoxy sealer. More like a two part ureathane mix. This will be more UV resistant and is commonly used as an epoxy sealing topcoat.
But I'd be doing a mild acid wash and light power wash (using a spinner) and maybe a deeper acid stain first. Note: the acid stain will give a verigated, mottled appearance, enhancing what you already got. (Avoid any attempt to swish or mix the acid while it's doing it's job. And then neutralize with bicarb before washing.) Keep the color light and matching another in the landscape. Then the sealer will knock 'em out. The second sealing coat should have very tiny particles of pumice or such to act as a slip resistance. She'll get reeeeaaal slippery without it when it gets wet.
Or a cementatious topcoat in the color or texture of your desire.
These commonly involve specialty commerical coatings although they're not out of the reach of the DIY'er. Just don't make the end results look like a DIY.
I hired a company that did patterned concrete to come and do their stuff on a new front door landing. I picked a colour (which he claimed was one of the most commonly chosen colours from his colour chart), and they mixed the dye into the top layers of the concrete as is was poured (the colour looked good at this point), which they subsequently stamped with the rubber forms. Same thing happened on my landing.. ie the colour never really showed up after drying. The installer kept telling me the colour would develop over 30 days or so, but in the end I ended up with a very very faded version of the original intended colour. The final colour did improve once they came back and did an acid wash of the entire surface. Perhaps you could inquire about the possibility of such a wash on your surface.
In my case the landing is up in the air ( ie no ground contact so no poly either)... so a lack of poly was certainly not the problem for me.
Edited 8/22/2009 7:34 am ET by Kivi
>> I hired a company that did patterned concrete to come and do their stuff on a new front door landing. I picked a colour (which he claimed was one of the most commonly chosen colours from his colour chart), and they mixed the dye into the top layers of the concrete as is was poured, which they subsequently stamped with the rubber forms. <<
When stamping concrete normally a colored, powdered release agent or "shake" is put on top of the concrete prior to stamping. This "shake" becomes somewhat imbedded in the to 1/4" or so of the surface. That, in combination with the concrete color gives the stamp job a bit of a 2 tone look and adds to the 'dimensional' look of the surface. After the work has cured for 24 hours they come back and saw cut where necessary and then gently powerwash it to get rid of the excess shake and the debris from the saw cutting. Once the surface water is dry, usually later in the day, a sealer is applied that enhances and seals in the color. This sealer has to be reapplied every year or 2. If it is not resealed, the color will suffer and start to fade.
Comments?
The way you imbeded those wide pics in pur post made it very hard to read. The text is wider than my 19" monitor.
I'll 2nd the poly under the slab but also say that I think it should have been sealed.
<<<The way you imbeded those wide pics in pur post made it very hard to read. The text is wider than my 19" monitor.I'll 2nd the poly under the slab but also say that I think it should have been sealed.>>>Sorry about that. I'm not all that computer literate so for me posting pics was a success. Everything fit on the screen of my 13'' MacBook so I thought it would be fine for everyone else?As for the sealer, I was told not to apply any with the hopes of the color coming back. If a sealer was applied it would greatly slow the process of the color coming back. Also, if a sealer had been applied, it would have to be removed in order to put down a stain.
Edited 8/22/2009 9:56 am ET by kltzycrpntr
10-4 on the stain. Was that in the initial plan?
Really I'm more experienced with stamped concrete than colored. I do know that I once parged a foundation with dyed mortar and left it raw. As time when on and on, the color got lighter.
Personally, I think whoever said that the color would get darker as your slab aged was blowing smoke... That's just my guess though. Concrete always gets lighter (whiter) as it cures for the first few months. So why wouldn't any color that is in there get lighter as the slab aged and turned white.
A few weeks ago I was told to patch a crack in concrete. At blows every concrete patch material they had - there was about 6 of them - was some shade of gray. Concrete is closer to off white when it is cured. I told them the patch material wouldn't match at all and sure enough....
Did brownbag comment on this? If not you should bump him.
Edited 8/22/2009 10:35 am ET by Matt
put a clear epoxy sealer on top of it and the color will pop back out
If the color pops when the slab is wet, I'd agree. But if he has moisture coming up through the slab from below, I wouldn't want to see him put an epoxy film sealer on top of the slab.
BB - quick Q - I have some front porches going in on a very muddy (red clay) construction site. Light broom finish. It will be difficult or impossible to keep the red clay off the concrete once it is placed, and I know that stuff doesn't power wash off very well. Will sealing the concrete immediately after it is placed help with this?
yes
I got this from a walkway that was poured on dirt. It set up too fast to stamp.
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It was poured maybe 5 years ago in 100° August weather. No fading or splotching... I don't think you had enough dye...
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