10 Month Old Concrete Driveway Spalling/Flaking

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Old 05-27-09, 06:26 PM
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10 Month Old Concrete Driveway Spalling/Flaking

Last July, our developer had installed a new concrete driveway at our house and I had sealed the driveway about a month after. As luck would have it, we had a terrible winter. However after the snow melted away we realized that the cement began to flake badly.

- Could de-icing salts used over the winter have caused the driveway to prematurely erode? Shouldn't cement be strong enough to withstand salt (de-icers) Note: the city uses sand as opposed to salt.
- Is it a cement/water mix issue or the curing methods used by the installer? The developer is claiming that this is a reaction commonly resulting from de-icing salts, but to me I think he's using that as an excuse to get out of it.

To add to this frustration, the developer is saying that we should get a core sample done to find out the cement/ratio mix and how that compares to the standard. The only thing is that the sample is a $2,000 job and I can't guarantee that the results will 100% help my case.

Does anyone have any recommendations as to what my options are?

Thank you in advance!
 

Last edited by Zapper; 05-27-09 at 06:28 PM. Reason: Title
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Old 05-27-09, 08:03 PM
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The de-icing chemicals are almost certainly to blame. Read any concrete literature at all and it will say not to use de-icers, especially on concrete less than a year old. Google search for your state's Ready Mix Concrete Association and read up on it. Unfortunately for you, there is probably no way that you will win this argument. The fact that the city uses sand instead of salt should tell you something.
 
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Old 05-27-09, 08:35 PM
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Old Concrete Driveway Spalling/Flaking

After only 10 moths it hard to tell if it is just poor workmanship/finishing or a real long-term durability problem.

Since you did not post your location, all you can get is wild guesses.

Whoever ordered the concrete may just not have specified a proper mix. Around here, the minimum acceptable for exposed slabs is 4000 psi with 5% air entrainment. Some producers will deliver and dump less but if the driver sees it is a slab for a driveway he will dump if a liability waiver suppled by the driver is signed in advance. Other producers will not allow the driver to unload and bring the concrete back to the plant.
 
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Old 05-28-09, 04:53 AM
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Even with proper air content and finishing techniques, salt on concrete less than a year old is a no-no and is specified as such in most literature. That said, improper mix and finishing can certainly lead to the same problems you're seeing.
The only way I see you could prove your case is to obtain a copy of the batch ticket with incriminating information on it. This information would be: an indication that air-entrainment was omitted, or a notation by the driver stating that a lot of water was added to the mix or that he saw the finishers putting water on the surface and working it in. Short of that, I see absolutely no way to win this argument.
 
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Old 05-28-09, 05:45 AM
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Another thing to check is the bag of salt/de-icer you used. Most will say "safe to use as directed" or something of the sort. They may say to wash off the surface or broom off the puddles after thawing. If you actually read the directions, they may say "do not use on concrete less than a year old" some say 2 years. If your concrete was poured in July, that means it was about 6 months (or less) old when the de-icers were applied. Even if you could prove something with the concrete mix/finishing, the additional factor of using ice-melt prior to a year of curing would probably negate any claim you may have.
 
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Old 08-28-09, 01:34 PM
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We have had the same problem with our driveway but we did not use salt on it. We live in the Chicago area, had the driveway installed in September of 2008 and saw it starting to flake in May 2009. The area that started to flake did not have any car parked on it. However, my son parked on a different part of the driveway (where salt from the road probably melted on the driveway) and there was no flaking there.

Does this sound like bad concrete mix? Thanks for any help you can provide.
 
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Old 08-28-09, 02:25 PM
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As much as almost any contractor will tell you otherwise, it is extremely uncommon to get a "bad mix" With computerized batch plants, the material is usually not to blame. It is far more likely that contractor error is the culprit. For instance, if a contractor adds too much water to the mixer truck to make the concrete more flowable, it makes the concrete weaker. If he adds water to the surface of the slab in order to "work up the cream" to get a better finish, the surface is weakened and is likely to flake off. Since de-icers were not used in your case, I'd guess that this is exactly what happened. Unfortunately, you'd never be able to prove it unless you had photo or video documentation of them finishing the concrete.
As to the "bad mix", I have seen a few over the years. One slab never set up because the batch plant added all fly ash instead of portland cement. Another had many small areas of soft spots due to problems with the mix, and several times I've received loads where it was obvious that the batch plant loaded my concrete on top of the remnants of someone else's load, creating a "flash set" situation. It happens, but is fairly uncommon.
 

Last edited by Pecos; 08-28-09 at 02:32 PM. Reason: add'l info
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