Salt-damaged concrete repair ideas.

[RJP]

I had a 24-foot length of concrete sidewalk replaced this past summer. The day the guy did the job, it was 97 degrees outside (in New Jersey). The guy who did the job was by himself and was really struggling trying to get the whole thing poured and floated, etc., before the concrete set up. The concrete truck driver even tried to help him because the guy seemed overwhelmed.

This week, after a few months of snow and ice, and some salting and shoveling of the sidewalk, I noticed the concrete is surface is crumbling and falling apart. The part that is crumbling is the center area of the sidewalk along the second half of the sidewalk that was poured. That's the part that was setting up too fast while the guy worked.

The damaged area is just the very top layer that has completely eroded (maybe the top 1/16th inch) and I can see the concrete stones instead of a smooth surface.

As far as having the guy come back, that's probably not an option. I'm not sure I could even find him. I picked him out of a newspaper ad and just had him do the work the next day because I needed it done. By the time he was done, I just paid him but knew I would never use him again. He left a big mess of left over concrete, etc

Here's my question. Is there anything that I can do to try to "seal" or refinish the surface to help prevent future erosion? Are the other techniques that could be done to perhaps have the surface scraped and refinished just to seal the concrete and make it look a little better than it does now?

My hunch is that there is nothing I can really do and, if I want it fixed, I'll just have to have it taken out and redone. But, just in case, I thought I'd check here to see if anyone has any other ideas or suggestions.

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[m Ransley]

It was the mixers - suppliers BAD mix. Judge Judy---- It will only get worse - Redo all of it

[Joseph Meehan]

In my opinion, nothing is really going to do the job. You can try one of the latex concrete products, but I would not have too much faith that it will really work. Then again, it may be worth the try.

BTW you are right about the cause. He likely overworked, or underworked the job. It also could have been a bad mix from the truck. My bet is a little of both.

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[Chris Lewis]

According to RJP :

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Sounds to me that the surface dried too quickly (should have been wetted), and the resulting surface didn't completely hydrate. Which leaves it particularly vulnerable to spalling, chipping etc.

If you're lucky, the now-exposed surface is reasonably stable and won't get (much) worse.

There really isn't a good way to repair concrete in high wear areas like this in thin layers. If you were to do it "properly", you'd probably chip out so much of the slab in prep that there's nothing left.

If it's reasonably acceptable as-is, I'd leave it a year and see if it gets worse. If it isn't, or it does, then the best bet is to replace it.

[Hawkeye]

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suggestions.

Sounds to me that the surface dried too quickly (should have been wetted), and the resulting surface didn't completely hydrate. Which leaves it particularly vulnerable to spalling, chipping etc.

If you're lucky, the now-exposed surface is reasonably stable and won't get (much) worse.

There really isn't a good way to repair concrete in high wear areas like this in thin layers. If you were to do it "properly", you'd probably chip out so much of the slab in prep that there's nothing left.

If it's reasonably acceptable as-is, I'd leave it a year and see if it gets worse. If it isn't, or it does, then the best bet is to replace it.

[RJP]

Thanks to all for your responses and suggestions.

Looks like I'll probably end up having to get the sidewalk replaced since there doesn't appear to be any kind of resurfacing process that will work.

[Chris Lewis]

According to Hawkeye :

A _good_ concrete job is pretty much immune to salt. We pave our highways with concrete, and in the winter spray salt on them, and they still last a long time (usually longer than asphalt) with all that pounding.

Concrete mixing and installation has a number of pitfalls for the unwary.

Problems with concrete tend to be either a bad (or wrong) mix, and overfast curing.

Surface spalling is usually a lack of air entrainment, however, if the surface cured too fast (as it seemed to), the surface layer will be somewhat powdery and highly vulnerable to spalling or erosion due to freeze/thaw.

When having concrete work done, it's always a good idea to ask if it has air entrained, what strength rating it is, and consider reinforcement (rebar or fiber mix).

These days, especially in freezing climates, air entrainment should be (IIRC)

6%. 4000 PSI or better strength. Fiber reinforcement is relatively cheap and painless, and good insurance.

[Joseph Meehan]

Hawkeye wrote: > I'd heard that salting concrete surfaces would

Salt is not good for concrete, but after it is fully cured, it does not have too much of a problem with it. Curing properly takes at least six months and I suggest trying to keep salt away from it for at least a year. The result of salt is very similar to poor workmanship (overworking or underworking) and in this case there was a good indication of a workmanship problem.

[calhoun]

[Jerry Levine]

I had the same thing happen to me up North. The contractor poured the concrete walk and steps late in the afternoon. After 4-6 months it looked like it was pockmarked. The contractor refused to do anything unless I paid him to remove the old concrete and redo the job. I took him to small claims court and won. My nephiew is a big builder and he told me that the concrete was on the truck too long and a chemical reaction set in to cause this problem. What did I do to correct it? After cleaning out any loose debris and sand, I went to Home Depot and got this product to apply to the concrete. Cement workers call it 'milk'. I forgot what the product name was bu t they can tell you in HD. I painted this product on and waited for it to dry. Then I spread a very thin coat of cement over it. Looked great it's 8 years since I've done it with no flaking or peeling.

[calhoun]

I know the stuff your talking about. Ask the salesperson for milky white bonding agent, it seems to always get a chuckle. Glad you had good luck with it.